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Building Tips and technical articles. => Building techniques => Topic started by: Avaiojet on February 01, 2014, 07:05:45 PM
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Has anyone ever put together a table, based on the average weight of the different thickness/sizes of sheet balsa?
Wouldn't be a difficult thing to do.
Charles
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By happy coincidence, the weight of a 3" x 36" x 1" slab of balsa, in ounces, is equal to its density in pounds per cubic foot.
So if you have a virgin piece of 3" x 36" balsa just get its weight in ounces, then divide by its thickness to get its density.
I grade all my balsa when it comes in the door now, so if I want to know the density of a piece I just look at the end where I wrote it down with a felt pen. This still doesn't keep me from building heavy planes, but it does make me feel like I'm doing something useful.
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a quick search on here,,
three results,,
not a chart, but many methods to calculate
http://stunthanger.com/smf/index.php?topic=7070.0
http://stunthanger.com/smf/index.php?topic=13917.0
http://stunthanger.com/smf/index.php?topic=25280.0
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And, of course: http://www.nclra.org/Programs/BalsaDensity.php
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Guys
Thanks for that info and links.
I was thinking more along the lines of having a list of sheet sizes and what their weights are.
List the "light weight," "medium weight," or a "heavy weight" for a given piece.
An examplie would be my old stash.
Here's what I have:
seven sheets of 1/32 x 4 x 36, weight in oz. .4, .4, .3, .3, .4, .4, .5, .4
five sheets of 1/16 x 4 x 36, weight in oz. .5, .3, .4, .5, .5
four sheets of 1/8 x 4 x 36 weight in oz. .9, .9, .7, .6,
For those individuals that go to the hobby shop to pick out their own sheets, a table would be helpful. Just bring a scale.
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There are numerous charts and nomographs in the British literature, many in Solarbo ads. I have paper copies of same if someone wants to make a PDF. I use Tim's weigh and calculate method.
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SIG has had a balsa density chart in their catalogs since they have been printing them. If you would just spend ten seconds on a Google search, all kinds of balsa density charts come up and charts have been available from many other sources even before the invention of the internet. Makes one wonder why a man of your alleged years of modeling experience, and prowess on the computer would need to ask such a question?? n~ n~ n~ n~ n~ n~ n~ n~ n~
Type at you later,
Dan McEntee
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Guys
Thanks for that info and links.
I was thinking more along the lines of having a list of sheet sizes and what their weights are.
List the "light weight," "medium weight," or a "heavy weight" for a given piece.
An examplie would be my old stash.
Here's what I have:
seven sheets of 1/32 x 4 x 36, weight in oz. .4, .4, .3, .3, .4, .4, .5, .4
five sheets of 1/16 x 4 x 36, weight in oz. .5, .3, .4, .5, .5
four sheets of 1/8 x 4 x 36 weight in oz. .9, .9, .7, .6,
For those individuals that go to the hobby shop to pick out their own sheets, a table would be helpful. Just bring a scale.
but that information is only of minor value without converting to a density value (lbs per )
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SIG has had a balsa density chart in their catalogs since they have been printing them. If you would just spend ten seconds on a Google search, all kinds of balsa density charts come up and charts have been available from many other sources even before the invention of the internet. Makes one wonder why a man of your alleged years of modeling experience, and prowess on the computer would need to ask such a question?? n~ n~ n~ n~ n~ n~ n~ n~ n~
Type at you later,
Dan McEntee
Gee Dan,
A man of your prowess should realize that a "chart" of which I speak, isn't available. If there was such a chart, density wouldn't have to be considered. Sure would make buying wood at any shop easier.
Type back at you
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Anybody who went to high school (paid for by my tax money) has the mathematical prowess to generate such a chart for himself in a few minutes.
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Yep math is one way this is the other http://www.nclra.org/Programs/BalsaDensity.php
8 gram 1/16x3x36 is good figure form there 1/8 would be 16 grams and so on. This is 4.5 pound wood and that is what I try to build with. I can come close without a scale.
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Anybody who went to high school (paid for by my tax money) has the mathematical prowess to generate such a chart for himself in a few minutes.
Sure, I can make the chart quite easily and have one for myself, as you say, but wouldn't that be selfish?
Could have been great for others to contribute by weighing there balsa and developing a chart weight, based on size that everyone" could use.
Especially those that aren't experts.
But, I guess these Posts have taken care of that.
As usual
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http://www.go-cl.se/balsa.html
Here is a link to the Sig chart and other interesting stuff. No need to reinvent the wheel, Google is your friend.
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download either of these two links
greatest tool I have ever used and best part is it's free
http://clflyer.tripod.com/Downloads/balsa_wt_16.htm
http://clflyer.tripod.com/Downloads/balsa.htm
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Gee Dan,
A man of your prowess should realize that a "chart" of which I speak, isn't available. If there was such a chart, density wouldn't have to be considered. Sure would make buying wood at any shop easier.
