Here Goes...
Hello Steve,
UCAT's and PCAT's are *very* difficult and temper-mental products to use, but since you asked... Yes, UCAT's (User Catalyzed) or PCAT's (Post Catalyzed) lacquers require YOU to add the catalyst, or sometimes it is added by the company when you purchase it. The pot life varies by product, some are very short.
Catalyzed lacquers offer a lacquers ease of application coupled with a better overall durability, like that achieved with a varnish. I use several brands, depending on what I can get at the time and whether I need a pure clear, or can get away with a finish that will yellow slightly over time. On medium colored timbers and darker, the yellowing products can actually enhance the overall color on some timbers.
Sher-Wood T77C30 gloss is a good product. You have to seal it first with a vinyl sealer for best results. You get less than 30 days pot life and small batches are not easy to mix up. I also like Duravar (Amber) and Krystal (Clear) by ML Campbell. Sherwin Williams has some really good products, also Lilly and Len Mar have some nice products. Reducers vary by product and your need, so check before buying.
I prefer to spray my finishes whenever possible. On something small like a pen, I use a fine artists airbrish. I also have a large HVLP rig for larger projects like my Grecian wine and water vessels.
Yes, I spray my epoxy finishes. It's a bear to do and I do not recommend it unless you are prepared to toast a few airguns to get the process down pat.
I thin my epoxy with Acetone, or White Vinegar to reduce it to an acceptable viscosity. Once applied, I turn the finished barrels for several hours at approximately 5-10 RPM until the epoxy has cross-linked. To keep the barrels turning, I use an old BBQ rotisserie motor and a handmade mandrel assembly.
I use West Systems Epoxy (WS) and also System Three (S3), depending on my need and the color of the underlying timber. I like the Clear Coat product from S3, as the base and hardener are crystal clear. I've used another product that's made for surfboards, but I cannot recall the name at the moment. Seems like it was a WS product???
You can wipe on the epoxy, but it will not "lay-in" as well as when you shoot it. The constant rotation is necessary to prevent runs, drips etc; as the epoxy cross-links. You have to learn to shoot FAST and clean your gun IMMEDIATELY, or you will have a nice piece of metal art for your troubles!
Nothing can interrupt this shooting and cleaning process, or you need a large supply of spray guns on hand and a "Gawallup" of cash in your back pocket. Don't ask me how I know this...
So, if I haven't scared you away yet... I'm planning on writing an article on my advanced pen finishes, and will also add it to an upcoming DVD video. I'm quite surprised though by the number of turners that have emailed me about these finishes. They are way too difficult for 99% of the turners out there, IMHO. Take care and all the best to you and yours!