News:


Advertise Here

  • May 23, 2022, 07:32:26 AM

Login with username, password and session length

Author Topic: laminating Balsa  (Read 2595 times)

Offline Phillip Kenney

  • Trade Count: (0)
  • Lieutenant
  • ***
  • Posts: 113
laminating Balsa
« on: September 14, 2021, 06:58:39 PM »
kit I just bought uses 2 1/4" piece to make up the 1/2" balsa fuselage. What is the best glue to use to glue the two pieces of 1/4" together?

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12440
Re: laminating Balsa
« Reply #1 on: September 14, 2021, 07:12:03 PM »
If you're willing to hold it absolutely flat for 24 hours or so, and to give it a week to dry before painting, alphatic (yellow carpenter's) glue works well.  So does epoxy.

Either way make it a thin layer -- more glue = more weight.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Dan Berry

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 908
Re: laminating Balsa
« Reply #2 on: September 14, 2021, 07:15:06 PM »
I would use slow epoxy.

Offline Dwayne Donnelly

  • 22 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 436
  • Balsa Beavers Toronto Canada
Re: laminating Balsa
« Reply #3 on: September 15, 2021, 06:32:51 AM »
Either way I leave about a half inch of glue off at the tail and nose , when I put the two pieces together I use CA where the glue is left off, that way the two pieces won't shift when they are weighed down,  ask me how I know. Lol
« Last Edit: September 15, 2021, 08:54:02 AM by Dwayne Donnelly »
My purpose in life is to serve as a warning to others.

Offline Ken Culbertson

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 4477
Re: laminating Balsa
« Reply #4 on: September 15, 2021, 07:05:47 AM »
By virtue of the grain mismatch the fuselage will be more twist/flex resistant.  If you put some very light fiberglass or CF in-between it will be even more so.  I would use a thin slow cure epoxy (Z-Poxy for example) and weight it down overnight. 

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12440
Re: laminating Balsa
« Reply #5 on: September 15, 2021, 09:14:36 AM »
Either way I leave about a half inch of glue off at the tail and nose , when I put the two pieces together I use CA where the glue is left off, that way the two pieces won't shift when they are weighed down,  ask me how I know. Lol

Or if you're scratch-building, rough-cut the pieces, glue them, then finish-sand.  That's worked well for me.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12440
Re: laminating Balsa
« Reply #6 on: September 15, 2021, 03:52:35 PM »
Nothing really stiffens if you put it on the central axis. You’d be much better off to cover the fuselage with that cf or gf. L

I was telling people that right up until the glue dried on the first fuselage that I used the technique on.  If you took two identical pieces of wood, with identical grain, and you put them together that way -- probably you'd see no change.  The key is the slight difference in grain between the wood pieces -- that seems to make all the difference in the world.

If you really want to get the full benefit, use two 1/8" sheets on the outside, with 1/4" in the center, and angle the grain by 15 degrees or so -- that should give you considerable stiffness.  Just go really light on the glue or whatever performance increase you get from a stiffer fuselage will get tossed out the window because of extra weight.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Ken Culbertson

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 4477
Re: laminating Balsa
« Reply #7 on: September 15, 2021, 04:29:27 PM »
Nothing really stiffens if you put it on the central axis. You’d be much better off to cover the fuselage with that cf or gf. L
I disagree, even a slight difference will help.

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Dave Hull

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1473
Re: laminating Balsa
« Reply #8 on: September 15, 2021, 10:17:24 PM »
If you are trying to stiffen a profile fuselage in the lateral bending mode, then putting a higher modulus material right down the centerline (on the bending neutral axis) is the least weight efficient and least effective way to do that. That is what Lauri is telling you. If you added something--anything--then sure, you gained a bit of stiffness and strength, but in the least advantageous way.

Adding the material down the center works pretty well for vertical bending resistance because the outer balsa laminations support it and tend to keep the laminate material from buckling--and some of the higher modulus material is out near the beam outer fiber, but who has vertical stiffness issues with a profile?

This type of construction adds to torsional stiffness but is harder to quantify and explain. In other words, it takes engineering language and equations for a composite beam, which is a pain to calculate by hand. (I would be concerned about shear separation at failing loads if this were more important than just a model airplane.) But again, heuristically, using the higher modulus material as the outer fiber of the structure is the only efficient way to do this.

