Finishing Processes for Polyester Resin?

Hi all!
Anyone have any information about finishing polyester casting resin?
Can it be sanded/sandblasted/polished/etc?..

Cheers :laughing:

Yes to all of the above. It usually has a waxy feel to it out of the mould. You can sand it roughly to shape, then move to wet and dry sandpaper and then plastic polish to get a high polish.

You can sandblast it easily, but you’ll need to seal it if you want to avoid finger print marks. (like a clear spray paint)

The better the finish on your mould, the less finishing you have to do to the resin. Also, the longer you leave it in the mould to cure, the less waxy it feels.

ive done quite a bit of work with this material. if you can buy red blue and yellow smooth-on tints you can create just about any color you desire. i also like the smooth on dragon, not the dragonQ silicon which cures too quickly and allows air bubbles to adhere to your piece if you dont have a pressure pot handy. i like castin’ craft clear polyester resin but their catalyst is terrible and takes forever especially if you add color so go to autozone or wally world and buy the bondo resin catalyst (clear liquid). ive been adding 35 drops of catalyst to 2 cups of resin + 2 drops of color. if you have a two part mold this will help a lot. after pouring in the resin it will become a gel where it will hold its shape but still be flexible. at this point you can remove the top portion of the mold to improve curing times which can be up to 3 days. if you want to speed up the curing process even further heres my toaster oven method: let the cast resin piece cure for 3 hours, set toaster oven to 225-250 degrees and put the resin piece in there on the metal tray for 5-10 min. the resin piece will come out hot and flexible so you have to be careful as it will deform quite easily, you can put the casted piece back into the mold to cool to prevent it from deforiming if neccesary. the longer you let the resin piece sit around and cure the less finishing work you have to do since the outer mm of resin never fully cures and its a pain to sand off. if you have large air bubbles dont fret these are easy to fill in with plain clear resin and you dont have to worry about matching up colors, if the bubbles are small use CA glue like Zap a Gap. i use files and sandpaper to fully remove the flashing and finish the pieces. after you get to 600-800 grit sandpaper you can put toothpaste on the resin and run it under a cloth polishing wheel which gives it a nice shine. here you can mask off parts with tape if you want to sandblast any specific areas that require texture or grip. then i use paste finishing wax by minwax. it says to let it dry for 10-15 miniutes but dont, wait 2 min then polish it with cloth or paper towels. hope this helps you out.