Basic HVLP reco for friend

[Joe Jensen]

I have a friend at work who needs to spray 20 interior doors with tinted poly. She is pretty handy so I think she should use an HVLP setup. I'd definitely like to keep it under $200. What do you recommend. Keep in mind that this will likely only be used for the door project, and I think we need to keep the poly prep as simple as possible. She is very set on oil based poly as she has small kids and believes it much more durable. She will be spraying this either outdoors (likely) or in the garage. she is testing Minwax Polyshade tonight with a foam brush.

And...no, I'm not going to volunteer to spray for her, I HATE :mad: finishing...joe

[Steve Schoene]

Oil based poly is not a good candidate to be sprayed. It dries slowly enough that the overspray leaves everything in the area a sticky mess. However, solvent based spray finishes, some of which such as conversion varnish, would be as durable as the poly require more specialized spray equipment. The weaknesses of good waterborne finishes aren't in scratch and wear resistence, it falls short of oil based varnish in terms of chemical and heat resistance, things that aren't likely to be a problem with doors.

Some more info might be helpful. Knowing of what material the doors are would be useful? Why tinted poly? A toned finish requires better spray technique to look good. Unless there is a specific reason, staining first and finishing with clear top coats turns out to quite a bit easier, despite having a separate stain step, and usually ends up looking better.

[Joe Jensen]

Thanks Steve.
The doors are knotty alder and were previously finished (5 yrs ago) with Minwax Poly by the same friend. They had a substantial addition to the home and the new doors are also knotty alder, but the new doors were finished with a very dark walnut stain and then poly. These were finished by the builder.

The friend was going to strip the doors and then stain and finish the way the new doors were finished. I suggested that she might be able to just scuff the surface and overlay with a tinted top coat. Obviously this is not the ideal approach, but the friend spent all available funds on the addition.

I assume water based poly can be tinted, with what product? Can we put water based over 5 year old poly with just scuffing the surface?

I have sprayed a fair amount of poly here in AZ. I thin with Lacquer thinner and the drying time isn't too bad with thin coats. A thin sprayed coat will be dry to a light touch in about 10-15 min (no dust issues). The only time I run into trouble is when I try to lay down 3-4 coats, a coat every 15 min. If I don't let it dry an hour between light coats, the lacquer thinner in the subsegent coats will loosen earlier ones and vertical surfaces will sag...joe

[Steve Schoene]

I assume water based poly can be tinted, with what product? Can we put water based over 5 year old poly with just scuffing the surface?

[/QUOTE]

Trans Tint will work for water based poly, and over well cured finish there shouldn't be a compatibility problem. I would do a thorough cleaning, with TSP and with Naptha before scuffing. The waterborne will adhere to scuffed varnish, but may not to old cooking grease. The TSP gets the water soluable dirt and the Naptha the oily stuff. Be sure to use lots of rags so you are removing the solvent, not just using it to smear grease around. Otherwise it should work fine. Target USL waterborne is designed for spraying and has a very good reputation. Homestead finishing is a source for it and for the TransTint.

[Joe Jensen]

Steve, I just recently bought my first HVLP setup (conversion) and some Target USL. I have yet to try it. How quick will the Target USL dry to the touch (dust free stage)?

thanks...joe

[Jim Becker]

USL is dry to the touch in about 10 minutes if you aren't gobbing it on...

[Tim Sproul]

I'd wait a little longer than 10 minutes before handling. Give it 30 minutes before going for the second coat. You don't want to leave your fingerprints as permanent additions to the topcoat.

Environmental conditions will dictate drying time....cool and humid and less air movement equals longer dry time compared to warm and dry and adequate air movement.

[Jim Becker]

I'd wait a little longer than 10 minutes before handling. Give it 30 minutes before going for the second coat. You don't want to leave your fingerprints as permanent additions to the topcoat.

Agreed...I was answering more toward the "dust sticking" side of thing. 30 minutes prior to any handling is absolutely sound advise.

[Tim Sproul]

Jim,

I should have stuck a smiley or two in my post. It might have come off as rather crass. Not my intention if it did.

Tim

[Jim Becker]

Tim, NP...it actually did need clarification for any newbies reading this thread. "Dry to touch" isn't "dry" or "ready to handle". It's just "no longer sticky" or no longer a nice "molasses bath for bugs"...
. :D