If these concepts are not appreciated, then there really is no purpose in discussing fiber orientation or other design details needed to understand composite structures....

Dave

Offline MikeyPratt

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 677
Re: laminating Balsa
« Reply #9 on: September 16, 2021, 09:27:24 AM »
kit I just bought uses 2 1/4" piece to make up the 1/2" balsa fuselage. What is the best glue to use to glue the two pieces of 1/4" together?

Hi Phillip,
I’ve done a lot of this and tried different ways of doing this, what does work perfectly is slow epoxy (I like the Sig brand slow epoxy, but I’m sure others will work as well).  Start by placing wax paper over a flat building board, then apply the epoxy to the inside face of the fuselage, then spread out the epoxy with an old credit card, this allows to you put a thin even coat to the part.  Place on top of the wax paper and pin in place with small T-Pins by inverting the pins through the edge of the fuselage half at 45 degree angle.  Place the other half on the fuselage on top and weight the assembly down with old books and or weights and allow to cure for at least 18 to 24 hours.  If you have epoxy oozing out of the joint (more than likely you will), wipe off the excess with paper towel and alcohol.

Later,
Mike Pratt
« Last Edit: September 16, 2021, 09:53:47 AM by MikeyPratt »

Offline Mark wood

  • 22 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 858
  • I'm here purely for the fun of it.
Re: laminating Balsa
« Reply #10 on: September 19, 2021, 01:58:59 PM »
I'm a big fan of west systems epoxy for that kind of operation myself. Dave's correct, adding CF in between the balsa plies won't do much for the actual stiffness. A better way would be to put 1/2" caps on top and bottom. Even better would be to uses some super light fiberglass, .75 OZ/yd, on the sides. Glass has a similar stiffness to wood and would tend to not delaminate from buckling under load. Although adding carbon fiber definitely hits the coolness bragging rights factor up a notch. That alone makes it worth doing.
Life is good AMA 1488
Why do we fly? We are practicing, you might say, what it means to be alive...  -Richard Bach
“Physics is like sex: sure, it may give some practical results, but that’s not why we do it.” – Richard P. Feynman

Offline Ken Culbertson

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 4477
Re: laminating Balsa
« Reply #11 on: September 19, 2021, 04:02:09 PM »
If you have two 1/4" sides to laminate, you have a golden opportunity to cut a trench and lay a CF tube in there.  That will stiffen things.

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Avaiojet

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 7966
  • Just here for the fun of it also.
Re: laminating Balsa
« Reply #12 on: September 19, 2021, 04:35:57 PM »
If you have two 1/4" sides to laminate, you have a golden opportunity to cut a trench and lay a CF tube in there.  That will stiffen things.

Ken

Build a full bodied fuselage.
Trump Derangement Syndrome. TDS. 
Avaiojet Derangement Syndrome. ADS.
Amazing how ignorance can get in the way of the learning process.
If you're Trolled, you know you're doing something right.  Alpha Mike Foxtrot. "No one has ever made a difference by being like everyone else."  Marcus Cordeiro, The "Mark of Excellence," you will not be forgotten. "No amount of evidence will ever persuade an idiot."- Mark Twain. I look at the Forum as a place to contribute and make friends, some view it as a Realm where they could be King.   Proverb 11.9  "With his mouth the Godless destroys his neighbor..."  "Perhaps the greatest challenge in modeling is to build a competitive control line stunter that looks like a real airplane." David McCellan, 1980.

Offline pmackenzie

  • Pat MacKenzie
  • 22 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 734
Re: laminating Balsa
« Reply #13 on: September 19, 2021, 09:23:14 PM »
Build a full bodied fuselage.

There are many valid reasons why he might be building a profile, so not sure how this suggestion  helps ???
You might just as well have said "Buy a Yatsenko". Good advice perhaps, but completely off-point.
MAAC 8177

Offline Avaiojet

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 7966
  • Just here for the fun of it also.
Re: laminating Balsa
« Reply #14 on: September 20, 2021, 07:00:46 AM »
There are many valid reasons why he might be building a profile, so not sure how this suggestion  helps ???
You might just as well have said "Buy a Yatsenko". Good advice perhaps, but completely off-point.

