Fiberglass resin to hardener ratio

85 degrees out

What's the ratio?

Thanks

 

Not trying to be cute, Bob, but I've always kinda done it by feel - less hardener for higher temperatures. I don't know of a specific ratio, like there is with paint and reducer.

 

10 drops mekp


per fluid oz. Of resin. Should give you 15 min +- open time ,..

 

So, if I have 4 fluid ounces how many drops would that be?

 

Here's a chart... http://www.silpak.com/pdfs/MEKPRATIOCHART.pdf

Different companies, temp., humidity, age of the chemicals,thickness of the lay up all play into the "proper" ratio and work-ability . Start with a low ratio first.

 

4x10= 40. You 're kidding right ???

 

This can probably be adjusted for smaller quantities also:

 

The resin I bought from tap plastics uses half as much resin. For example: 2 oz of resin to 1 oz of hardener. 3 oz of resin would use 1 1/2 0z of hardener. It has a curing time of 5 hours. This resin can be used in 40 degrees weather & requires a longer curing time. The 5 hours curing time occurs in 80 degrees weather. The resin is epoxy resin.

 

I've found Epoxy Resin to be good to work, with easier to measure out for a start, unfortunately it doesn't play well with Polyester Resin. the job needs to be all one or the other. Haven't done any glassing for a long time now.
Regards,

 

The guy I buy my resin and fiberglass matt from has been running a fiberglass repair shop for decades. 2% is the ratio he uses.

 

That may have something to do with the brand involved . . . .

Here in the Caribbean, where there's a lot of marine fiberglass work done, everything is done with West System, which is epoxy based.

Generally, it's fine to use Epoxy over cured polyester, but not the other way around.

I'd follow the recommendation of the manufacturer of your resin, as far as mix ratios.

West has a couple different hardeners for different temp ranges, as it's often upper 90's here most of the year.

All epoxy resins have a much different ratio for hardeners than polyester.

West has different pumps for each product that dispense exact amounts to always get right mix. . . I should think other brands would also have a similar system

 

Yeah Agree, West is a good system. The job I had delaminate was Epoxy over Polyester.