Catalyst is an essential element to most processes in our business. Without the catalyst, no chemical reaction takes place and you might as well just pour water over your fiberglass or table. You would think catalyst would be an easy product to work with, and sometimes you are right, but you have to follow the directions exactly. It’s not pretty when you don’t (trust me).
MEK-P or Methyl Ethyl Keytone Peroxide, not to be confused with Methyl Ethyl Ketone, a solvent, MEK-P is one of the most common catalysts. MEK-P is used for polyster and vinylester style resins. It is very specific on ratios and requires the most attention.
Vinylesters require a hotter catalyst we sell, called Norox 925, sometimes referred to as “High-Point 90.” It’s a hotter catalyst that works better for the Vinylester. You will also see Vinylester requires a ratio of 2% by volume, as opposed to gelcoats and resin which are closer to 1.5%.
Gelcoat and Polyester resin, including Boatyard use a standard catalyst, or the 925 catalyst. These resins only require about 1.5% catalyst and are quite specific on the ratios, especially in hot weather. You will also use the same ratio’s for Polyester-based putty, like our OEM Super Poly Fill, or our gelcoat putty.
B.P.O. or Benzoyl Peroxide is a cream hardener that is used for most Auto Body and Bondo-like putties. It’s a bit easier and more forgiving on the mixture and comes in Red, White and Blue. The ratio is 1-1 oz tube per quart, or a 4 oz tube per gallon.
Epoxy activators are all proprietary, depending on the product. They range from a 1:1 ratio, like with our Table Top Epoxy, to our standard laminating epoxy allowing a 1:1, 2:1, 3:1, 4:1 and 5:1, allowing for different ratios that effect hardness and gel time. With different ratios, the higher the ratio, the quicker the pot time and the harder the epoxy.
With all these activators, sticking to the ratio is key, so if you were planning on eye-balling it, may I suggest picking up a couple of mixing buckets, or a squeeze bottle and take the guessing out of the equation.