It's not off point. Everyone is giving advice about "stiffness."

Save some weight also.
Trump Derangement Syndrome. TDS. 
Avaiojet Derangement Syndrome. ADS.
Amazing how ignorance can get in the way of the learning process.
If you're Trolled, you know you're doing something right.  Alpha Mike Foxtrot. "No one has ever made a difference by being like everyone else."  Marcus Cordeiro, The "Mark of Excellence," you will not be forgotten. "No amount of evidence will ever persuade an idiot."- Mark Twain. I look at the Forum as a place to contribute and make friends, some view it as a Realm where they could be King.   Proverb 11.9  "With his mouth the Godless destroys his neighbor..."  "Perhaps the greatest challenge in modeling is to build a competitive control line stunter that looks like a real airplane." David McCellan, 1980.

Offline Dan Berry

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 908
Re: laminating Balsa
« Reply #15 on: September 20, 2021, 07:50:02 AM »
It's not off point. Everyone is giving advice about "stiffness."

Save some weight also.

Many are giving unsolicited advice.
Adding stiffness was not part of the original question.
I would bet two beers that I know who made the kit in question. I'll bet one beer that I know which kit.
Epoxy is the answer to the original question.

Offline Dan McEntee

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 5551
Re: laminating Balsa
« Reply #16 on: September 20, 2021, 08:17:35 AM »
It's not off point. Everyone is giving advice about "stiffness."

Save some weight also.

     Again, proof positive that your reading comprehension skills absolutely suck, or you are just fond of your own "voice" or both!

    Type at you later,
   Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Avaiojet

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 7966
  • Just here for the fun of it also.
Re: laminating Balsa
« Reply #17 on: September 20, 2021, 10:06:43 AM »
Many are giving unsolicited advice.
Adding stiffness was not part of the original question.
I would bet two beers that I know who made the kit in question. I'll bet one beer that I know which kit.
Epoxy is the answer to the original question.

Yes, Epoxy, and a chosen material, is the remedy, unfortunately this will add a bit of weight.
Trump Derangement Syndrome. TDS. 
Avaiojet Derangement Syndrome. ADS.
Amazing how ignorance can get in the way of the learning process.
If you're Trolled, you know you're doing something right.  Alpha Mike Foxtrot. "No one has ever made a difference by being like everyone else."  Marcus Cordeiro, The "Mark of Excellence," you will not be forgotten. "No amount of evidence will ever persuade an idiot."- Mark Twain. I look at the Forum as a place to contribute and make friends, some view it as a Realm where they could be King.   Proverb 11.9  "With his mouth the Godless destroys his neighbor..."  "Perhaps the greatest challenge in modeling is to build a competitive control line stunter that looks like a real airplane." David McCellan, 1980.

Offline Brent Williams

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1058
  • Making America Fly Stunt Again!
    • Fancher Handles - Presented by Brent Williams
Re: laminating Balsa
« Reply #18 on: September 20, 2021, 12:35:38 PM »
In an X pattern.

Motorman 8)


What size carbon tow are you using for your X reinforcement?  I have some 48K tow that I might try on a profile.
Laser-cut, "Ted Fancher Precision-Pro" Hard Point Handle Kits are available again.  PM for info.
https://stunthanger.com/smf/brent-williams'-fancher-handles-and-cl-parts/ted-fancher's-precision-pro-handle-kit-by-brent-williams-information/

Offline Ken Culbertson

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 4477
Re: laminating Balsa
« Reply #19 on: September 20, 2021, 12:55:10 PM »
I an X pattern.

Motorman 8)
Is that on the outside or in-between the two 1/4" halves? 

Ken

PS:  Just our of curiosity, which is worse in a profile, twist or flex?  I understand the forces that cause flex and it's impact on the flight but I am not sure what causes twist.
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline MikeyPratt

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 677
Re: laminating Balsa
« Reply #20 on: September 21, 2021, 06:00:54 PM »
Hi Phillip,
I don’t think Phillip asked about carbon fiber, he was asking about gluing to pieces of 1/4” balsa together to form a fuselage.  This works perfectly with slow dry epoxy or Slightly thinned Tite Bond glue (hell, I would bet you could use Gorilla glue to get a good bond).   With the Tite Bond glue it has to set up under the weights a lot longer. 

