I'd asked here about spraying latex paint with a 4-staje Fuji HVLP. While the paint seemed to go on OK, the luster wasn't what I expected at all. Even gloss paints dried flat.
I was following the instructions that were provided with my sprayer, which said to thin with water and add Floetrol to get 20-30 seconds through the viscosity cup. The Behr "Premium" interior and exterior paints I was using required A LOT of water to get that time through the cup. This was, it turns out, altering the chemistry of the paint in a not very desireable way.
Robert suggested not using the Floetrol, and thinning MUCH less. He suggested starting at 10%. I did thin 10% at first, and it didn't seem to change the viscosity of the paint noticeably. It sprayed just fine. I figured I'd try not thinning at all, and I found that my sprayer (with the #4 needle and cap) worked fine with paint straight form the can. I was amazed, seeing that this paint would take tens of minutes to get through the viscosity cup unthinned.
Another error I'd been making was in the thickness and the timing of the application. I was applying a very light coat, and waiting only 15-20 minutes between coats (as soon as the paint seemed dry to the touch, I was recoating). Robert pointed out that, properly applied, latex will take MUCH longer to cure to the point that it can be recoated. So I fooled around a little with speed of gun movement and distance to the piece, and found that I could apply a pretty wet coat without having any runs. I let this dry for a couple of hours before a recoat. The result was, naturally, many fewer passes to build a sufficient covering. And the results are as they should be; gloss paint is actually glossy when its dry! (And, it is amazing to see the paint continue to level itself out after it feels dry to the touch - a fingerprint put into the paint 20 minutes after application was gone within another 30 minutes or so.)
I like working with water-based coatings primarily because I don't have a proper place to work with laquers, and because cleanup is so easy. Painting a woodworking project is something I do very rarely at the moment, so far confined to a couple of plant stands for use outdoors, a small closet shelving system for SWMBO and a couple of picture frames made with poplar. But having some success with gloss latex now (and it seems so easy, thanks to Robert), I'm a bit more emboldened. SWMBO and I like the mid-century modern and some contemporary furniture styles, and lots of the pieces we've seen and like are painted. So perhaps I'll try making a few small pieces in that style now.
And no, I won't be painting any cherry .....
artg at eclipse dot net
artg at eclipse dot net
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