Zinser 123 - oil or latex?
 

I need to paint window sills and a door frame in a house built in '64. All of the woodwork seems to be varnished/shellac or stained and polyurethane. I'm not sure how to tell the difference, although the door frame is very glossy...the window sills aren't as much, but that could be due to the constant sunlight.

At any rate, I assumed that scuff sanding and Zinser 123 latex would do the job, but the BM guy looked surprised and said I should be using the oil based, even if the topcoat will be latex.

The latex based of Zinser 123 states that it will bond to glossy surfaces (as does the oil based). I did try the latex based on an old door (after scuffing) and it seemed to stick fine. But of course, I want to do the job right.

Which version should be used in this case? If the oil, will the latex top coat be ok? Any other advice welcome also.

Also, any recommendations for what type of caulk to use for door casing and baseboard? I assume I'd need something that remains flexible. The BM distributor has a lifetime Acrylic Urethane caulk that they recommend. I also have a few large tubes of GreenGlue Sound Sealant (for soundproofing) that is supposed to remain flexible. TIA!

Hey Bob- A q that is always an important one- how to get good adhesion.
First- scuff sand ( sounds like you're already on it), then I'd wipe down with a TSP substitute ( because they don't need rinsing) or even denatured alcohol. Gets any oil/ grime off while taking the sanding dust off too.
Then I think Z's 123 is about as good as any oil for adhesion. There are times when I use other primers like BIN or cover stain, but this should work.
Also understand that it takes a while ( maybe even weeks) before it comes to full grip and hardness. It is not always a good test right away. Even a day or two can make a real difference in how much it develops it's grip.

Good question!

This is just me, so don't take this as gospel.......when dealing with older woodwork I almost always use the oil. That way I am ASSURED that it will block the tannins in the wood from leeching out and staining the new paint film. To me the latex stain blocking primers are not nearly as effective at blocking out potential tannin bleed. There's nothing more frustrating than priming up woodwork as prep for a fresh new paint job and then seeing stains leech through the primer.

Gym- have you had problems on WW that is already coated with a clear varnish of some type? I agree if it is raw or the varnish worn away.
But if sealed it shouldn't be a prob-

Wow! Thanks for the fast responses! So the Zinser oil based is the way to go? And I can use a latex (semi-gloss) top coat?

I also edit my OP to include a caulk recommendation. Thanks!

You can use the 1-2-3 or the oil based with a latex top coat.Like BJ said,the wood is already sealed so bleeding won't be a problem. As for caulking, I like White Lightning it works fine for interiors.Whatever brand of caulk you use make sure it is a paintable caulk.

No sillycone

123 will be fine

If the BM caulk you're talking about is the black tube, that's overkill. Either the blue or green tube at BM is more than enough for interior purposes. I usually use the blue tube.

Not usually........but you always seem to come across wood that WASN'T sealed or was partially sealed, etc. so, to be on the safe side, I use the oil.......but like I said, it's not etched in stone.....

if it bleeds, spot it with BIN. Problem solved..

If the sealing on the wood makes a difference, I may have one or two sills where the sun, moisture, etc., may have worn the seal coat thin, and maybe these are candidates for "spotting", but aside from the obvious (more difficult cleanup), are there other caveats to using oil?

Yes, it's the black tube, but saving a bit (for a still good product) is appealing, since I'll likely need to remove the baseboard in a year or two to replace flooring (I nailed with this in mind...)

I'm a fan of oil but don't like to use it because of smell, cleanup, etc. The latex primers are fine as most everyone on this thread seems to agree. They bond just as well as the oils do to the sealed wood substrate.

Check the paint time on the black tube. the last I heard that was being discontinued, are you getting a good deal on it?