Note:  Place the T Pins through the edges so as not to in the way when placing the second sheet in place.  Good Luck Phillip on building your model.

Mike Pratt

Offline john e. holliday

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 22162
Re: laminating Balsa
« Reply #21 on: September 22, 2021, 01:16:23 PM »
Well from experience putting my Primary Force together,  Gorilla Glue is the way to go.  Make sure you have a roll of Parchment paper(found in the Baking section of the store) on both sides of the laminate on a very flat surface.  The Gorilla Glue will find every worm hole in the balsa and once it cures the excess can be sanded off and is the lightest glue I have found.  Draw back is the glue does not have a very long shelf life.  Also I think I would break the laminate before it bends. D>K
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530  Have fun as I have and I am still breaking a record.

Offline Dave Moritz

  • 22 supporter
  • Trade Count: (0)
  • Commander
  • *
  • Posts: 308
Re: laminating Balsa
« Reply #22 on: October 03, 2021, 11:36:39 AM »
Gentlemen:

Back to some serious thread drift!  A SIG Skyray kit build for my Winter project, might want to stiffen the fuselage so suggestions needed. Recently, Ken has suggested youth fiberglass arrow shafts embedded top and bottom of half-inch fuse. Not sure how to interpret Lauri's ideas, but am intrigued.

What say ye all?

Dave Mo...
...with the naked Earth beneath us, and the Universe above. (C Stevens)

Offline MikeyPratt

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 677
Re: laminating Balsa
« Reply #23 on: October 03, 2021, 02:01:29 PM »
Gentlemen:

Back to some serious thread drift!  A SIG Skyray kit build for my Winter project, might want to stiffen the fuselage so suggestions needed. Recently, Ken has suggested youth fiberglass arrow shafts embedded top and bottom of half-inch fuse. Not sure how to interpret Lauri's ideas, but am intrigued.

What say ye all?

Dave Mo...

Dave,
The Skyray is good the way it is, it’s not that long of a fuse, unless you want to drive post holes.  Most of the crash’s I’ve seen the Skyray’s fuse were pretty much intact, the wing takes the beating for the most part.  A strip of CF down each side of the fuse can help but not really needed.  I’ve seem all kinds of mods to the Skyray 35 some mods work pretty good, and the others not so much, they just added more weight.  When I first designed the Skyray 35, it was to use up the short balsa & plywood that were in the saw room in the plant.

Things that do work well such as;  3/32 balsa ribs, hard balsa spars, extending the span of the elevator 1/2” at each of the stab tips and increasing width & span of the elevator by 1/2”.  If glow powered add a balsa nose cheek from 3/8” or 1/2” balsa from the nose back to the wing spars.  Also, use the landing gear from a Twister or bend your own out of aluminum.

Later,
Mike Pratt

Offline Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 12583
Re: laminating Balsa
« Reply #24 on: October 03, 2021, 02:49:37 PM »
Dave,
The Skyray is good the way it is, it’s not that long of a fuse, unless you want to drive post holes.  Most of the crash’s I’ve seen the Skyray’s fuse were pretty much intact, the wing takes the beating for the most part.  A strip of CF down each side of the fuse can help but not really needed.  I’ve seem all kinds of mods to the Skyray 35 some mods work pretty good, and the others not so much, they just added more weight.  When I first designed the Skyray 35, it was to use up the short balsa & plywood that were in the saw room in the plant.

     I have to agree that the plywood wing is suboptimal. On the first significant crash with mine, just about every single plywood part was shattered into multiple pieces, I had a nice monokote bag full of scraps. The fuselage was just cracked lengthwise and the tail was perfectly intact. The balsa version I made to replace it was was *6 ounces* lighter, which only slightly improved the performance with the 20FP, but survived many crashes - at least 50 of varying severity - only finally requiring a serious repair after the monokote had turned to glass and shattered in a mild pancake crash.

