The RAKA blush free hardner is great. I used it on all my glassing this winter. Good medium speed, cures down to 40 °. ... and no blush, and pretty good pot life. I don't think it's quite as thin as Matrix but not by much. I usually heat my epoxy prior to using anyhow which thins it down a lot. The RAKA fast and slow hardners are OK but nothing exceptional. The fast blushes a bit. I use it for all my small chores.

You certainly can't beat the price. By the way I've used System Three, West, Matrix, Chemical coatings and Evercoat.

I'll never use anything but a blush free for my large glassing again. It takes all the anxity out of recoating, filling the weave etc. I still re-coat in the "green stage" but knowing it's a no blush epoxy is great reassurance that you're getting a good chemical bond between coatings.