My friend can buy polyurethane epoxy from his workplace for 3 dollars a litre, except that he doesn't know precisely the data sheet for it. His factory gets it in 20 ton deliveries.

He says that the mix has to be around 99% Polyurethane, 0.2% cobalt, and 0.8% of a toxic transparent catalyst liquid.

It's a generic industrial chemistry used everywhere, and can be mixed roughly by eye to achieve different drying speeds.

Do you know what the name of this resin system is called and where i can find precise information on it? What is the catalyst?

  • 2
    $\begingroup$ If the final product is polyurethane, than it is not epoxy, those are totally different chemicals. If you are sure it is polyurethane, have a look at wiki for the introduction: en.wikipedia.org/wiki/Polyurethane And to be sure, check the sheets of the delivered chemicals. Even if it comes in 20 ton containers, it must always be accompanied at least by material safety data sheet, where everything is described. Without closer info it is difficult to tell more. $\endgroup$
    – ssavec
    May 29, 2015 at 5:53
  • $\begingroup$ Hi, i'm doing some research. The resin is unsaturated polyester resin, using methyl ethyl ketone peroxide (MEKP) as catalyst, cobalt octoate (Coct) as an accelerator... The products are generic and don't come from the same suppliers necessarily. Already we have tell more :) $\endgroup$ May 29, 2015 at 7:38

1 Answer 1


The resin is the same variety commonly used to produce fiberglass baths, boats and many other uses.

The resin is unsaturated polyester, using methyl ethyl ketone peroxide (MEKP) as catalyst, cobalt solution for example cobalt octoate (Coct) as an accelerator.

It isn't often sold to consumers because it is too explosive and corrosive, the MEKP reacts explosively with raw cobalt, and it's dangerous to the eyes, it can cause blindness in 15 seconds if splashed in the eye.

The MEKP doseage is 1-2% per volume of polyester, depending on desired drying time. The cobalt is mixed first and dyes the polyester a whiskey color, you can dose it by color, the darker whisky color the faster it will dry.

Industry standards are 1% and 6% cobalt solution, 1% is dosed at 0.5% to 2%, however there is no way to tell without the product data sheet if the cobalt solution 1%, 6%, 10%.


MEKP and cobalt mix = flames MEKP in eyes = blindness wear goggles and rinse with water and go to hospital if you get some MEKP eye contact. wear protective clothing and avoid skin contact.

"Cobalt octoate is the most reactive and most commonly used paint drier. Cobalt octoate catalyses the oxygen uptake and accelerates peroxide formation causing a surface film to form rapidly and hence known as oxidation catalyst. It basically a metal caroxylate used to accelerate the drying process like linseed oil. It accelerates the decomposition of the organic peroxide initiators (often called catalysts) and promotes the cross-linking of polyester resins. "

Note that baths are finished with a gloss product called gel coat.


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