Step 5 of the process
Demold and finish
Demold when the resin is hard, wet sand sharp edges through the grits and bring back the gloss with polish or a thin top coat. Clear epoxy softens at about 108 to 130 F, so it is not for hot pans.
- Sanding
- wet, 400 up to 3000 grit
- Gloss
- polishing compound or a thin resin coat
Peel the mold away from the piece rather than pulling the piece out of the mold. If the resin flexes or takes a fingerprint, stop and give it another day. Sharp edges and a raised rim where the resin met the mold wall are normal and come off with sanding. A face that came out dull or hazy is covered in why resin turns cloudy.
Sand only fully cured resin, and sand it wet: water keeps the surface cool and the dust down. Work up through the grits without skipping, 400 or 600, then 800, 1000, 1500, 2000 and 3000, and finish with a polishing compound. A thin coat of fresh resin over a sanded face also restores the gloss. How to sand and polish resin has the steps and the polishing kit guide the supplies.
Know what the finished piece can take. Data sheets for clear epoxy put the heat limit at about 108 to 130 F, so a hot mug can mark a coaster; the heat resistance chart lists the figures. All clear epoxy yellows slowly, faster in sunlight. For food contact only the maker's own statement counts: see is epoxy resin food safe.
Ready to move on when: Edges are smooth, the surface is clear or evenly matte as intended, and the piece has had its full cure time before use.
Common mistakes at this stage
- Dry sanding and breathing the dust.
- Skipping grits, which leaves scratches the polish cannot remove.
- Putting a piece into use before the full cure.