Gelcoat Hardener

[Croixboy]

This is probably a stupid question ... Will the amount of hardener mixed with gelcoat effect the cure time, strength of gelcoat (hardness), or both?

 

[DaleH]

Yes, yes, yes. All ...

The amount of MEKP (Methyl Ethyl Ketone Peroxide) hardener for gelcoat and polyester or vinyl ester resins is typically added at a 1-2% ratio of hardener by volume. I use the 'drops per ounce' method myself for gelcoat.

Regardless, the amount added is also highly dependant on the ambient temperature. Too hard will cause it to be brittle, too little and it may not cure, harden, or skin-over properly.

 

[DaleH]

P.S. - if you don't know .... there is NO such thing as a stupid question. I always learn a lot as I'm never afraid to ask "Why?" or "Why not?"

 

[Porkchunker]

If you look at my old Gelcoat A to Z thread, I believe it was 12 drops of hardener to 1 oz of gelcoat material.

Dave

aka

 

[Porkchunker]

Here is the link: http://www.classicparker.com/phpBB2/vie ... 79&start=0

and yes...it was 6 drops per 1/2 oz or 12 drops per oz.

Dave

aka

 

[DaleH]

and yes...it was 6 drops per 1/2 oz or 12 drops per oz.

... depending on temperature though ... that is key!