Type back at you
A chart of which you speak is EXACTLY what we have been talking and posting about, and have been available in some shape or form since balsa has been used for model airplanes. There are very good articles in the old magazines back into the 1930's on how to build your own scale for weighing you balsa, and figuring it's density. If you have been involved with building model airplanes for any perceivable length of time, and have read ANY books or magazine construction articles during that time, or have ever perused a vendors list of available stock, you would HAVE to have become aware, even by accident, that balsa comes in varying weights and/or densities. Almost every model construction article ever written starts out with "Pick the lightest, best quality balsa you can....." or something similar. Even calling out for specific densities and grain structures for specific parts. Even beginner type models have this spelled out, because this is one of the first basics that you learn no matter what kind of model it is. Beginners sometimes don't pay attention to it at first, but as they progress they learn the effect that the weight of balsa has on the final outcome of their project. There is no such thing as "average weight" of a piece of balsa. The quicker a balsa tree grows, the lighter the wood is, the slower it grows, the heavier it is. If you handle enough wood over a period of time, you develop a feel for the good stuff. It is beneficial to be able to identify wood by sight and feel, if you happen to run across some good wood in a craft store or other location than an hobby shop. We are usually interested in 4 to 6 pound per cubic foot balsa, especially if it's for top blocks, bottom blocks, wing tips and wing sheeting. A little heavier and harder for high stress parts. Balsa can weigh as little as two to three pounds per cubic foot, but is very uncommon, and is usually kind of punkish and soft. It can grow as heavy as 20 pounds per cubic foot, which is what Guillow's used to make their kits out of at one time, it seems! LL~The most common stuff in the balsa rack at the hobby shop can run in the 6 pound to 10 pound range. Most balsa suppliers offer the 4 to 6 pound stuff as "contest grade" and even can supply the harder stuff if you specify. SIG offers it up to 12 pound density, I believe. Experience helps you tell the difference sometimes just by picking up a piece, and lets you know just what is going into a model even before you build it. Balsa for hobby actually makes up a very small percentage of the balsa that is harvested and we get the stuff that is kind of left over from other industries, and the buyers for the hobby industries have to watch the comings and goings of shipments to be able get us the best stuff possible. There is no "season" for growing balsa, it grows where ever it wants to in the rains forests in Ecuador and other South American countries. Attempts at growing plantation style had been tried but not successful. I have heard stories that the suppliers of balsa to the ARF model industry in China have been successful in farm raising balsa, and that is why it has the "look" it has, almost clear with very little grain, but I don't know that for sure. Even the ARF manufacturers run into shortages, though.
That is the basics of balsa.
Type at you later Chuck,
Dan McEntee
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"Pick the lightest, best quality balsa you can....."
Then, when your takeapart system is a little sticky and you give your wing a tug to dislodge it and then grab it when it goes flying across the room, it shatters. That's what I get for working on airplanes instead of watching the Superbowl like a real American.
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Sure, I can make the chart quite easily and have one for myself, as you say, but wouldn't that be selfish?
Could have been great for others to contribute by weighing there balsa and developing a chart weight, based on size that everyone" could use.
Especially those that aren't experts.
But, I guess these Posts have taken care of that.
As usual
Could be people are tired of contributing to your endless, already been answered questions due to your deleting their comments.
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Then, when your takeapart system is a little sticky and you give your wing a tug to dislodge it and then grab it when it goes flying across the room, it shatters. That's what I get for working on airplanes instead of watching the Superbowl like a real American.
Well, you didn't miss much. The Broncos forgot to show up and your team won. One of the most boring Super Bowels I have ever seen. Not really much in the way of commercials either. Try a little silicone spray on the components. I built a new starter/field box, and the little drawer I made was, like you described, "a little sticky" and would come flying out and spill when I opened it. I spayed some silicone spray on the drawer sides and bottom, and now I can't keep it closed! Have to put some sort of catch or latch on it now. My Mom showed me a trick one time when I was a kid and that was to hit sticky wood parts or drawers with a bar of soap, or bees wax. Worked better than candle wax. I don't know if she ever found out that we used to get into the bees way dispenser in her sewing kit to lubricate our yoyo strings to make them sleep better!
Type at you later,
Dan McEntee
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Then, when your takeapart system is a little sticky and you give your wing a tug to dislodge it and then grab it when it goes flying across the room, it shatters. That's what I get for working on airplanes instead of watching the Superbowl like a real American.
Howard,,
how bad is it hurt ? Lord thats all you need now,, ??? ???
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It's all fixed. It was one of my more benign disasters.
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Come on guys there are some guys who don't know about the chart. No need to hammer Charles for bringing it up. A stupid question is the one you don't ask.
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Come on guys there are some guys who don't know about the chart. No need to hammer Charles for bringing it up. A stupid question is the one you don't ask.
If anybody but myself inquired about a chart, there would have been a link in the first Post.
