View Single Post
Old 04-04-2019, 11:53 AM
  #4  
Silverback
Watch This!
 
Join Date: Mar 2011
Location: DC Metro
Posts: 9
Default

Originally Posted by solentlife View Post
Its as well to go back to old days methods .....

Kits 20 - 30yrs ago were common with veneered foam wings ... in fact I had a small 'business' called Wings and Things cutting cores for local modellers back then in the UK.

Joining core wings :

Dihedral angle sanded into each panel end.

Slot cut for plywood brace to cross the joint in its deepest section. A 3 or 4mm thick ply brace is more than enough with depth equal to the core depth. The ply brace cut to match dihedral angle.
"A 3 or 4mm thick ply brace is more than enough with depth equal to the core depth." - Depth of what? What is the core depth? Do you mean a brace the same height as the thickness of the core? Or going the thickness of the core into the wing?

My best guess is to cut a brace as tall as the thickness of the wing core airfoil but I'm not sure how far into the wing... Going back to my stick building days typically the center of the wing would have a ply brace the height of the top to bottom spar going out a rib bay or 2... I'm guessing this is about what we're going for?

Lightweight Glassfibre bandage about 2" (5cm) wide and length to fold completely round the joint.

Two part resin to fix bandage. (Old days we used Polyester for its quick setting - but it eats foam ! so the joint had to be sealed well before application). Laminating Epoxy would be safer.

OK ... how :

Epoxy join the wing halves with ply brace epoxied into its slot. making sure epoxy oozes out all along the joint to seal it. Scrape away excess before it sets. I used to spread it a few mm's either side of joint to be sure.
Once set and wing fixed .... then apply bandage with resin ... wetting out fully and sqeeg'ing to make sure fully contacted to wing skin. Smooth and leave to set.
Any thoughts on using polyurethane in the place of epoxy? I've been on a "keeping this thing light" kick with this build and have mostly stayed away from epoxy and hot glue because of it. I shouldn't have any significant gaps (I cut the dihedral angle using a jig on a table saw, got a perfect cut, I'm very happy with how that turned out), but even so, polyurethane (GG) should fill small gaps and should still be stronger than the foam I'm gluing to.

Viola as they say ...
For some reason that made me laugh... thanks
Silverback is offline  
 
Page generated in 0.04046 seconds with 8 queries