    I agree the fuselage is perfectly fine as is, same with the tail surfaces. I recently passed my original model to the next generation. I plan on making a slightly modified replacement, the only consequential change being about 1.5" shorter tail moment, with a correspondingly larger stabilizer to get the same TVC. I have always been running into the pitch rate limit long before I got a stall, so I want to increase the max pitch rate slightly.

      Brett

   

Offline Dan McEntee

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 5551
Re: laminating Balsa
« Reply #25 on: October 03, 2021, 04:16:07 PM »
  The Skyray .35's that I have scratch built I used 3/16" balsa for the ribs and kept the same spacing. I had a bunch of strips left over from experiments in cutting my own balsa from planks and this stuff was pretty light but stiff. The first one was built that way about the time the kit came out, and it has been through the mill for all sorts of duty like balloon bust and such, and I have lost track on the number of recover jobs on it. It's still hanging in the garage ready for use if needed! Any future versions will most likely be built the same way but will try the slightly larger stab, haven't tried that yet.
  Type at you later,
  Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Dave Moritz

  • 22 supporter
  • Trade Count: (0)
  • Commander
  • *
  • Posts: 308
Re: laminating Balsa
« Reply #26 on: October 05, 2021, 10:16:18 AM »
How about some poetry?

This drift brings out the big guns
I'll build it as is...
So let it be written, so let it be done.

Thanks to all!

Dave Mo
...with the naked Earth beneath us, and the Universe above. (C Stevens)

Offline Dave Moritz

  • 22 supporter
  • Trade Count: (0)
  • Commander
  • *
  • Posts: 308
Re: laminating Balsa
« Reply #27 on: October 05, 2021, 10:18:38 AM »
PS:

With the balsa ribs!

Dave Mo
...with the naked Earth beneath us, and the Universe above. (C Stevens)

Offline Scott Richlen

  • AMA Member
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1936
Re: laminating Balsa
« Reply #28 on: October 05, 2021, 12:25:03 PM »
Quote
  have to agree that the plywood wing is suboptimal. On the first significant crash with mine, just about every single plywood part was shattered into multiple pieces, I had a nice monokote bag full of scraps. The fuselage was just cracked lengthwise and the tail was perfectly intact. The balsa version I made to replace it was was *6 ounces* lighter, which only slightly improved the performance with the 20FP, but survived many crashes - at least 50 of varying severity - only finally requiring a serious repair after the monokote had turned to glass and shattered in a mild pancake crash.

    I agree the fuselage is perfectly fine as is, same with the tail surfaces. I recently passed my original model to the next generation. I plan on making a slightly modified replacement, the only consequential change being about 1.5" shorter tail moment, with a correspondingly larger stabilizer to get the same TVC. I have always been running into the pitch rate limit long before I got a stall, so I want to increase the max pitch rate slightly.

      Brett 

Brett:

What do you use for the control system?  3" or 4" belcrank?  Horn size?

The reason I ask is that I finally finished a bad-luck Peacemaker I started many, many years ago.  It has a stock control system and it flies awful.  I would like to build one that flies well (if that is possible).  It's a sentimental thing....

Thanks!

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12440
Re: laminating Balsa
« Reply #29 on: October 05, 2021, 02:29:39 PM »
I think the Skyray is good just the way it is, and won't be recommending any changes when my wife builds one.

In fact, I built some 40-sized stunt trainers, the "design" effort involved keeping the Skyray's basic aerodynamics (aspect ratio, TVC, etc.) with enough of a scale-up so that the plane would fly well on Schnurle-ported 35 or a Tower 40.  The first one I failed to scale up the fin area correctly and it had yaw problems -- making the fin match the Skyray fin fixed that.  The second one I didn't screw up the fin, and it flew right off the board.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 12583
Re: laminating Balsa
« Reply #30 on: October 05, 2021, 07:22:37 PM »



Brett:

What do you use for the control system?  3" or 4" belcrank?  Horn size?

   It's a 3" SIG bellcrank straight out of the kit, and a nylon CG "Large" RC control horn, in the second hole (maybe 3/4" from the hinge line). Stock 3/32 music wire pushrod, unbushed and crimped leadouts.

