SeamusG

I have a Great Planes Extra 300S 60 size kit. The parts are die cut. There are plenty of pieces of lite ply that are warped.

Question:Straighten these things before assembly? Or, use the assembly process to straighten them?

What pieces? Fuse sides, fuse top, fuse bottom, fuse doublers, formers, pretty much most except the wing ribs.

TIAfor you input.

Safe New Years ALL!

MinnFlyer

My Feedback: (4)

As you interlock the parts, they will keep each other straight.

Nothing wrong with removing some of the warp if you really want to, but it's not really necessary

SeamusG

I'm not real confident of that Mike. There is easily 1/16" or more slop in the "keys". Not anywhere near as tight as laser cut material. I have to use clamps to keep the pieces together. Yes, I have touched up the pieces with a sanding bar (surface and external edges only) but didn't touch the inside of the keys.

With this kind of slop, what glue do you recommend. The plans are exclusively thin & medium CA. Thinking Titebond.

jetmech05

Use elmers white glue....strong as can be...but takes a while to dry.....

Gray Beard

My Feedback: (-1)

The CG Cub I have on my bench now is one of the worst die cutting jobs I have seen in years!! The fuse is all light ply and it did have some warp. As soon as I clamped the two halves together at the tail and started installing the formers all the warps went away. I did require clamps to suck in the sides as I installed the top and bottom.
Rule of thumb for me has always been to use epoxy for ply to ply gluing. In this case the clamps got everything so tight thin CA worked great. As I got closer to the front of the fuse and had some bigger gaps to suck in with the clamps I used epoxy. The front part of this fuse is the higher stress area and it's a float plane, I don't want the fuse to come apart during those rough wave days.
I use a lot of wood glues but not on planes. I have gotten warps in sheeting every time I have used it. Other guys swear by it, I have just had rotten luck with it. Give it a try and see what you think, it may be you next favorite.
Gene

MinnFlyer

My Feedback: (4)

With this type of construction, the die-cut parts will force each other into alignment.

So Edge "A" will keep Edge "B" straight and vice-versa

LargeScale88

When I built mine, the parts were warped pretty bad. Like Mike said, the way the construction is on this airplane, the parts will "cancel" out the warp, as long is the first 2 pieces you put down are flat on the workbench.

I'm not sure its possible to get warps out of lite ply. I've never tried.


Jason