I feel I'm a fairly experienced painter (always done my own home painting) and just recently tried the SW Waterborne Pro Classic Semi-Gloss. It's okay on trim, but I have a really hard time painting doors with it. It drips and sags on me.

I'm painting old stained 6 panel wood doors white. Here's my prep: wood patch nicks, sand, degloss, 2 costs SW PrepRite primer, light resand, Pro Classic Semi-Gloss. I'm using a Corona 2" Chinex brush and feel that I'm applying a thin coat. I've even tried a tad of Floetrol in the paint-doesn't help. As I paint, I'm constantly going back to dab small drips and then the sags start and I just leave them to dry, then sand them flat and start all over again.

Am I doing anything wrong? Does it just take practice? Any hints? Maybe it's the semi-gloss and the satin is easier to work with. I'm using semi because it matches some other woodwork which still looks good and doesn't need painting at this time.

If I can't get it right, I'm just going to use Superpaint, which yields good results for me or Duration. (I have an immediate family member who works for SW (great family discount!) and the store is a mile away, so that's the paint I use).

Thanks!