Oberfeldwebel

If I use a plastic (Tupperware-like) bowl as a female mold and try to make a cowl, would it be necessary to wax or use some release agent on it. It seems that the fiberglass and epoxy would not stick to the mold much like using flexible plastic lids to mix epoxy on. True or not true?
Anyone do this?

dreadnaut

My Feedback: (5)

I hadn't thought of that, but it makes sense. I had one that would have made a great GeeBee R2.

KC36330

I've used them many times and always apply a light wax coat, it makes the release easier but it will release without the wax.

Ed Smith

Whenever I want to use a new idea with glasswork I always test it on a small unimportant piece. This has saved me a lot of heartache.

Ed S

SCALECRAFT

My Feedback: (13)

Yep it works. You just may have to destroy the bowl to get it out. .

Its a curse, now you will look at everything as if it could be something you can mold for modeling.

Rule 1, get permission form your wife.

Steve

Oberfeldwebel

I bought a cheap set ($2) of these containers at Target for myself. Actually, I mentioned what I wanted and it's use to my wife and she asked if she had any bowl/container I could use. She's been very good about my hobby, buying me kits to build and asking if there's anything I need.
But, anyway here's a couple of pics of my attempt and I hope I don't end up destroying the "mold". I need 2 cowls for a B-26 I'm fixing up and think it'll work.

SoarLA45

Apply two coats of wax, then buff with an extremely clean cloth. Then, apply a thick coat, let it dry a bit, and buff again with a very clean cloth. Then apply a thin final coat, and buff. Then you can go on and laminate. Better than not waxing and having to destroy the mold (and possibly damage the part or destroy it completely).

Oberfeldwebel

My next attempt I will wax the mold. I didn't on the 1st attempt and in all fairness the epoxy was not completely cured some when I pulled it out, it looked like this. Not the least rigid or smooth all over.

KC36330

that looks like it was laid over a plug not inside a mold, if that was from inside (as pictured in your above post) you've got problems that waxing ain't gonna help.........

parrishairx

My Feedback: (77)

It is best to always wax your mold...use mold release wax for best results...automive wax is not made to withstand the clemicals..and sometimes the resin will bleed thru...to help the glass stick to the corners and curves mix a small amout of the resin mix with cotton flox or cabasil to thicken it up and put it on the edges before you lay the glass on..best to use several layer of a light cloth(6 oz. max) than a heavy cloth in 1 layer(do not use mat)..you can also cut the glass on the bias..at about 30 deg angle in 2" strips and overlap about 1/2" and put several layer on and you have a good part..only put enough epoxy to wet it out don't paint it like a house..

NCIS

That can't have been on the inside. When I was younger making boats in molds the whole purpose of a smooth mold is so the part comes out perfectly smooth. Also I gelcoat the mold after using Evercoat Mold Relase which aids in curing gelcoat and the glass. Then the part pops right out with a small amount of air from my compresor. The Gellcoat is white or whatever you want so you could make your part ready for install if the gelcoat matches the plane. If the mold is smooth you shouldn't have to do any sanding.

Barry
www.canopyrailsforwarbirds.com

Oberfeldwebel

The reason the part looks soo bad and it was....I tried to pull it out of the bowl way too early the epoxy hardly was set, so it was my fault that it looked that way. I was just interested in seeing if the bowl would work as a mold.

NCIS

OH, that explains it. Well at least you know it works. I need a tuperware bowl the size of a small trass can for the cowl on my 124.5" Corsair I'm building. Anybody got one 14.5" in diameter?

Barry

Avaiojet

Barry,

I strongly believe you would be better off making a cowling out of pink foam. This way you can control the shape. Poly or epoxy resin can then be laid over it and the foam can be melted away leaving the glass cowling. I used this method for this 1/5 Gee Bee Z cowling.

There are Threads about this method.

Good luck.

Charles

PS. I can do the graphicxs or masks for that size model.

www.cfcgraphics.com