First, I want to send a HUGE THANK YOU to Robert (a.k.a.
"nailshooter41") for selflessly sharing his knowledge on this subject.
Robert definitely knows his stuff, and he willingly takes the time to
share his knowledge.
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
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