I am new to using this product. I used it an ornate Prima silicone mould and now I want to paint over the decorations that I made using the resin. What type of paint product should I use? Or can this even be done? Any help would be appreciated!
I've only ever used paint on RC-3 but the Clear should act the same. Usually the best paint bonding is when you paint the mold with primer before pouring the resin. But you can paint the primer on immediately after the resin hits "cured hard enough to demold but still warm" stage. You can still paint it even after it's fully cured but the resin usually bonds better when the primer is painted on the mold before casting as the resin needs the heat of curing to bond the best with the primer. Either way you will need a primer layer - if you use the paint that has paint/primer then you can use that. Most any paint should work but an acrylic paint would work the best and it will bond the best when a primer is applied first if the paint doesn't already have primer in it. A clear primer will work just fine too just as long as it goes on before the paint.
I did a test on RC-3 where I sprayed a key chain I cast days after it had cured and it's on my key chain I use all the time so it goes in and out of my pocket and I don't take any care with it. I used Krylon primer/paint spray and it's mostly stayed on with a few spots were the paint rubbed off. If you can't paint the mold (easiest way) with primer before casting then you can do it after it's fully cured but be aware that you might have to repaint at a later date if it gets a lot of "rubbing" on it. Also you might need to do more than one coat - my key chain only got one coat and some of it has rubbed off.
Another possibility is using dye or paint mixed into the resin itself. I had good luck putting a few drops of Testors model paint (enamel) RC-3 or Alumilite White. I also went to the local paint store and had them computer match some plastic parts I'm doing reproductions of, and they sold me just the pigment. I mix a small amount of the pigment into the resin, and it works great. A near perfect color match, and no paint to mess with or chip or peel or flake.