I want to make a board with polyester resin, but I'm not sure what additives I need.

To harden (= polymerize), polyester resin requires a catalyst. You can choose to use two types of catalysts: a liquid PMEK catalyst (classic), or a UV catalyst which allows you to increase your working time since the polymerization will only take place when your board is presented in the rays of the sun.

• The PMEK catalyst is generally preferred. It allows rapid polymerization of the polyester resin. Depending on the ambient temperature of your work room - never below 16 degrees, and preferably below 30° - add 1 to 2% of catalyst for your resin to gel in around 15 minutes. Warning: less than 1% and your resin could never dry completely and make sanding impossible; more than 2% and you may not have time to properly complete your stratification. Follow the instructions carefully!
• UV catalyst can replace PMEK. It allows the polyester resin to polymerize by exposing it to UV rays from the sun, or those from UV lamps (recommended wavelength: 364nm). Infinite gel time as long as the resin is not exposed to sunlight; it is therefore an ideal alternative for “stress-free” laminating. Be careful not to work in a room exposed to light, otherwise the resin will harden prematurely during your work.

Paraffinized styrene must be added at 3% during the “hot-coat” stage. It allows sanding of the resin.

The styrene monomer allows it to fluidize the resin for “finish coat” / “gloss”, or when the resin is a little too thick.

Updated on: 04/01/2024