What materials can I use for an epoxy dam that won't stick?

Epoxy bonds to most materials, so only a few surfaces reliably release without sticking:

- Epoxy tape (Tyvek tape) applied over a rigid backing such as a 2x4 or wood trim. The backing matters: the tape needs something solid behind it that won't flex, and the wood must be completely covered so no bare wood touches the epoxy. - Silicone caulk, for sealing the seams of a temporary dam. Keep it off your work surface, since epoxy has a hard time adhering where silicone has been. - Silicone molds, and rigid custom molds made from HDPE plastic. - 4 mil painter's plastic, for covering areas you don't want epoxy on.

Don't use packing tape or other general-purpose tapes as a dam. For temporary dams we only recommend epoxy tape and silicone caulk.

Our epoxy tape is Tyvek tape. We don't know whether Tyvek makes more than one type of tape, so if you buy it at a hardware store, test it with the epoxy first, or order ours to be safe: https://www.bestbartopepoxy.com/collections/tools-supplies/products/epoxy-edge-tape

For an organic or curved edge, we're not aware of any material like plasticine or playdough that can be shaped by hand and won't become part of the finished piece. That kind of edge takes experimentation with custom forms made from the materials above.

How to build a dam: https://ultraclear.helpscoutdocs.com/article/223-temporary-dam-epoxy