View Full Version : how to accurately measure gelcoat & hardener?

Kevin 89MC
05-14-2013, 09:36 AM
Any tips for measuring the correct amount of resin? I have a quart of resin, and the instructions say to add X number of drops per ounce of resin. I only need a small amount to do some keel repair. Tried to mix up some last night, and at first I didn't add enough hardener, as it never thickened up. I added a few more drops and then it went from a runny liquid to a nuclear hot blob in about 2 seconds, not exactly enough working time.

I don't think the wife would appreciate me using the kitchen measuring cups! I suppose I could go buy a measuring cup for resin only.

So that leads me to another question, is the "ounces" referring to weight or volume? Instructions don't really clarify. I'm assuming volume, but I seem to recall a how-to video showing someone measuring out the resin on a scale. Don't really want to buy a scale, and the bathroom scale likely isn't accurate down to the ounce.

Thanks in advance.

05-14-2013, 09:45 AM
They sell the measuring cups and pumps at places like west marine etc. I usually try to mix enough up that I can more accurately get a measurement. Know its wasteful but it leaves less room for error

05-14-2013, 11:11 AM
I use tiny plastic cups that have measurements on the side. I bought them from www.uscomposites.com. You might be able to find very small clear plastic cups at the store. Count out however many drops it takes into one cup and mark that cup. Then each time just squirt in the hardener to the line you marked (so long as you make the same size batch).