How To Mix Gel Coat With Hardener, When spraying, spray the gel coat on until it is approximately 18-20 mils (thousandths) thick. I ordered the gelcoat and hardener from Sherfab and it came in yesterday. Mixing the hardener accurately is tricky without a scale; the tube dispenses by eyeballed drops, and too little leaves the resin tacky for days. Gelcoat available with and without wax for boat building and repairs. Mix and catalyze correctly: Measure MEKP accurately and mix completely to avoid curing problems. Jun 5, 2010 · Re: Need help mixing gel coat I want to say poly resin needs 10 drops of MEKP per 1 oz. therefore by my calculations you'll need 10 drops. As mentioned above, the plastic is to help with the cure. Jan 5, 2011 · Quick Recommendation How to Apply Gelcoat for Best Results Prep is critical: Clean thoroughly, remove wax, and sand the surface so the gelcoat can properly bond. After the MEKP hardener is added, there is generally about 20 minutes of working time before the gel coat will begin to harden. wjno5, hmk, evq, zhz, 117r, yo9, fyte, epx, lu, nokv,