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General control line discussion => Open Forum => Topic started by: Bob Hunt on December 26, 2018, 09:52:31 AM
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As most of you know I produce, among other things, sheeted foam wings through my Robin's View Productions company. I strive to get the very best materials possible, and it is always a struggle to obtain large quantities of contest grade 4 to 6 pound/cubic foot density wood. I just spoke with my supplier and told them that I was not getting the requisite amount of such wood with my recent orders to fill my wing orders. I was told that contest grade balsa will very soon become a thing of the past. There are industries that are using huge amounts of balsa to make their products (mostly to make those huge props used on "wind farms.”) Those industries have been buying up all the wood that is available - including the light stuff... - and leaving only the dregs for those who service the modeling industry.
The situation is not as dire as you might think, if you are willing to change your thinking about how we use balsa. Back in the 1970s I produced wings under the company name Control Specialties (and before that Control Line Specialties...). We had a similar problem getting consistently light wood back then. In those days the industry that was using all the available balsa was ship building. Specifically freighters that required holds that were refrigerated. Balsa was the ideal (at that time) insulating material, and we had a bear of a time getting good light wood for many years. When they found other, better, insulating materials, the balsa supply eased up a bit and we could once again get some decent density wood. During that period I started using .045 (3/64-inch) thick balsa for sheeting, and virtually all of the wings that I produced throughout the 1970s were covered with that thickness wood. Because the wood was thinner, but of a heavier density, the actual finished weights of the wing panels were no different than they had been when using the lower density 1/16 wood. But, the denser wood did not soak up as much finish, and, because of that, the models built around those wings actually came out lighter overall. I even covered several foam core wings with very dense 1/32-inch balsa, and those models came out very light when finished. An added bonus is that the denser wood is also stronger than very soft but thicker wood.
I order wood in lots of several hundred sheets at a time, and then grade the wood when it arrives. I use wood that is 8 to 9.5 grams per sheet for the inboard panels, and wood that is 10 to 10.5 grams per sheet for the outboard panels. This is done to reduce the amount of tip weight that is required, and to make use of the wood more efficiently. The wood that grades out heavier than 10.5 grams per sheet is sold locally to modelers for rib stock for built up wings, or to the local RC guys. Even so, I have stockpiled a lot of slightly heavier density wood; more than I can use or sell.
In talking with a good friend of mine abut this problem and explaining how we used to use denser but thinner wood, he revealed to me that he had a micro sander that could be used to make .045 sheets out of my stock of unusable .062 (1/16-inch) wood. Long story short, I delivered to him about 500 sheets of that wood, and he has so far sanded about 100 sheets to .045. And, it is beautiful! A sheet of 1/16 x 3 x 36 that weighed around 11 grams came out to weigh about 8.5 grams at .045. Woo Hoo!
We have all been used to getting wood from hobby shops and/or suppliers that was cut to the popular thicknesses that have been the paradigm for years. Remember, balsa does not grow in 1/16, 3/32, 1/8, 1/4, 3/8 -inch thicknesses. We can get it cut and sanded to whatever thickness we desire.
I have been using denser 1/16 wood for top and bottom shells for a long time. The denser wood takes a bit longer soaking to be moldable easily, but when fully soaked, it bends around the bucks jut as easily as the softer 3/32 that is most often used to make shells for our models. An added benefit is that the denser, stiffer wood will not cave in between the formers and give that “starved horse” look. I have also been using stiff 1/16-inch balsa for fuselage sides instead of 1/8 or 3/32-inch balsa, and have had great results.
All I am saying is that we will most likely have to adjust our paradigms to the reality of what will be available to us in balsa densities in the very near future. If we do, we can continue to produce light and strong models for years to come.
Later - Bob Hunt
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Thanks Bob for the info. I have used heavier but thinner balsa ever since I played with F2C competition. Yes the heavier wood did not soak up the epoxy or other finishing materials as much as the light wood. Even today I have some light balsa that is shelved as it is no good for ribs and is why I use thicker wood. I guess I'm a clutz when it comes to handling light wood. D>K
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This is depressing news.
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I get balsa from a lot of sources. I generally look for straight grain and consistency. I have, for years, used heavier but thinner pieces as Bob suggests. Seems to work out fairly well.
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When I was flying slope gliders I would vacuum bag wings with epoxy soaked brown wrapping paper. Extremely light and remarkably strong. If needed, an under layer of light fiberglass at the root, out about a quarter of the span.
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STUPID WIND FARMS! 😠
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STUPID WIND FARMS! 😠
AGREE!!!!!
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When I was flying slope gliders I would vacuum bag wings with epoxy soaked brown wrapping paper. Extremely light and remarkably strong. If needed, an under layer of light fiberglass at the root, out about a quarter of the span.
In the 70's I knew a pattern flyer,( lived in my building actually and helped me a lot), who used news paper. y1
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Don't worry, be happy...
...with blue (or pink) foam:
https://stunthanger.com/smf/building-techniques/the-bluefoam-model-or-how-to-build-a-stunt-plane-without-a-bit-of-balsa/
Thanks to God (and DOW or Corning Glass and CIBA-Huntsman) I could succesfully forget balsa from early '80s for a life... :)
Istvan
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We used to use 1/40 Obeche veneer over foam. Light and extremely strong. I have also been a fan of thinner stiffer wood except for blocks. Just out of curiosity, what happens to the balsa in one of these generator blades when it breaks or one of those ships gets scrapped. Is the wood salvaged?
Ken
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We used to use 1/40 Obeche veneer over foam. Light and extremely strong. I have also been a fan of thinner stiffer wood except for blocks. Just out of curiosity, what happens to the balsa in one of these generator blades when it breaks or one of those ships gets scrapped. Is the wood salvaged?
