More ?? on Molding Aft Deck.

WEll..got the mold done (pink foam on a balsa base) and joined up a balsa blank. The piece needed to be a trapezoid about 5" wide in front and 2-1/2" at the aft end and about 18" long.

I started with a straight 2" wide center section and joined two "wedges" to make the blank. I used the Bob Hunt edge joining technique with CA. I have never had one of these come apart on a wing skin or other.

I soaked the 3/32 material in near boiling water for about 3 hours re-applying hot water about 4 times during that time.

Everything looked good until I began wrapping the blank onto the mold. The CA joints just came apart.

Do I need to use epoxy to edge-glue these blanks so it will be water-proof?

Any suggestions?

Thanks

Don't soak them so long is my suggestion. If you use several layers of 1/32 balsa, like I do, the soaking time is very short.

Curt,
Something else you might try is edge gluing with regular modal cement.. This can be sanded without dificulty and might work better for you....

Capt,
Sounds like they just soaked too long. I ran into a similar problem when skinning the last turtledeck. Three sheets glued together with Pica instead of CA. One joint separated, not the other one. I never had a problem w/CA. (??)
Bill <><

Perhaps that is it. I left it in the water for a long time because:

a) it was 3/32 thick

and

b) at the back end, the bend radius is about 1/8 of an inch

I wanted to be sure it wouldn't split.

I might try again with couple plies of 1/16th instead, but I need to get past the glue coming apart. CA sure beats using Ambroid or epoxy for joining. (speed wise)

Capt,
Just an idea, but many times I used a small "block" at the rear to do away with the "tiny radius" problem.
Bill <><

Ron B.
F4Fguy

Curt:

Unless the curvature is very severe,you don't need that extreme a soak.For mild curves,I only do(about)15 minutes.If I'm laminating two or more 1/32 or 1/20 I rarely "soak" at all,just dip in the water,wait a few minutes,dip it again and lay it up.

If I'm dealing with severe compound curves I usually make smaller individual pieces to the approximate shape required,then piece the final part together by cutting and fitting.I use either Ambroid,thinned 20% or Pica Gluit.Attached is a fairly extreme example.It's a bit of a PITA but it's light and strong.The main thing is not accepting"good enough",go slowly cutting and fitting.You need zero-zero glue lines,the strength is in the wood,not the glue.If the parts start to dry while you're working,spray the outside with water when everything fits,assemble.Cover the buck with Saran wrap.Glue the pieces together on the buck.Lay on more Saran,and wrap it up with either ace bandage or shrink film.Like most things it's harder to explain than to do.

As the Brits say,"soldier on".

WEll, nearly successful on the second try.

I did up another 3/32 blank, relocating the joints a little. 6 lb A grain. I soaked it in bath temp water for 1/2 hour. It went right over the mold but split 1/2" at the very end where the radius was 1/8".

I'll either fix it or put in a solid block right at the end. I'm gonna try one more blank and soak it progressively--a little more time at the end.

Looks good so far.

Thanks to all.

I really hate it when you get molding on your aft deck. I have some real good fungicide that someone recommended to me that with a good stiff bristle brush and some scrubbing with take it right off the puppy in no time at all.

Jake

Yeah..I HATE IT when that happens. I once raced a boat that was so slow....