    The original intent was to build this kit (which I acquired to give me a guide to rebuild someone else's airplane - after I crashed it...) for my work buddies to fly at a picnic, and the expected lifespan was <<1 hour. So I did absolutely nothing other than cut out a new fuselage (which I had used in the other rebuild) and stick it together exactly how it came. Picnic never happened.

    Dixon 40FP, which I never even *ran* before I gave it to someone to use on their Twister, later Fox 35 (disaster, although I beat David in a contest with it), sat for 2-3 years,  L&J Fox 35 with bypass mod at least ran until it started shaking itself apart, next weekend OS 20FP/Circus Hobbies 9.5-4.5, miraculously better. This takes us up to *1996*....

    You get the idea, the notion that it would be flying with more-or-less stock moving parts after closing in on 30 years was the furthest thing from my mind.

     I can't see any compelling reason to use a 4" bellcrank, the control loads are nearly non-existent. It won't hurt anything, of course.

    Brett

Offline Dan McEntee

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 5551
Re: laminating Balsa
« Reply #31 on: October 05, 2021, 08:01:48 PM »
  Some where in my archives of printed stuff is a sketch where a 4" bell crank was drawn with typical pushrod locations and such and how much throw that had, and superimposed over that was a SIG 3" bell crank and what hole location was needed to mimic those throws. I think the flap push rod hole is 7/16" from the center hole, or something like that. Some one may know for sure. SIG has a tall nylon control horn with as much space as you would need to fine tune the flap and elevator throws as you could want. Between that and adjustable line spacing you can dial in anything you would need to be comfortable.
  Type at you later,
  Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline doug coursey

  • Trade Count: (0)
  • Ensign
  • **
  • Posts: 31
Re: laminating Balsa
« Reply #32 on: November 27, 2021, 07:38:26 AM »
Well from experience putting my Primary Force together,  Gorilla Glue is the way to go.  Make sure you have a roll of Parchment paper(found in the Baking section of the store) on both sides of the laminate on a very flat surface.  The Gorilla Glue will find every worm hole in the balsa and once it cures the excess can be sanded off and is the lightest glue I have found.  Draw back is the glue does not have a very long shelf life.  Also I think I would break the laminate before it bends. D>K

is this the stuff that expands when it dries...like foam
AMA 21449

Offline Les Akre

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 205
Re: laminating Balsa
« Reply #33 on: November 28, 2021, 08:18:56 PM »
Hi Phillip

As already mentioned, if I was to glue two pieces together, I would use one of the many laminating epoxies available. If you already have some, then you're good to go. Just park some heavy weight(s) on the glued pieces, over the flattest surface you can find before they set up. I've done this a few times for solid wings as well.

If however, you don't have any laminating resin, it's probably less expensive to just buy a piece of 1/2" balsa and use that.

Les

Offline Ken Culbertson

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 4477
Re: laminating Balsa
« Reply #34 on: November 28, 2021, 08:33:00 PM »
Yes Gorilla glue expands. If you don't clamp the parts you'll have a balsa/foam sandwich.
The carpenters Gorilla glue doesn't expand like the regular Gorilla.  It acts just like Titebond only stronger.

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12440
Re: laminating Balsa
« Reply #35 on: December 01, 2021, 01:34:15 PM »
The carpenters Gorilla glue doesn't expand like the regular Gorilla.  It acts just like Titebond only stronger.

Ken

You can't just say "Gorilla Glue" any more and know it's the green urethane foaming stuff.  They have all sorts of glues these days -- green foaming, white foaming (which turns green in the sun after a while), epoxy, aliphatic (Titebond), CA, and I think one or two more.  Plus construction tape.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Fredvon4

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2165
  • Central Texas
Re: laminating Balsa
« Reply #36 on: December 01, 2021, 04:27:11 PM »
Usually when I laminate between Balsa sheets I use epoxy and a top flite wood pecker tool

not sure who sells them any more Tower is a worthless site not for any building stuff

Ebay seller is out of his ever loving mind for one 
https://www.ebay.com/p/2255975934
"A good scare teaches more than good advice"

Fred von Gortler IV

Offline Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 12583
Re: laminating Balsa
« Reply #37 on: December 01, 2021, 06:45:48 PM »
Usually when I laminate between Balsa sheets I use epoxy and a top flite wood pecker tool

not sure who sells them any more Tower is a worthless site not for any building stuff

Ebay seller is out of his ever loving mind for one 
https://www.ebay.com/p/2255975934

  That seems rather excessive/highly optimistic

    But, if you are using epoxy, poking holes is unnecessary, you have plenty of bond-line strength just gluing the flat pieces together.