Ken
I'd guess that the ships would probably have a life of many decades, and I read that wind generators aren't even maintained, because there's not much they can do to repair them due to the sheer size and height...so they're allowed to burn to the ground. Those in central California may not like that thought, but maybe they have fire system installed or have a fire-watch stand by that one that's trying to make smoke. I've also read that their electron output per $/lifetime isn't a good payoff, but it makes certain factions happy. HB~> Steve
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The sheer Volume or numbers of very very big things in this world is astounding, and kind of frightening from a source of raw materiel point of view
Balsa and Mahogany ( there are many others) are a cash crop and a major source of GDP for many countries...so they slash rain forest to gain land to grow cash crops
I sometimes wonder (tongue in cheek) if the Global Warming "Sea water is rising" folks account for all the DISPLACEMENT of the GIANT ships we build
Or for that matter the displacement from any of 20 or so active volcanoes...but I digress
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I have nothing to add on the original topic, Bob has it right.
But, the inverse of his theory is something you need to watch out for, and had burned people many times over the years. Bob's points is that you can use heavier wood with thinner dimensions to get the same strength. Conversely, if you use lighter balsa, you generally want to *increase* the dimensions of the wood. What I see, time after time, is someone wanting to build "the world's lightest Belchfire" and replacing all the 6-7 lb wood and replacing it with 4 lb wood of the same dimensions. It's lighter, alright - so it's easier to carry to the garbage can when it falls apart. This is particularly bad when you do it with ancient 40's-50's designs like the Ringmaster, Firecat, etc, which only stay together if you have pretty stout wood due to the very poor engineering of the structure.
I haven't seen any real data on the phenomenon, but to save weight with lighter wood, the specific modulus or specific tensile strength would have to go up as the density goes down. That might be true, but I haven't seen any evidence of it. Otherwise, its just designed wrong to start with, and could be made lighter by reducing the size of the heavier wood.
What kills people on weight is overbuilding, using lots of plywood, and using lots of filler and paint. Good worksmanship alone can greatly reduce the filler, and not getting a glazed look in your eye when picking up the spray gun, will be much more effective.
Brett
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Very interesting info Bob, but like you say there's no reason to overreact. Basically, thicker or thinner or whatever, it all boils down to wood selection as we build, just like it always has. :)
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Reading Aeromodeler way back when, Europeans were completely competitive with all hardwood for their models. It can be done!
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Well I just received my latest box of unobtainium from Stunt Hangar Hobby 3.5 to 5 LB wood. Great stuff
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Reading Aeromodeler way back when, Europeans were completely competitive with all hardwood for their models. It can be done!
When? Dick Korda was winning Wakefield because his models were 1/3 the weight of the hardwood/bamboo paper models - about 100 years ago. Pioneer British modeler Colonel Bowden decried models built of "balsa models held together with blobs of model cement", instead of wrapping each hardwood joint with thread and hide glue.
If you think it can be done, I would like to see a demonstration - say, an all-hardwood Impact/40VF at 64 ounces with a competitive finish.
Brett
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If you think it can be done, I would like to see a demonstration - say, an all-hardwood Impact/40VF at 64 ounces with a competitive finish.
Brett
Brett,
Check with Avaiojet, he can probably post photos of the one he did. ;D
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Brett,
Check with Avaiojet, he can probably post photos of the one he did. ;D
Yes, expect a post very soon about how he told Colonel Bowden about it in the first place.
Or I could just buy one of them, since he is selling them (or trying to) instead of flying them as he claimed...
Brett
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...and not getting a glazed look in your eye when picking up the spray gun...
So that’s why it’s so heavy. I’ll change the mask filters before painting the next one.
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Of course technically speaking, balsa is a hardwood.
Spruce is a softwood.
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Bob thanks for sharing that information. PhillySkip
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Maybe we should start thinking that maybe, just maybe, that those extra 100 coats of clear to get that 20 point finish is something we really don't need so much but my guess is that we will just get bigger engines, thicker lines and design a harness to keep your shoulder attached.
Ken
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I'm still finding 5-8lb/ft3 balsa at Ace Hardware stores that carry the Midwest line of balsa and spruce. I'm mostly looking for 1/16" sheets but you have to go through the entire stack to find them. Holding each piece up to the ceiling lights to see how much light shines through tells you accurately enough how dense it is. You have to brave the stares from the patrons making detours down the adjacent aisles, though.
Ara
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Maybe we should start thinking that maybe, just maybe, that those extra 100 coats of clear to get that 20 point finish is something we really don't need so much but my guess is that we will just get bigger engines, thicker lines and design a harness to keep your shoulder attached.
Finishes have generally been getting lighter, rather than heavier, as people start to use more advanced paint systems. Still, if someone treats auto clear like dope, better get harder tires on your wheels because it's going to leave a flat spot. Done correctly, a good automotive clear adds about 3/4 oz - 1 oz. But one individual who shall remain nameless (since it WASN'T Larry..) managed to add *17 ounces*.
Brett
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I remember back in the 70's the Navy had a big ship building program and was using a great deal of balsa to line hulls for strength and floatation, especially during the oil embargo when foam was very high priced. Somewhere we got a little New Guinea wood. It was light and nice but I seem to remember it was yellowish in color compared to Ecquador wood. I suppose a good source for that might be found in Australia etc., but shipping and import duties might be ugly. I just ordered a little. I try to keep on hand enough for the next future project-whatever that ends up being.
Dave
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Demand feeds supply . .
As many folks know I have been supplying 3-5lb balsa to the stunt community for nearly a decade and I chose to close my doors to direct and in person contest sales due to lack of demand - NOT LACK OF SUPPLY.
