Balsa Wing Sheeting joining methods for model airplanes...
An article on ssembling multiple pieces of sheeting, by Great Planes
Here are some of the answers that were given on the Scale Aerobatics mailing list:
I have used CA for years now, and this is the way I do it... The sheets *MUST* be edge trued. Do this right before you glue them together. If they sit even an hour, do them again. The seams have to be absolutely invisible. Take a *brand new* bottle of pink Zap (it MUST be new and like water to work right) and put a "Z-End" on it. Place the sheets together and work inch by inch...glue an inch then take a paper towel and rub it in. It takes very little glue...verrrrry little. If it goes through the backside you're using too much. It should just go through but not enough for it to leak out the other side. You will be surprised how little it takes when you rub it in with a paper towel. Set your sheets up so that you're gluing the side that will face down on the foam. Be sure to use some wax paper underneath so that it doesn't stick to the table just in case some gets through. Once you get onto it there won't be any sanding at all...just some minor smoothing to even the small imperfections in the thickness of the different sheets. Be sure to have paper towels already pulled off and ready and change spots on the towel often or the dried zap on the towel will gouge...we wouldn't want to do that now would we? hehe Wicking action is the key here. It should just glue the edge but not glue it to the wax paper. One more thing...be sure to scuff the zap on the bottom that will be stuck to the foam for good adhesion. Hope this helps. Tim Durbin
When I edge
glue the sheets for skinning I tape full length on the outside surface. Then I
"crack open" the joints and use Titebond for the edge gluing.
I find if the Titebond finds it's way to the outside of the joint (under the tape) it is very easy to sand. Usually the glue just simply stays inside the joint and there isnt much trace of it at all after the tape is peeled off.
After the glue dries you can either go ahead and do your skinning and sand the joints later, or you can sand the joints first on the outside surface, then do the skinning. Sanding on the outside surface first allows you to lay the sheets flat on the work table and you get a very even sanding job from sheet to sheet.
What we are doing lately though is to simply make sure the sheets are edge trued properly then do the taping, again full length on the outside surface.
Then we apply our ProBond,
being sure we get the adhesive into the joint between the sheets as you squeegee
it on. If you like you can even "crack" the joints a bit to be
sure the ProBond gets n there. Then continue putting the ProBond on the
skin and put it all back in the shucks. BINGO, Finished
I don't see why you couldn't do this the same way with epoxy. Bob Hudson
I use Pica Glue-it to join sheeting it sands as if it was balsa. Dave
I don't know if you can use polyurethane glue when
vacuum bagging, but if that works, then you could do what I do for joining the
sheeting. [rcfaq.com note: I haven't vacuum bagged, but from what I
hear, vacuum bagging eliminates the benefits of polyurethane glue. Namely, that
adhesive will swell up to fill voids, but it can't do that in a vacuum.] All
you have to do when using polyurethane glue is tape the edges of sheeting
tightly together, flat on the bench. Make up the entire skin that way and
then coat it with a thin sheen of polyurethane glue, then apply to the cores,
press as usual. The glue squeezes in between the taped sheeting edges as
it activates and expands, thus bonding them securely. Much less work this
way, since you only sand the outer surface when all is dry. Ed
All of the information on this
web site is copyright 2000 by rcfaq.com. All rights reserved.
Revised: April 18, 2006 .