I'll tell you the fail safe way. What I have found to be a successful way to make a plug of a canopy without doing damage to the original is this:
1. Mask off the entire outside of the canopy with 3M blue tape.You're doing this to keep your sticky finger prints and whatever off the canopy.
2. Wax the inside with partall #2 release wax. Wipe on and buff off a couple of times is fine.
3. Spray the inside with partall #10 PVA release and let dry for a few hours.
4. Using epoxy resin and SLOWhardenerand brush a coat on the inside surface and let it start to cure . It takes an hour or more, brushing it occasionally to pop any small bubbles that form. All this is to have no heat which you will have with a fast application.
5. As the first coat becomes tacky I apply a 3 or 4 oz. layer of fiberglass cloth and more resin, then a 6 oz. layer and let dry overnight.
6. This first shell will be strong enough to pull right out the next day but because you kept it thin, there was no hi heat build up in the curing process that would wreck the original canopy.
7. Now that you have removed your plug and put the original canopy in a safe place you can mask the outside of the plug with 3M blue tape to keep it clean.
8. And now wet the inside with new resin and lay another 5 or 6 layers of 6oz or heavier cloth wetting them one layer at a time to build up the wall thickness and you will have a strong stiff plug that you can now use on the Vac U Foam machine to make new canopies.
or you can send it to us and we will do it for you.