Light wood is simply more costly than medium to heavy balsa and being blunt, a lot of stunt folks simply don’t want to pay what it actually costs (for whatever reason).
Light wood comes from young trees and they are both less interesting to loggers (as there is less wood on a young tree) and more expensive to harvest as cutting early reduces the profit for the logger. Young trees that fall are often sadly used as kindling for the Kilns!! As loggers often regard treating them for sale as too costly. I worked with one team to rescue this light wood to stop it being used for Kindling a couple of years back and it worked out well for everyone.
Bottom line is if you want light wood, be prepared to pay for it and patronize the suppliers like; Tom and SIG who continue to supply it and you won’t loose the supply.
Right now though I would agree with Bob with a caveat; No Demand = No Supply.
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Balsa was also considered to insulate the second-stage hydrogen tank of the Saturn 5. Then ended up using spray-on polyurethane because the quality control of balsa was so difficult - more or less the same issues we have, no two pieces are really alike, particularly when you are trying to insulate a rocket that is 33 feet in diameter! The had process control over the insulation.
The same polyurethane insulation was used on the Shuttle external tank, and then when it got saturated from rainwater and then frozen by the hydrogen, was notorious for falling off early in the boost. That's what went through the leading edge of the Columbia, leading to the disaster on re-entry.
Interestingly, on the third stage of the Saturn V, they put the insulation on the inside instead of the outside, so it could only fall off and get sucked into the engine. But that never happened in practice, as far as anyone can tell.
Brett
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So I am going to offer a differing point.
In late October I was in Marinette Wisconsin and called up the balsa USA guys to see about getting visit.
The took me on an awesome tour. Photos were not allowed.
If you are ever up there, call them for a visit, it was awesome. I hand picked some 1/2 inch planks for some future profiles that I want to build
I saw the wood milling operations, resawing and kit production area.
I also saw their balsa storage room and asked about the"balsa shortage" I was let to believe that wood was scarce.
The huge room (75' x 50; , 20 foot roof. was huge and full and overflowing with blanks of wood. the blanks are roughly 3.5" x 3.5" x 48" I think. To make larger sheets they did a glue up in dedicated wood press and a resaw. it was impressive. Multi blades saws like used for slicing bread. They have probably 30 resaw stations.
Per Balsa USA There is NO SHORTAGE of balsa
They can buy all the Wood they have cash for. They are frequently asked by their supplier to take more than they want.
They buy as much as they can, but no shortage per their view.
Contest balsa is scarce, but in their view there is no shortage of wood. A lot of it was 8lb + grade.
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I did not intend to start a panic with my initial post. The sky is not falling yet, but when it does, watch out for heavy balsa. And, don't say I didn't alert everyone to information that I received from a reliable, extremely informed source...
Bob
Perhaps the sky is not falling but this topic has shed light on the fact that (IMHO) it should be the overall weight and weight distribution that we are after, not what we use to get there. Weight is made up of three components. The air-frame, the power plant and the finish. Some of us can afford to choose the power plant to match the other two but a lot of us can't so we have to build for what we have. I think it is time to start thinking in terms of lighter finishes to make up for what will be heavier frames. However, Bob said something that really struck home. The wings he produced with thinner harder wood were lighter and stronger than the ones with thicker lighter wood. I remember some of those wings and he is right. I also remember skinning sailplane wings ( you think we pull g's, try a zoom launch) with 1/40th veneer of some very straight grained stuff that was not balsa. Why are we not still doing that?
We have adapted to all sorts of shortages over the years. If it happens, this one will be no different.
Ken
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I think the issue in general is any wood now isn't as lice as old growth stuff. Now balsa mills ship in the beam sized wood, before they shipped a whole log and it could be cut and graded. no so much when it come pre milled in a 4x4 post.
I think that can use more of the tree that way, and shipping costs are less.
In the ware house at balsa usa I am sure there was some contest wood there, but they did not separate it.
But they had an impressive operation, lots of kits in stock and lots of wood finished in the bins. Many machines all busy and more old machines to be refitted.
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There are many good articles in the old magazines on balsa and the process of producing usable wood. The last time we went through this, there was rumors that there was some success in plantation growing of balsa. It is difficult to do because of the huge amounts of water needed ( like in a rain forest) and because of the pollination process for it to grow One reason I heard the last time this went around was that the clear cutting of the rain forests was eliminating the other plants needed to cross pollinate the balsa tree, which is really kind of a weed and as some one mentioned, is hectically a hard wood. One of the plants needed is also a plant whose flower is a key ingredient in the local people's version of moonshine! And their business was taking off, so to speak, at that time. When the flow of ARF R/C models really began to flow from China, we would examine the kits at the hobby shop and I noticed the wood looked really 'clear" with hardly any grain, like some one else mentioned here. I had heard through the indoor crowd that the stuff being grown on plantations was really desirable for the microfilm jobs. You don't need much wood for those, and it was opposite of what Brett mentioned, as it was pretty consistent and predictable. If you ever get your hands on any of the Air Sail brand of free flight kits out of New Zealand the wood in those looks like what I mentioned. The last time this was discussed on the forum here, someone posted a link to several companies web sites that showed what they offered in plantation grown balsa wood. I agree with the statement that the wood you need is dependent on what you want to use it for and the stress it will have to take. Nothing has changed in this respect at all over the years. We've had it pretty good for the last 10 or 20 years as far as getting the good stuff, and I have a pretty good stock so I won't worry about it. When the tanker created shortage was going on, I worked a lot of hours at the hobby shop at that time and was the resident balsa guru. We did have some difficulty getting ANY kind of wood for a while, and I was always accused of weeding out the good stuff for myself before putting the rest out in the balsa rack.But I can honestly say I did NOT do that, not as far as anyone else knows!
