Two-Part Foam - How Tough Is It?

I have been kicking around the idea of using two-part foam for the creation of leading edges for LPR/MPR rockets.

I understand that there are different weights, etc.

I would like to know two things:

1. Is is robust enough to be used at all (as in withstand moderate thumbnail pressure without deforming)
2. If "1" is true, what would the recommended range of foam to be used

I would use the foam in conjunction with a mold to form the LE, and possible the TE as well.

Greg

It is soft, has large bubbles that would need filling, and makes a huge mess when you try to apply it to the outside of anything.

I wouldn't use it on any external surface with a radius of curvature smaller than an inch or so.

The foam I use isn't what Id call soft when cured, its pretty hard with a fairly fine structure - no big bubbles I've noticed, but then I dont cut into it very often. I've not tried it, but I saw somewhere using foam to shape Nike style fins (though I think this was using the home depot spray foam, which is nowhere near as strong/hard as the 2 part stuff I have)- the secret was to glass over it after you put it on. Seems like a fair idea to me.

Not strong enough for any edge. Ive seen rocket with no epoxy on the fins/ fincan only held together with foam fly on an O motor

You are better off using Bondo to mold or shaping surfaces.

I built a rocket using pre-glassed tubes from PML.
The nose cones base had to be extended to match the OD of the tubes, due to the glass wraps.
I used Bondo to close up the gaps. It worked like a charm! I painted the rocket, you can't even see any differences.


JD