So, what do you use the epoxy brushes for? For that matter, how helpful are epoxy cups? Is the idea to pour the epoxy into the cups, then mix and apply with the brushes? Myself, I've always made two small piles of epoxy on flat cardboard, then mixed/applied with a balsa stick or cut cardboard, depending on the application size/shape.
It's mostly useful for brushing thin epoxy for fuel-proofing purposes.
Mixing it in a cup can have some interesting side-effects - like the tendency to self-heat, to the point it boils and sets itself off in 1/4 the normal time! Some types are worse than others, but beware this effect, particularly when using "finishing" epoxy or need a long working time, like sheeting a foam wing. In those cases, I mix up much more than needed in the cup (required for accurate measuring), mix it very thoroughly, then pour it out in a puddle on a sheet of aluminum foil. That keeps it from heating itself up too much and starting to cure early.
The best thin epoxies I have found for not self-heating in the cup are Aerospace Compositites "EZ-Lam" 30 and 60 minute types. Pot or puddle, it's about the same, and never catches you unaware. The worst I have ever found (for this characteristic, although it's good otherwise) is PIC Coating Epoxy, last time I used it, at about 80 degrees ambient, it boiled in the cup, then melted it! The hardener also catalyzed it's way out of a heavy polypropylene container, and also one of those waxy plastic disposable food container. Bob Smith 20 minute "Finish Cure" got so hot in about 15 minutes that it was uncomfortable to hold on to, just a few weeks ago, and set up hard in about 1/2 hour, while the same stuff brushed to an airplane took a good 8 hours.
Brett
Topic: bulk brushes (acid epoxy) (Read 781 times)