Type at you later and HAPPY NEW YEAR!
Dan McEntee
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BALSA WOOD INDUSTRY - PAPUA NEW GUINEA
https://www.youtube.com/watch?v=AA-3cvYFXao
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Most of you guys have the solution to this in your pile of un-built kits. I happen to have a Strega kit that is essentially a box of balsa perfect for re-design into something that would fly much better. In fact, it's such a lumber yard that I might, by careful re-design, get two planes out of it!
Balsa shortage? What balsa shortage?
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So I am going to offer a differing point.
In late October I was in Marinette Wisconsin and called up the balsa USA guys to see about getting visit.
The took me on an awesome tour. Photos were not allowed.
If you are ever up there, call them for a visit, it was awesome. I hand picked some 1/2 inch planks for some future profiles that I want to build
I saw the wood milling operations, resawing and kit production area.
I also saw their balsa storage room and asked about the"balsa shortage" I was let to believe that wood was scarce.
The huge room (75' x 50; , 20 foot roof. was huge and full and overflowing with blanks of wood. the blanks are roughly 3.5" x 3.5" x 48" I think. To make larger sheets they did a glue up in dedicated wood press and a resaw. it was impressive. Multi blades saws like used for slicing bread. They have probably 30 resaw stations.
Per Balsa USA There is NO SHORTAGE of balsa
They can buy all the Wood they have cash for. They are frequently asked by their supplier to take more than they want.
They buy as much as they can, but no shortage per their view.
Contest balsa is scarce, but in their view there is no shortage of wood. A lot of it was 8lb + grade.
An interesting side effect of the ARF industry and the general dismal state of RC craftsmanship (that I learned when I got involved with Elliot's effort)- the kit and ARF industry *doesn't want light wood*, it's "too weak". It wouldn't surprise me to find out that they get a batch, go through and sort it by density, and then *toss* the very light wood, or burn it. Elliot can clarify, but I got the impression that he got the wood, sorted it (with a little help from his friends..), culled what we wanted, then sold the rest of it to the ARFers, who were glad to have it pre-sorted to get rid of the weak stuff!
Elliot proved to me that there is no real shortage of contest wood, just a shortage of ways to get to it. He had a pretty big *box truck* full of it, probably enough to supply everyone here for life, and very little of it above 6 lbs. Distribution is another story...
Brett
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Brett’s account is largely correct.
None of this hunt for light wood is free, it takes time and costs money but light wood can be found. The important question though is: “do builders genuinely want light wood and are they willing to pay the price of it”?
My answer after more than a decade of sourcing and helping builders is that the vast majority of control liners don’t want to pay for it (even if they SAY they want it).
Sport flyers don’t see low density wood as a necessity and some don’t even care what their planes weigh. Thus comes the demand argument again.
Windy Urtnowski (who many of us know of) was a multi award winning Concours d'Elegance and top 5 Nat’s competitor who sourced his light wood by buying SIG “contest wood” by mail order. As his local hobby shops rarely stocked this stuff, mail order was his only way. He would buy 3 times more than he needed to build a plane and then he DISCARDED 66% OF WHAT HE BOUGHT as reject. Making the wood he used effectively 300% MORE EXPENSIVE.
- Even to me, that is very serious money invested in Balsa!
How do I know all this? - I stood with Windy in his basement workshop one day and watched him sift through his latest balsa order into useable and not useable with his Radio flyer friend standing by to take away the rest.
High quality craftsmen like Bob Hunt, rightly still find this high cost and sourcing a big challenge as they have to include a lot of light balsa in the parts they make. BUT . . . if control line builders demand good balsa and are willing to pay for it, suppliers will re-emerge.
The real challenge is not supply, but light wood that is CHEAP ENOUGH for the majority of stunt and free flight flyers, and no, I don’t have a solution for that one - good balsa costs more, plain and simple.
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Another source of light, inexpensive balsa is crashed C/L planes built by serious stunt flyers. Purloined from the fields trash barrel, I use the wood for crash repairs and rubber scale builds.
Ara
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Interestingly, on the third stage of the Saturn V, they put the insulation on the inside instead of the outside, so it could only fall off and get sucked into the engine. But that never happened in practice, as far as anyone can tell.
Brett
Interesting, how does a piece of debris get "sucked into" a rocket engine?
Chuck
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Interestingly, on the third stage of the Saturn V, they put the insulation on the inside instead of the outside, so it could only fall off and get sucked into the engine. But that never happened in practice, as far as anyone can tell.
Brett
Interesting, how does a piece of debris get "sucked into" a rocket engine?
Chuck
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Balsa was also considered to insulate the second-stage hydrogen tank of the Saturn 5. Then ended up using spray-on polyurethane because the quality control of balsa was so difficult - more or less the same issues we have, no two pieces are really alike, particularly when you are trying to insulate a rocket that is 33 feet in diameter! The had process control over the insulation.
The same polyurethane insulation was used on the Shuttle external tank, and then when it got saturated from rainwater and then frozen by the hydrogen, was notorious for falling off early in the boost. That's what went through the leading edge of the Columbia, leading to the disaster on re-entry.
Interestingly, on the third stage of the Saturn V, they put the insulation on the inside instead of the outside, so it could only fall off and get sucked into the engine. But that never happened in practice, as far as anyone can tell.
Brett
Brett, how exactly does a piece of debris get sucked into a rocket motor? Also, there was technically no third stage on a Saturn V. They went from S2 to the S4B. Oneof the few little useless facts we learned in rocket scientist school.