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If anybody but myself inquired about a chart, there would have been a link in the first Post.
Charles,, that is simply not true,,
I respond pretty much the same regardless if its you our others,, if its something that has been discussed ( to death like this)
I will point them to the search feature,, and maybe if they are new I will do the search for them
the funny part about this,, one of the threads that I came up with,, YOU POSTED ON ALREADY!! So ,, you should have known not to ask the question because you already had the answer from before!
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Charles,, that is simply not true,,
I respond pretty much the same regardless if its you our others,, if its something that has been discussed ( to death like this)
I will point them to the search feature,, and maybe if they are new I will do the search for them
the funny part about this,, one of the threads that I came up with,, YOU POSTED ON ALREADY!! So ,, you should have known not to ask the question because you already had the answer from before!
Mark,
I know you Post the same for everyone. Not the same with some others.
Yes, I did post in one of those Threads but forgot.
Relax Mark, I consider you one of my best friends.
Charles
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Mark,
I know you Post the same for everyone. Not the same with some others.
Yes, I did post in one of those Threads but forgot.
Relax Mark, I consider you one of my best friends.
Charles
charles,, your kidding right? best friends? after the nasty messages you sent me,, I doubt it
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It's all fixed. It was one of my more benign disasters.
Howard, we've all thought you could benefit from some time in a padded room -- we didn't realize you needed it for model building, though.
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Balsa wood weight chart.
This chart is exactly what I was talking about. "Exactly."
Sent to me by an individual who wants to remain anonymous. LL~ LL~ LL~
Great chart, worth the look and download.
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Hey I'm glad the topic came up. I surfed off to the Sig balsa page and read all about it with interest. And bookmarked and tagged it since I'm so forgetful. Now I better get back to cutting wood before I forget what I just learned.
Rusty
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Balsa wood weight chart.
This chart is exactly what I was talking about. "Exactly."
Sent to me by an individual who wants to remain anonymous. LL~ LL~ LL~
Great chart, worth the look and download.
And I say again, the link that Jim posted is EXACTLY what you were looking for, only more comprehensive that the chart in your link, and it's in ounces instead of grams. It doesn't matter to you either way, you don't own a scale. The SIG site shows sheets, sticks and blocks. This page on the website is what they have included in their printed catalog for 40 years or better, and has been on their website for as long as it's been in service. There are several others out there also that turned up in my Google search. You do know how to Google, don't you Chuck???? n~ n~ n~ n~ n~ n~ n~ n~
Did you walk to school, or did you take your lunch?
Dan
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And I say again, the link that Jim posted is EXACTLY what you were looking for, only more comprehensive that the chart in your link, and it's in ounces instead of grams. It doesn't matter to you either way, you don't own a scale. The SIG site shows sheets, sticks and blocks. This page on the website is what they have included in their printed catalog for 40 years or better, and has been on their website for as long as it's been in service. There are several others out there also that turned up in my Google search. You do know how to Google, don't you Chuck???? n~ n~ n~ n~ n~ n~ n~ n~
Did you walk to school, or did you take your lunch?
Dan
Dan, loosen up. It's a Hobby. Your health? LL~ LL~ LL~
You told me to buy a scale and I did. See, I take your advice. Some of it. I now have a scale. I don't have much wood, but I have a scale. n~
Hey Dan, we can be friends. Make the effort. #^
Talk back at ya! LL~ LL~ LL~
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Has anyone ever put together a table, based on the average weight of the different thickness/sizes of sheet balsa?
Wouldn't be a difficult thing to do.
Charles
Hi Charles,
My take is that a "chart" of avg. wgts. per size would not be at all useful to me. If I am going to build an important model, I am going to use all 4lb.-6lb. "Contest" balsa that I have weighed and used a calculator to determine the actual density. I have built several models where all I would use were sheets/blocks in the 4.5 - 5.5 lb. range. It has gotten harder to consistently get balsa (at least for me) under about 4.5lb. so I tend to use a lot ~5 lb.
I, too, weigh and calculate each piece of balsa when I get it to the shop. It is then marked as to its weight and I stack it from lightest on the bottom to heaviest on the top. If I need (2) pieces of 3/8th X 3 X 36 for flaps, I will order 6-8 pieces (at least) so I have a choice. You would be surprised just how much variance there will usually be in those 6-8 pieces while all are 4-6lb.
BIG Bear
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Bill,
I never heard of 4lb. balsa until I saw something about it in a Thread.
When I purchase balsa, I use the Hobby Shops, mailing scale.
Yes, one would be surprised as to the difference in sheet weight.
I'm being more careful with my building weight as per suggestions from others.
Bill,
PM me.
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I've not gotten to the point of taking a scale to the hobby shop. I knew of a now defunct shop where the owner would not allow it. I select wood by grain, look, and feel, and buy what looks good. When I get it home, I weigh each sheet, and mark the weight on it. Then, when selecting wood for a build, I use the best weight wood I have for the application.