Painting - painting woodwork and trim

I am painting multiple rooms. Needs two coats. I use liquid sander then flat latex paint for first coat on woodwork, then go back later with a coat of latex enamel semigloss. I'm not sure what kind of paint is on the wood already (oil vs. latex); it is very old. Am I getting into trouble here? The woodwork has grooves and other decorative things that make it too hard to sand by hand (not to mention my sore wrist). Also when I paint with the enamel paint, it gradually clumps on the brush and I have a hard time washing it all out, especially on the tips of the brush hairs. Is there anything I can do to prevent this?

Useing latex dirctly over oil based paint is a definate no no, after the de-glosser you need to prime with an oil based primer/undercoater such as kilz before applying paint. Test the existing paint with Goof-off (paint store) on a rag, if it starts removing the paint then it is latex, if it does not then it is oil based.

As far as the buildup of paint, are you letting the brush sit out of the paint for any lenth of time, allowing it to start drying on the brush? You can also thin the paint a little and use the least amout of brush strokes as possible to leave the paint covering good and smooth.

[Edited by Chipfo on 02-21-01 at 01:59]