Chuck
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Brett, how exactly does a piece of debris get sucked into a rocket motor? Also, there was technically no third stage on a Saturn V. They went from S2 to the S4B. Oneof the few little useless facts we learned in rocket scientist school.
When the insulation falls off the inside of the tank. The S-IVb had the insulation inside the tank.
The Saturn V most certainly did have a 3rd stage, it was the S-IVb. The third is, well, 3rd, regardless of how you name it.
Brett
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When the insulation falls off the inside of the tank. The S-IVb had the insulation inside the tank.
The Saturn V most certainly did have a 3rd stage, it was the S-IVb. The third is, well, 3rd, regardless of how you name it.
Brett
So your argument is that a buoyant piece of material will sink to the bottom of the tank under thrust, make it past the inducer (remember, for the TLI burn the SIVB pump had an NPSHA equal to the vapor pressure of cryogenic LOX at startup) and into the turbopump? I can't remember if there was a pogo suppressor on the SIVB's motor. Number 2, you NEVER, NEVER, EVER under any circumstance put flammable organics into a LOX tank or in contact with the LOX.
Regarding the Saturn 3rd stage - Bret, that's an inside rocket joke. Yes, technically the SIVB was the 3rd stage, but back in my rocket days we would never refer to the 3rd stage in the stack, simply the SIVB. The Saturn V 3rd stage was a unicorn. I came along after the S5's were retired but I studied under the people who designed it. We're so off topic now we can do this PM if you want, but if you're so interested you can research "Pi Ratios" for rockets - and also how you need to change the nozzle geometry as the back pressure changes - and then the history of the S5 "third stage".
Fun discussion, I can go on about rockets and Top Fuel Motors for days!
OK, we're way off topic and we should continue this via PM. Or over some cold ones, my treat.
Chuck
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Brett’s account is largely correct.
None of this hunt for light wood is free, it takes time and costs money but light wood can be found. The important question though is: “do builders genuinely want light wood and are they willing to pay the price of it”?
My answer after more than a decade of sourcing and helping builders is that the vast majority of control liners don’t want to pay for it (even if they SAY they want it).
Sport flyers don’t see low density wood as a necessity and some don’t even care what their planes weigh. Thus comes the demand argument again.
Windy Urtnowski (who many of us know of) was a multi award winning Concours d'Elegance and top 5 Nat’s competitor who sourced his light wood by buying SIG “contest wood” by mail order. As his local hobby shops rarely stocked this stuff, mail order was his only way. He would buy 3 times more than he needed to build a plane and then he DISCARDED 66% OF WHAT HE BOUGHT as reject. Making the wood he used effectively 300% MORE EXPENSIVE.
- Even to me, that is very serious money invested in Balsa!
How do I know all this? - I stood with Windy in his basement workshop one day and watched him sift through his latest balsa order into useable and not useable with his Radio flyer friend standing by to take away the rest.
High quality craftsmen like Bob Hunt, rightly still find this high cost and sourcing a big challenge as they have to include a lot of light balsa in the parts they make. BUT . . . if control line builders demand good balsa and are willing to pay for it, suppliers will re-emerge.
The real challenge is not supply, but light wood that is CHEAP ENOUGH for the majority of stunt and free flight flyers, and no, I don’t have a solution for that one - good balsa costs more, plain and simple.
Bingo. If you want really DELICIOUS wood, you need to pay three times more, because YOU will be sorting out the best and getting rid of the rest...it has always been that way.
Ever see what a piece of indoor grade wood cost from Indoor Model Supply back in the day? Like ten times normal cost? Because...they did that work. They did not call up a supplier and get indoor quality wood...they did the sorting.
As someone who bought balsa by the container to manufacture ARFs in China...trust me, there is no shortage of wood. There is a lot more balsa production around than there used to be, thanks to windmill manufacturing.
The balsa arf market for radio control is GONE. Done, over. Most of the factories have closed. Foam took over. The kit market is long gone. I know, there is Brodak, BUSA and such, but it's all a tiny shadow of what it was.
Point is...you can get all the balsa you want. And you can get all the super light balsa you want. But you will have to pay for buying much more than you need and sorting out what you want...if every gram counts.
BUSA does not sell to ARF manufacturers...because there ARE no ARF manufacturers here in the USA. Only Vietnam(where most balsa ARF manufacturing has moved due to increased labor costs in China) and China. It is simply not possible to make a competitively priced ARF here in the USA.
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Thank goodness!
Dave
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Does anyone else wonder why balsa is so absolutely necessary for them windmills? Because structurally they could as well be made with foam core materials.
Maybe it's got something to do with long term resistance of structure?
But anyway, raping all that tree from rainforests does not exactly match with their image as clean energy:) L
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Many moons ago I was a boat designer/engineer working in that industry. It was common to use end grain balsa in fiberglass hulls for stiffness. It lays up with the resin perfectly and doesn't require an additional process to apply as would foam. The foam is an oil-based product which can cost more at times at least. I'd believe that many engineers working in the windmill business came from the boat making industry and could spec balsa because of it's known usability and simple familiarity with using it. Just an educated guess...
Dave
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Does anyone else wonder why balsa is so absolutely necessary for them windmills? Because structurally they could as well be made with foam core materials.
Maybe it's got something to do with long term resistance of structure?
But anyway, raping all that tree from rainforests does not exactly match with their image as clean energy:) L
I agree, the same issue they had with it for cryogenic tank insulation would appear to apply - difficult QA. You would think an engineered material would be a lot better, at least they would have a chance of knowing the properties. With balsa or any other natural product, it's just a crap-shoot, or requires extensive sorting or categorizing, and there is no guarantee that you are even going to be able to get the same thing next time. That's a problem in the construction industry, too, they farm it to be able to have some control over it.