   As per the other thread, while the right kind of epoxy is ideal, almost anything that says glue on it will work as long as you are careful about warps. Plenty of these sort of jobs were formerly done with Amrbroid (which is the worst possible choice) and even though it might never dry all the way in the middle of the sheet, it was plenty good enough.

      Brett

Offline Will Hinton

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2739
    • www.authorwillhinton.com
Re: laminating Balsa
« Reply #38 on: December 01, 2021, 07:29:20 PM »
A brief comment on the original gorilla glue, someone said it doesn't have a good shelf life, and that can be true, bur doesn't have to be.  I use a ton of it in the guitar building process and lose very little to shelf life.  The key is to squeze as much air out of the container as possible before capping.  It goes and goes and.....
John 5:24   www.fcmodelers.com

Offline Mark wood

  • 22 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 858
  • I'm here purely for the fun of it.
Re: laminating Balsa
« Reply #39 on: December 01, 2021, 07:53:05 PM »


   As per the other thread, while the right kind of epoxy is ideal, almost anything that says glue on it will work as long as you are careful about warps. Plenty of these sort of jobs were formerly done with Amrbroid (which is the worst possible choice) and even though it might never dry all the way in the middle of the sheet, it was plenty good enough.

      Brett

Yeah, but Ambroid had "that smell"....
Life is good AMA 1488
Why do we fly? We are practicing, you might say, what it means to be alive...  -Richard Bach
“Physics is like sex: sure, it may give some practical results, but that’s not why we do it.” – Richard P. Feynman

Offline Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 12583
Re: laminating Balsa
« Reply #40 on: December 01, 2021, 11:29:15 PM »
Yeah, but Ambroid had "that smell"....

    The best smell in the world! And also, great for chewing off your fingers for the next few days. CA is definitely second-rate in that regard.

      Brett

Offline Ken Culbertson

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 4477
Re: laminating Balsa
« Reply #41 on: December 02, 2021, 06:55:46 AM »
Yeah, but Ambroid had "that smell"....
Ambroid, it brought out the best in my Mother:  "OPEN THE G.. D... Window".  How many kids do you know that got a window fan for Christmas?

So now we have CA and it brings out the best in my wife: "OPEN THE G.. D... Window".

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Scott Richlen

  • AMA Member
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1936
Re: laminating Balsa
« Reply #42 on: December 02, 2021, 07:10:34 AM »
Quote
  Ambroid, it brought out the best in my Mother:  "OPEN THE G.. D... Window".  How many kids do you know that got a window fan for Christmas?

So now we have CA and it brings out the best in my wife: "OPEN THE G.. D... Window".

Ken 

Ken: Good one!!!  When I was a kid I got in real trouble after I dropped a jar of clear dope on the floor (oh yeah, it broke!!)

Offline Mark wood

  • 22 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 858
  • I'm here purely for the fun of it.
Re: laminating Balsa
« Reply #43 on: December 02, 2021, 06:46:59 PM »
    The best smell in the world! And also, great for chewing off your fingers for the next few days. CA is definitely second-rate in that regard.

      Brett

Yeah, CA just doesn't chew off right.
Life is good AMA 1488
Why do we fly? We are practicing, you might say, what it means to be alive...  -Richard Bach
“Physics is like sex: sure, it may give some practical results, but that’s not why we do it.” – Richard P. Feynman

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12440
Re: laminating Balsa
« Reply #44 on: December 02, 2021, 08:01:55 PM »
A brief comment on the original gorilla glue, someone said it doesn't have a good shelf life, and that can be true, bur doesn't have to be.  I use a ton of it in the guitar building process and lose very little to shelf life.  The key is to squeze as much air out of the container as possible before capping.  It goes and goes and.....

I'm going to try that!  Storing it top down works too.  The glue hardens in the cap but you can clean that easily; the stuff in the bottle lasts much longer.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.


Advertise Here
Tags:
 


Advertise Here