I just glued 2 1/4" firewalls together to make a 1/2" firewall.

This is driving me crazy, it keeps sliding all over the place
even with C clamps all around.

When and took a shower only to come back and see it has slipped a little with the clamps on.

Any suggestions ?

L

Sounds like you have to much glue in there. That will probably always happen, especially with epoxy. They don't need to be clamped down really hard though, just lay down some way paper, slap some glue on them and set a paint can on top of them.

That a piece of scrap balsa and tack it to the fuselage side. Then clamp. After everything is cured, pin it with 1/8th" dowels though the sides.

Epoxy is the opposite of white/alaphiatic glue. Too much pressure and it squeezes out - starving and weakening the joint. I usually set the pieces on a flat surface with a piece of wax paper under them and set a lead weight (usually a ziplock bag with shot in it) on top of the stack. I just did one that was three 1/8" ply laminations and I stuck T-pins around the edges (into the base wood but not the pieces themselves) to keep them from slipping.

Well, the thing is that they were slightly nonflat hence the need for a little more pressure, it seems to be ok now that I had to watch it for the last 2 hours, it just has a hair of misalignment which I can sand off.

When that might happen, I always clamp them together dry, drill two 1/8 holes anywhere away from an important area, and use two 1/8 dowels to keep them aligned when gluing.

-David C.

now thats a good idea.Thanks!

I also use the dowel trick with great results! Got this idea from a GP kit suggested it.

align them dry , useing a small very small drill bit drill four small holes one in each corner, after applying the epoxy, use either small screws or if you build on top of a hollow core door like I do , push t-pins all the way down to take the warp out ,go have coffee, no problem .

Highlander