Brett
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..but of course, balsa is one of the best core materials when it comes to extreme compression loads, most foams don't even come close. But I don't see extreme loads in those blades. In that use, unless you count possible flutter and temperature variations as such. L
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..but of course, balsa is one of the best core materials when it comes to extreme compression loads, most foams don't even come close. But I don't see extreme loads in those blades. In that use, unless you count possible flutter and temperature variations as such. L
Right, but I would think that might be trumped by its extreme variability (more-or-less the premise of Bobby's post) - you never know what you are going to get. That's why they invented aluminum and aramid honeycomb, that's almost as good and the volumetric density can be much better than balsa.
Another point (also in line with the original premise) - by the time it gets to you, the waste/"shrinkage" on a piece of 1/16 balsa is astronomical, maybe 500-1000% if you select out contest balsa from a random batch. That would appear to apply to the wind turbine people, too, since you would have to be very careful and toss a lot of wood to maintain any semblance of repeatability.
Brett
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Maybe they make windmills from balsa because
FOAM SUCKS.
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In the boat building scenario and I would think the wind blade construction they are somewhat overbuilt making selection not too critical. They likely buy it like we did-cut end grain (about 2" thick) and bound with a glass mesh cloth in something like 4 X 8 sheets. Those who manufacture this core would have to be those picking the wood. I don't recall having 'grades' offered. It was laid into the resin chop mix in the mold then sprayed over and rolled down. It was certified for this use by the industry association and I know with a design safety factor. Must be also true for the wind blades. Some of these blades in my area are as big as rail cars. A bunch of balsa has to go into each.
Dave
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Actually, I did what I should've done earlier and found lots of interesting reading just by googling "Balsa in windmill blades" 🤔
It appears that it's used especially in highly stressed root but often also in rest of the blade.
honeycombs are difficult to use in resin infusion molding. L
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Demand feeds supply . .
As many folks know I have been supplying 3-5lb balsa to the stunt community for nearly a decade and I chose to close my doors to direct and in person contest sales due to lack of demand - NOT LACK OF SUPPLY.
Light wood is simply more costly than medium to heavy balsa and being blunt, a lot of stunt folks simply donÂ’t want to pay what it actually costs (for whatever reason).
Light wood comes from young trees and they are both less interesting to loggers (as there is less wood on a young tree) and more expensive to harvest as cutting early reduces the profit for the logger. Young trees that fall are often sadly used as kindling for the Kilns!! As loggers often regard treating them for sale as too costly. I worked with one team to rescue this light wood to stop it being used for Kindling a couple of years back and it worked out well for everyone.
Bottom line is if you want light wood, be prepared to pay for it and patronize the suppliers like; Tom and SIG who continue to supply it and you wonÂ’t loose the supply.
Right now though I would agree with Bob with a caveat; No Demand = No Supply.
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Our balsa needs are minuscule in the world context. Aside from control line stunt no one is weighing the sheets. WeÂ’re also an endangered species. Probably dying off. Too few of us to mate and perpetuate the genome. Even folks building doll houses out number us by many factors. Jose Modesta molds competition planes from fiberglass. By the by. IÂÂÂ’ve seen those creations drub many traditional models. I saw a Windy Miss Ashley for sale on eBay. 650 or so for the components. Not bad. Balsa feels good as we cut, sand and mould. Vacuum bagging, laying up epoxy soaked fibers, resembles assembly line manufacturing. Mindless drudge work...
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Too few of us to mate and perpetuate the genome.
Well, I guess there could be a big enough crowd at Brodaks for that to happen....
Ewwwwwwww! :o
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Our balsa needs are minuscule in the world context. Aside from control line stunt no one is weighing the sheets.
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Free flight modelers weigh balsa sheets very carefully. With my background in FF and CL, I would even weigh balsa sheets if I built an RC model out of balsa. Of course, the number of free flighters added to number of CL flyers is still a miniscule number of people using 4 to 6 lb wood.
Joe Ed Pederson
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Indoor fliers are fanatic about wood. Razor thinning sheets. Look at their spidery creations. Barely any balsa mass left. A good size tree or two of the right stuff would probably supply most of us for quite a while. Serious competition free flight went to carbon fiber. DidnÂÂ’t they? Or Kevlar. Last time I looked. Yeah. Old farts at Brodak have a ball. Me included. Going forward weÂ’’re poor candidates for procreation. Lololo
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Okay, so we need about 3 guys to volunteer. Your mission: fly down to Ecuador (or where-ever, I'm an engineer, not a geographer), cut down a couple of prime light balsa trees , tie them together, and raft them back to the good ole USA. I got a chainsaw out in the garage and a table saw in the shop. So if you guys will do that, I think I can handle the rest.
Okay, so who wants to volunteer? Show of hands, please?
S?P
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Naw. Not me. I got the chainsaw part. ;D
With your previous international experience and balsa expertise I volunteer Bob to be our official raft leader!
We need two more volunteers to follow Bob under his illustrious leadership. Anyone? Anyone?
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Okay, so we need about 3 guys to volunteer. Your mission: fly down to Ecuador (or where-ever, I'm an engineer, not a geographer), cut down a couple of prime light balsa trees , tie them together, and raft them back to the good ole USA. I got a chainsaw out in the garage and a table saw in the shop. So if you guys will do that, I think I can handle the rest.
Okay, so who wants to volunteer? Show of hands, please?
