Dave H wrote:
Has anyone tried putting on the final finish to a project using an
airbrush as the application tool for either water based or oil based
polyurethane? If so, any recommendations on brand and model of the
airbrush?

For what project?

Airbrushes are fantastic for models, small instruments, small toys,
figurines etc... where very thin coats are required so details aren't
obscured. An airbrush sprays an even finer coat than a typical spray
bomb, so more coats are required to build a decent finish thickness,
which isn't usually wanted or required where a typical airbrush is the
best tool. Most airbrushes are also limited to about 2 oz. of finish
per filling, further limiting the project size.

That said, if I'm choosing the airbrush to spray a clear top coat, I'm
also choosing lacquer or shellac, for a fast, dust-free coat and very
thin "shell". All in all, I really don't know how polyurethane varnish
would spray with an airbrush. G On the other hand, oil-based
polyurethane is sold every minute in spray bombs, so I don't think it
would be a problem if properly thinned. Water base polyurethane might
be more difficult.

When we're talking top coats, even something as small as a typical
electric guitar body is usually better sprayed with at least a
"touch-up" gun.