Will SW ProClassic self-level if brushed on a vertical surface?

Howdy All. For context, I've built a window jamb extension out of poplar, and it's already primed and brushed with one coat of ProClassic. Now I'm trying to figure out if I should (1) apply a second coat before I install it, then fill the holes and apply touch-up paint; or (2) install it first, then fill holes and apply the second coat.

If I go with the first option, my only concern is that the holes will remain visible after touch up.

As for the second option, I know a lot of folks (e.g., the pro-painter types) like to paint trim after it's been installed, at least the final finish coat. But I think most of them are spraying, and I'm brushing for now. Not sure if that makes a big difference, but I still worry that the paint won't properly "self-level" on a smooth, vertical surface, or that it will run.

What little instinct I have tells me to apply the finish coat first (on horizontal surfaces), then install, and then just deal with the nail holes (only about 2 to 3 total). I'd rather not have to apply masking tape on my new vinyl windows, if I can avoid it.

What would you do? Your experience is appreciated.

Yasha

Either way works, but the nail holes will be less visible if you install the trim after the first coat of finish and apply the last coat once it's up. It will level just as well on a vertical as a horizontal surface. I recently had to finish the side of a cabinet that could not be removed. I thinned ProClassic with about 3% water and 3% BM's Extender and applied it with a fine nap mini roller. It looks like it was sprayed on. I did some door jambs with the same mix using a foam brush. Just as nice.

Practice on some scrap until you are satisfied your process meets your expectations.

John

It won't self level with a brush unless thinned a little. Touch up will look much worse than final coat in place. John is the Man on thinning, so I would bet you can't go wrong by following his advice. I just eyeball it, but I mostly spray anyway, and not so it needs thinning.

Don't paint until you are sure the holes won't show. Paint won't fill anything. I haven't found the ideal filler yet, that doesn't shrink before drying. If you are sanding through the previous coat, and leaving anything that doesn't look like a flush, round little filled hole, you probably have sanded too much.

The last room I finished, I sprayed the walls, and trim together, all white semi-gloss ProClassic white. The owners used to call it their Sunroom. Now they call it "that room you painted".

Alright, just picked up some SW M-1 extender. Hope it works alright. Will report back.

Just thought I'd post a quick update. I painted the sill and head before I installed, so I could paint on a level surface, and thinned with a touch of water (without extender, as there wasn't a lot of surface to finish). The final coat turned out beautifully.

As far as wood filler goes, I did a test piece using four products I had in the shop: 3M patch+primer spackle, Crawford's putty, ordinary joint compound, and last of all Durham's Rock Hard. IMO the water putty worked the best, as it sanded extremely smooth.