S?P
Speaking of rafts,( and in a way your were) deos everyone remember the voyage of the Kontiki? I may not have the spellings correct, but a gentleman named Thor Hyderdal (I'm sure I butchered his name) wrote a book by that name on his theory that the islands in the South Pacific were inhabited by people who's ancestors sailed there in balsa rafts from South America, and recreated the trip in the Kontiki. Well, he almost made it and I think proved his point. The raft eventually made it's was here to St. Louis and ended up in the St. Louis Museum of Transport. When they took possession of it, conservation efforts were the first thing that they thought of, as it was beginning to deteriorate quite a bit. Some one from the parks department, which over sees the museum, was familiar with Bob Underwood, who many of you know as an outstanding scale builder and who led the Greater St. Louis Modeling Association for many years. What better person to ask about preserving balsa than a model airplane builder! I don't remember exactly what transpired as this was many years ago, but if I ever get back to the museum, I will be sure to ask if they still have the remains of the raft.
And along the lines of rafts, I have built many models using would I acquired form a local source that were life preservers from the old SS Admiral excursion boat that used to be moored and operated from the St. Louis river front. I bought 640 balsa planks life preservers that measured 2" by 12" by 36" for 200 bucks!. And most of it was contest grade and weight, some as light as 3 pound per cubic foot. These were made in the early 1930 and I think were on the original ship that the hull came from , which was a rail road ferry called the Albatross. I sold some off as the years went by and still have about 100 I think. I have to count them. It was great wood for wing tip and fuselage blocks!. I also have some small blocks that an since passed away club members reclaimed from a rail car that used it as insulation. I think it was common years ago to use balsa block as insulation on refrigerated rail cars and some trucks.
Type at you later,
Dan McEntee
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Great Idea! I volunteer Scott...
History's Greatest Monster - Scott Richlen or Thor Heyerdahl? Discuss...
Brett
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Don't know for sure but I was told at some point in my flying career that, as a weight savings device, the floors of airliners were made from a sandwich of end grain balsa between sheets of aluminum. I expect Howard can tell us whether that someone at some point was pulling our leg.
Ted
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I heard something along the same line, Ted, about airliner balsa core floor panels. Except in the version I heard, the earliest attempts used too thin of an aluminum facesheet on the top. This was in a fashion era of women's spike heels. They found that the contact pressure was higher than the panels could take....
I have a bunch of sandwich coupons I collected over the years from different work projects. The nomex core and others are interesting, but the aluminum/balsa/aluminum sample could be used to build bridges.....
Dave
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History's Greatest Monster - Scott Richlen or Thor Heyerdahl? Discuss...
Brett:
Is this your shyness showing through? Does this mean you are in? Report to Captain Hunt immediately!!
Now, we need just one more volunteer. Hopefully one with a parrot.......Arrrrgggh!
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[quoteWell, he almost made it ][/quote]
Not if the raft ended up in St. Louis.
How did he get across the isthmus? The canal wasn't there during Incan times....
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[quoteWell, he almost made it ]
Not if the raft ended up in St. Louis.
How did he get across the isthmus? The canal wasn't there during Incan times....
Kon-Tiki was made of contest balsa. He tucked it under his arm and just walked it across the Isthmus. Shows the importance of good wood selection.
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I live on hardtack, salt beef, rum, and the occasional seagull. It toughens you up.
I'm pretty sure on the Kon-tiki he used the heavier logs for the outboard side.
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Speaking of rafts,( and in a way your were) deos everyone remember the voyage of the Kontiki? I may not have the spellings correct, but a gentleman named Thor Hyderdal (I'm sure I butchered his name) wrote a book by that name on his theory that the islands in the South Pacific were inhabited by people who's ancestors sailed there in balsa rafts from South America, and recreated the trip in the Kontiki. Well, he almost made it and I think proved his point. The raft eventually made it's was here to St. Louis and ended up in the St. Louis Museum of Transport. When they took possession of it, conservation efforts were the first thing that they thought of, as it was beginning to deteriorate quite a bit. Some one from the parks department, which over sees the museum, was familiar with Bob Underwood, who many of you know as an outstanding scale builder and who led the Greater St. Louis Modeling Association for many years. What better person to ask about preserving balsa than a model airplane builder! I don't remember exactly what transpired as this was many years ago, but if I ever get back to the museum, I will be sure to ask if they still have the remains of the raft.
And along the lines of rafts, I have built many models using would I acquired form a local source that were life preservers from the old SS Admiral excursion boat that used to be moored and operated from the St. Louis river front. I bought 640 balsa planks life preservers that measured 2" by 12" by 36" for 200 bucks!. And most of it was contest grade and weight, some as light as 3 pound per cubic foot. These were made in the early 1930 and I think were on the original ship that the hull came from , which was a rail road ferry called the Albatross. I sold some off as the years went by and still have about 100 I think. I have to count them. It was great wood for wing tip and fuselage blocks!. I also have some small blocks that an since passed away club members reclaimed from a rail car that used it as insulation. I think it was common years ago to use balsa block as insulation on refrigerated rail cars and some trucks.
Type at you later,
Dan McEntee
I think balsa life rafts were the primary use of balsa during WWII.
Like you, I also acquired a large stock of balsa planks salvaged from a ship long ago, I was told mine was used as insulation on a C3 tanker. Mine was not contest grade. I just used some to make the rear turtledeck for this 1946 King Midget single seat car I restored.
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[quoteWell, he almost made it ]
Not if the raft ended up in St. Louis.
How did he get across the isthmus? The canal wasn't there during Incan times....
Well, there is a coast of South America that is on the Pacific Ocean side! I think I read that book or parts of it when I was in grade school a whole bunch of years ago. Might have to find a copy of it and read it again. Around that time also was the voyage of the Ra, and ship made of papyrus reeds that was supposed to recreate the possible migration of people from North Africa to South American, I think it was. Memory is really foggy on that one. The last thing I would even think of doing is take on the Atlantic in anything less than an aircraft carrier! These guys that did this sure must have been passionate about their theories.
