Just curious,
Does Hardened (for a day or two) epoxy resin inhibit or retard the cure of Polyester resin? I just coated a FG part that I made with epoxy resin with Poly resin to give it a little more rigidity. The part had set for about a day and was sufficiently cured before doing this.
Just curious. I noticed that the resin in the cup had cured, and the little spots on the wax paper that had spilled were cured, but not the surface of the parts.
Thanks,
Curtis

Poly resins stays sticky until you cover it with a finishing coat. It doses this so the deferent layers will stick together. Just put a coat of fishing resin over it.

I'm not sure you know what I mean. I don't mean sticky, I mean liquid. It has set for about 6 hours and it is still wet. Like I said the other pools are set hard and will break in half when stressed, the parts that are coated are actually wet still.
Thanks,
Curtis

I don't know what type of epoxy or polyester resins your using however, Putting polyester over epoxy is a no-no. The other way around works if you have "sterlized" the part. ie. sanded with 80 or 100 grit and wiped with acetone
At this point I would get some Acetone or MEK and try to wipe it off as best you can, then put it in an oven, lowest heat possible (125) and bake it for at least 4 hrs to see if the surface will harden.
You will most likly find your epoxy part softened, baking it MAY bring it back to a usable condition.

That's what I was looking for. I wasn't sure about the compatibilities of them. I used some Devcon 2-part 30 minute to make it. Then I used Bondo Fiberglass resin with styrene (100-42-5) to see if that would stiffen it up again. It's not a big deal, they are simply covers for aileron servos for a little edf jet. I can go back to the drawing board and try it again. I will use that advice to "sterilize" the plug first, since I would still like to use that and that is made with epoxy resin.
Thanks,
Curtis

Whoa there! If I read you right youv'e got it wrong!
Take a second and reread what I was saying...
If you have a mold on hand and it is made of Epoxy resin. just wax it with mold release (I use Grignard' s Mold Magic) and layup your part from epoxy, do not use 5 minute epoxy and do not use polystyrene)! 60 min at the minimum; West Systems or the like is what a lot of folks use.
If your mold is made from poly you can use either epoxy or poly for the part.If the part is a servo cover you can use 2oz. cloth to make the part adding additional layers to get the thickness and strength you want or go to a heavier weight of cloth.
Do not sand the inside of the mold with anything heavier that 320 WD and then progress to 3200 grit.
If you have an existing part that you want to strengthen, then sand the inside if the part, not the outside and add additional layers of epoxy and cloth, again use 60 min or better epoxy.

You are welcome to PM me if you would like.

Brian

If you are making parts out of epoxy resin and fiberglass cloth, then you need to use FINISHEpoxy not 30 min or even 60 min. They bothe had thiskners added to them and make them harder to go through the glass cloth. West Systems is about the same thing, thin epoxy with no thickner added. You wet out the cloth and then let it set up over night. The next day, if you need to add another layer, do it then. Don't wait until it is compleately set up or it won't stick right. If you are using a mold, make sure yo uhave plenty of mold release on it or you will glue them together forever. Spread out each application of epoxy with some kind of spreader. Plastic, rubber, or balsa all work to spread the epoxy out and cover the part good. Wype up the excess and let it sit over night again. If you don't want to put any more layers of glass on, then fill the weve with a final coat of finish epoxy and use a spreader again and just fill the weave, don't lump it up all over the place or you will have much more weight then you need. Do your sanding the first day after it sets up if possible. Anything longer then 1 day and it starts sanding like cement.

Ed