What is a good method of cleaning and etching a brass car before painting?
Best way: sandblasting with baking soda.
Good way: soak the model in a paint-stripping solution (ELO, brake fluid, etc), scrub off the paint. Repeat until all old paint is gone. Wa***he model with warm water and Dawn. Once dry, pickle the model with white vinegar for a few hours. Rewash.
Orsonroy
I do all of the second part of your reply,but I have not used the baking soda method,just the grit that came with the sandblasting gun that I got from micro-mark.How well doe’s it work? I would imagine that it’s fairly gentle on the brass.
All I ever did was get off ALL plastic parts, soak in laquer thinner, slosh off any varnish left, dry it, and hit it with either Floquil primer, or engine black eased with a tiny bit of white. Haven’t done any brass in awhile, but the Scalecoat II has given excellent results on plastic so I would have no problem using that either.
(I hate to be immodest, but my brass painting efforts were first class on all counts, and had held up for 20+ years when we parted company. I will add that they were all only black steam engines, except for the N&W red stripes where appropriate. I envision some diesel schemes would be rather difficult.)
Baking soda works really well, because it’s generally a finer grit than most blasting media, and so won’t harm finer model details (as fast). You end up using more of it than regular media, but it’s cheaper. I picked up the trick from an old issue of Mainline Modeler, and generally don’t use normal grit any more.