Custom tumblers have exploded in craft circles. Many people look for ways to take their projects to another level with paint, glitter, vinyl, or custom decals. After spending hours laying down epoxy resin, the urge to grab acrylic paint and add a final flourish can be strong. But it’s not always as straightforward as it sounds. I’ve had a fair share of sticky messes, mysterious bubbles, and surprising peeling, so let’s break down what happens when paint meets cured resin.
Epoxy resin cures to a solid, nonporous coat. It protects artwork, locks in decals, and gives that glossy look everybody wants. Painting on top of it can be tricky because cured resin is slick and doesn’t give paint much to hold onto. Most acrylic paints stick well to porous or rough surfaces, but they struggle on glassy ones. That’s why I’ve watched friends swear at a tumbler, only for beautiful designs to flake off by morning. The most honest advice I give fellow crafters is: treat epoxy like glass or ceramic. Paint won’t adhere the same way it does to raw stainless steel or unfinished ceramics.
I ruined my first few painted-over epoxy projects. Then I learned one simple trick: scuff the surface. A fine-grit sandpaper—think 320 or 400—can rough up the glossy finish. By hand or with a gentle electric sander, a few minutes of careful abrasion gives acrylic paint a foothold. Clean the dust thoroughly; any grit left behind becomes part of your design, whether you want it or not. Once the surface is matte and clean, acrylic paint grips it much better. Skipping this step means fighting every inch of the process.
Even with sanding, acrylic isn’t bulletproof on epoxy. Tumblers get handled, washed, tossed into bags. Plain acrylic scratches, chips, or fades fast when left exposed. The best tumblers I’ve seen at craft fairs either use specialty paints made for glass and plastics or rely on a final seal of clear epoxy. This topcoat locks paint below another resin layer, protecting it from keys, dishes, and dishwasher rides. Paint on top of the last layer of resin will wear away in days, not months.
Some crafters start using oil-based or enamel paints, hoping they’ll bite better than acrylic. This works about as well as acrylic if you keep the surface scuffed. Anything labeled “multi-surface” or “suitable for plastic, glass, or metal” usually wins out. I always seal finished projects under one more layer of resin. It seals in the design and leaves a perfectly smooth surface. Food-safe resin is a must for tumblers, since folks will take sips from every angle. Skipping a topcoat saves time, but nothing beats the durability of a fully protected piece.
Most people want their tumblers to last through daily use. All it takes is a few ruined pieces to learn that prepping the surface and adding a strong topcoat makes all the difference. DIY crafting is a learning journey. Those mistakes become lessons for the next round. Careful prep and sealing keep customers happy, cups looking sharp, and hands clean.
