BPO Hardener

I've used this for a few years and like using the black BPO hardener because it turns the white filler light grey when the two are mixed, which helps you make sure the two parts are properly mixed. I use it any time I don't care if the mixture is not white (which is almost always - the light grey is no problem under white gel coat, e.g.), then if I must have a white mixture I can use white BPO and all the mixing practice I've had makes me confident I've mixed as well as possible.

Most of the time I wish the mixture wouldn't set up quite so fast, so it would be easier to use on larger areas, but that just seems to be the nature of the product, no matter what company makes it.

The thing I really dislike about this is that the tube seems to fail way before using all the hardener. You have to knead the tube before using the BPO because it separates between uses. While kneading I had a tube fail at the point where the body of the tube turns toward the threaded opening, and I had a tube fail at the crimp. Each time I ended up with black fingers and the rest of the hardener in the tube was wasted. In fact, that's why I bought the tube that led to this review; the tube failed at the crimp.

Great service and product shipped out the next day!