I have a composite wing stuck in the mold. It was well waxed, but its still sticking pretty bad. I was able to remove one half of the mold, but the wing is stuck in the other half and I'm really struggling getting it out.

Any help or ideas would be appreciated.

Dave,

Sorry to hear that. I'm still dealing with the fallout of some stuck parts.

It sounds like you will have to destroy the part. That is a small loss compared to the mold.

If you used Rohacell, you probably want to pull out the inner layer of glass, leaving some foam and one layer of glass.

Depending on how bad it is stuck, you may be able to use an artist's spatula to chip the paint/glass away from the mold.

If you can get the outer layer of glass out, chipping the paint loose is easier. I have used a 1/2" chisel to get the glass out. It is time consuming, but with care it can be done.

Worst case, you can ship it to me and Matthew and I will work on it.

Don Stegall
RCPRO

Try compressed air, and blow it between the part and mold.

soak it in warm water let the water get in between or perhaps a solvent that works on wax

I have not given up on the wing yet, I was able to get it out of one side, but the other is pretty stuck. I have one edge free, and will slowly work my way around the perimeter.

I know I did a diligent job of waxing, so this is really surprising to me. I tried compressed air, but thats not working.

I have a 8" long by 11/2" wide piece of 14 thou mylar with all the edges smoothes that I use for removeing parts that are hung up by using it like a feeler gauge and slowly working deeper under the surface .
It may not have been the waxing that was the problem different paint brands seem the same but react very differently when sprayed into molds.
Main thing with wax is dont polish it to a shine wipe it to a shine so that you dont rub off previous coats
Terry

I polished the wax good, that may be part of my problem. I did use differnt paint this time, some Concept PPG and Klasskote Epoxy paint. I've used them together before on planes, but never in the mold. I will give the feeler gauge trick a try. I am using bondo spreaders right now, they are just not long enough. I have the back edge started, but the leading edge isn't budging.

try with water... maybe is the only way



dapan

Dave,

If you can lift an edge, you might try dripping a few drops of lacquer thinner in there. The lacquer thinner will certainly attack the wax, and may soften the paint a little. Either way, I think it would work at least as well as water. You'd need to keep adding a little at a time, though, or it will evaporate out of there and you'll be just as stuck as before. (Maybe more so.)

Duane Gall
RCPRO

Wing is destroyed. Most of it is removed from the mold. I don't think the mold is damaged, but I don't have all the stuff out.

I am really surprised one side came out perfect, and the other stuck. I KNOW I waxed both sides.

Dave,

It can happen. I sprayed the Swee' Pea fuselage, Swee' Pea tail, Stinger fuselage and Smasher tail with epoxy primer. The Swee' Pea tail stuck and the Stinger fuselage stuck. Exactly the same preparation, and the same batch of primer.

I somewhat determined that the Frekote had expired and failed. But I couldn't figure out why some stuck and others didn't. The only thing I could figure is that the Frekote had actually stopped working, and I was getting good pulls because of existing wax.

If you did anything different to one side, it could have affected the side that stuck. If you used different paint on the two sides, even if it was the part before, it could have made the difference.

It is a shock when it happens. I was using 100 PSI air and a part just would budge. When I used a rubber mallet, I could usually tell when the part released, but not this time. It has me very jittery now.

Once I get the mold cleaned up, I'll just stick with PVA and a base coat of white. I can't take the chance with epoxy molds with stuck parts.

I used the same colors on both sides, so I am confused. The only thing I can think of that may have caused me issues is that I painted the molds and bagged the glass/rohacell/glass a couple of weeks ago, and just added the internals and sealed up the mold yesterday. I think I will try to do it all in a few days in the future.

The whole thing can be hit and miss to a degree, I have molds that parts have fallen out of since day one using PPG Detron paint and I normally do 2 to 4 pulls per wax then I tried a Spies Hecker paint which a so called expert said was the same and 6 hours of peeling and chipping later I had my molds back.
Dont know if you heat your molds but this can be a factor if not cured fast enough the resin can go through the paint a bit and bite onto the mold but if the wax does not like heat one half may have been heated to much.
I have tried about 5 different waxes to get to where I am now ,First was HiLo which was great but fish eye in the paint is a problem, I had problems with dolphin wax and it seems to be a resin issue but I like the resin to much to change and I am now back to a wax I first used 18 years ago and still the same tin K&H PLP10 which is brilliant for fuselages but using it on epoxy tailplane molds the part would always start to come out while joining so I use Dolphin on those molds to keep the parts in them for joining, But on polyester tail molds the K&H is fine.
Don I know some people who swear by freekote but I know three times as many who have had dramas and it is always a big surprise when it fails one half fine the other stuck forever.
Hope some of this helps
Terry