Type at you later,
Dan McEntee
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Dan,
When I was very young (4 to 6), my family used to take me on picnics aboard the original paddle wheel powered Admiral, sailing out of St. Louis. Still have fond memories of those trips over 70 years ago!
While working at Boeing Seattle I was transferred to the new Sram II missile program in Kent WA. One day I noticed a sheet of wood standing in the hall outside a closed program, and stopped to look. The label said it was balsa, but it was end cut, so of no use for building models. I've no idea what the intended use might have been, but have heard that Boeing was using it for flooring in some airplanes. Later on I found some end cut balsa in the Boeing salvage building.
Bill
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this is from balsa USA web page. This is inside their ware house. ther has to be some 6lb wood there somewhere
(https://scontent-ort2-2.xx.fbcdn.net/v/t1.0-9/50399575_1980426765409690_1896986213106057216_n.jpg?_nc_cat=103&_nc_ht=scontent-ort2-2.xx&oh=420c5d943035830f65c9610425ff6516&oe=5CD0D237)
(https://scontent-ort2-2.xx.fbcdn.net/v/t1.0-9/50317404_1980426788743021_7640916646885851136_n.jpg?_nc_cat=104&_nc_ht=scontent-ort2-2.xx&oh=55b2806afd0bee8c9e5ea010820aa3b4&oe=5CC956BD)
(https://scontent-ort2-2.xx.fbcdn.net/v/t1.0-9/50563397_1980426795409687_7606828895911804928_n.jpg?_nc_cat=109&_nc_ht=scontent-ort2-2.xx&oh=e91cf81748fc8c7ccc7b68fe98052fb2&oe=5CC6E58C)
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I stopped by there last summer. They hand picked some C-grain lightweight 1/16th for me. Think they charged $1 a sheet extra for hand-picking. Not bad, I was happy to get it.
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Saw this today. Kind of a shame....not because of the balsa, but because it's not a US plant, in spite of our fearless "leader's" citing the "fact" that windmills cause cancer.
https://cleantechnica.com/2019/04/19/absolute-beast-of-a-wooden-wind-turbine-blade-rolls-off-the-assembly-line/?fbclid=IwAR2g34uqDxdm9yPHoWqo5Rb1RWAA7mhQEEuRlnhY_LBTB3kmjLGr61w_yxA
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Saw this today. Kind of a shame....not because of the balsa, but because it's not a US plant, in spite of our fearless "leader's" citing the "fact" that windmills cause cancer.
https://cleantechnica.com/2019/04/19/absolute-beast-of-a-wooden-wind-turbine-blade-rolls-off-the-assembly-line/?fbclid=IwAR2g34uqDxdm9yPHoWqo5Rb1RWAA7mhQEEuRlnhY_LBTB3kmjLGr61w_yxA
We should be thankful that there is a high demand for balsa. Without it there would be no one growing it and our pathetically small demand would never get filled. We use their "scrap" so all we need is a few suppliers willing to take that scrap and turn it into the stuff we cherish. As for our fearless leader: I read the "fact checkers" comments. It cracked me up when I read "Trump Lied", windmills do not cause cancer, but they do cause stress and it is the stress that causes the cancer... Does anyone remember the old "If A=B and B=C then A=C? They do still teach that in school don't they? ???
Ken
der
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We should be thankful that there is a high demand for balsa. Without it there would be no one growing it and our pathetically small demand would never get filled. We use their "scrap" so all we need is a few suppliers willing to take that scrap and turn it into the stuff we cherish. As for our fearless leader: I read the "fact checkers" comments. It cracked me up when I read "Trump Lied", windmills do not cause cancer, but they do cause stress and it is the stress that causes the cancer... Does anyone remember the old "If A=B and B=C then A=C? They do still teach that in school don't they? ???
Ken
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Thank goodness they teach the scientific method in schools these days. There's absolutely zero evidence that windmills cause cancer or even stress. You'd be in greater risk of cancer from the petrol/gas you pump into your car at the bowser. That old windmill bovine droppings story has been proven to be false over and over. The problem is that a whole lot of older males are too far into denial to recognize BS.
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Thank goodness they teach the scientific method in schools these days. There's absolutely zero evidence that windmills cause cancer or even stress. You'd be in greater risk of cancer from the petrol/gas you pump into your car at the bowser. That old windmill bovine droppings story has been proven to be false over and over. The problem is that a whole lot of older males are too far into denial to recognize BS.
Sorry but I got my thoughts from an article written back when this whole "cancer" thing started where a study was done and the cause for the increase in cancer was found to be stress from all sources INCLUDING the windmills. Anyone who thinks that a constant whining noise doesn't cause stress has never had tinnitus. Conclusive evidence - hell no but zero evidence -please. I am going to pass on the older male comment. This forum has enough negative stuff as it is and I am guilty of sneaking in borderline politics so let's just leave it alone.
ken
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Seeing Ted's post reminded me of my introduction to the Vickers Viscount, courtesy of united airlines. The flooring of the pax compartment was, indeed, quarter inch plywood (hopefully not balsa) sandwiched between two thin aluminum sheets, largely with large open cutouts.
Flexible, I guess, and strong, I guess....
dg
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Don't know for sure but I was told at some point in my flying career that, as a weight savings device, the floors of airliners were made from a sandwich of end grain balsa between sheets of aluminum. I expect Howard can tell us whether that someone at some point was pulling our leg.
Tedious
I saw it at Boeing Surplus. I never saw much useful balsa there, but I got some 11-lb 4x4s.