I’ve been spraying my first piece over the past few days – a bookcase. I’ve got 4 coats on so far of a Sherwin Williams semi-gloss paint. I’m thinning it with water between two parts to one and three to one.
I can’t seem to get a shine to the paint. I know it’s just semi-gloss, but all I’m getting is a flat, not-smooth finish.
Any suggestions would be welcomed? I’m guessing I need to give more information too but I’m not sure what else to give.
Replies
How're you spraying? HVLP? Does your setup have the cajones to spray thick bodied material? Is the finish slightly rough? A lot of times a "flat" finish is actually caused by either the paint not having time to flow out before drying, or overspray settling on the finish. Don't spray when it's hot, or in direct sunlight, either of which will cause the paint to dry too fast.
PaulB
http://www.huskytools.com/Product.aspx?pid=d13e708f-cc90-4020-b63c-61ca3a45ba24&cid=801431
Using the big box Porter Cable pancake compressor that comes with the two nail guns.
The finish is a little rough. Spraying in the garage, out of the sun and the temp is around 75 to 85 degrees.
I'm going to try with the garage door open to expell the overspray and a thicker mix of paint.
Make sense?“The richest genius, like the most fertile soil, when uncultivated, shoots up into the rankest weeds..” – Hume
Make sure you're using the correct tip set for latex. Too large an orifice will give you droplets the air jets can't shred. A lot of times guys won't have enough pressure to spray latex and they try to compensate with a larger tip set to reduce the pressure required to pump it.
You should be able to get a good wet coat without runs and sags with the gun about 8" (typically, your gun may vary) from the work. A "dry" coat will not flow out as evenly. Keep the gun parallel to the work and move in long strokes.
BTW, I'm not familiar with that specific paint. Does it say that it's usable with HVLP? Many aren't... and won't spray worth a cr*p.
HTHPaulB
BTW, I'm not familiar with that specific paint.
That's because I made it up. I thought I was using Sherwin Williams (got it from the customer).
But it's actually Benjamin Moore Pearl finish interior latex. What is a pearl finish? Semi-gloss? Gloss? Eggshell? “The richest genius, like the most fertile soil, when uncultivated, shoots up into the rankest weeds..” – Hume
My guess is that it's an eggshell... talking to a paint rep recently I was surprised to find out that there's really no rhyme or reason, nor consensus between manufacturers.
PaulB
BTW, I just reread your earlier post... my strong guess is that you don't really have enough power to spray latex well. I'd look at the gun's specs to se what the CFM and pressure requirements are and compare them to your compressor, but my guess is that the compressor isn't going to have enough to drive that gun. Hope I'm wrong...
Edited 5/27/2007 2:52 pm ET by PaulBinCT
It's tough to spray latex from a HVLP without a pressure pot. I usually spray SW ProClassic thinned 20% with a tip pressure of 35lb, and 70 at the compressor. Sounds like you may not have enough pressure, or you're too thinned. Try making horizontal passes, then going verticle, kind like a cross-hatch. You can cut down on the material feed a little, and still get good coverage and film thickness that way. Was the case primed? Cause sometimes WB will raise the grain. Sand it down and try again.
Not to be negative, or anything, but...
If that pancake compressor is the one I think it is (C2001-WK, 6 gal.), it can put out 2.6 SCFM (@90 psi). Per the manual on your spray gun it needs 8.9 SCFM. First problem.
I can't tell about your gun - looks from the manual like it's designed to spray paint, but doesn't which kind. Latex & oil are way different animals to spray. Since it doesn't appear to have interchangable nozzels/tips you don't have the flexibility to swap them out to get the best orifice for the material (assuming it's too small as-is). Second problem.
As others have pointed out - way to thinned. Third problem.
You might want to think about renting a spray rig designed for the job.
it's a small project - to small to rent a rig.
I'm actually going through the mental process of justifying the purchase of something much better.
In about 3-4 weeks, I'm taking a finishing class at the March Adams woodworking school. I'm looking forward to coming home from this class with the knowledge and know-how to buy and use a real rig.
thanks everyone for the input.
That sounds cool - a real class. I've got the books but there's nothing like hands-on with immediate feedback.
FYI, when you're ready to buy Jeff Jewett is a great source - http://www.homesteadfinishing.com
FYI, when you're ready to buy Jeff Jewett is a great source - http://www.homesteadfinishing.com
This post doesn't show it, but I have read quite a bit from his site. He knows everything. Most that I've read has been about shellac finishing.
I can't wait for the class, haven't been to this school before but it sounds perfect.
Monday thru Friday with the teacher for 8 hrs a day. We can stay in the classroom for several hours after class is done too. I plan to dive in head first and take in as much as I can.
What a great vacation! Color me green ;-)
We'll expect a full report when you return!
Spraying latex with an HVLP is tough at best. I have an HVLP that we use strictly for very thin materials,-polyurethanes and lacquers. I have tried the HVLP for paints-way to difficult to achieve consistent result. For paint we use airless sprayers-great finish everytime and frankly not that much more overspray and much more forgiving than the HVLP.
Bruce
Buy a $100 pressure pot, and put about 20 lb in, and you can get a much better finish than with airless. Sprays the thin bodied stuff better too.
I wish it was so. I have a nice gun and two pots from Jeff Jewitt's company Homestead Finish. Great luck with the thin stuff, inconsistent with the paint.
What kind of gun. I've got a couple Asturo 9010's and use a 2.2MM tip for the SW material, and it comes out smooth as a baby's but*. I spray two coats of primer, sand the first, leave the second, and shoot two coats of finish.
Might want to call Jeff and see what's up? He's always been a big help to me.
Thats basically what I call a conversion gun and its not really meant for latex. I also think thinning it with water is going to cause you all kinds of grief. If you must thin it, using floetrol is far better than water. Water can make it dry uneven, color uneven, and the sheen uneven.
Anyway. An airless is a better bet. And you could do it in 2 coats with plenty of coverage. Not tryin to jump you, but what you're attempting strikes me a little like driving nails with a set of pliers. You'll get there . . . but theres better ways.
Real trucks dont have sparkplugs
IMHO, Floetrol is good for brushing, but you can throw it out for spraying. Water does fine for me for the last 8 years...
"I'm thinning it with water between two parts to one and three to one."
Thinning with water, three to one, are you serious? Even if you mean the other way around, one part water to two or three parts paint, you're stressing that system too much. Latex paints need high pH values (around 8 to 9) to stay in suspension and to form a good film. By diluting with so much water you are lowering the pH into the mid-7's and harming the final film quality. That may also explain why the gloss is so poor.
If you must reduce latex paint drastically, at least add 5% or so of ammonia to raise the pH so as to give the stuff a fighting a chance.
Thanks Bruce.
I have to admit that I misread/misremembered my directions. I will try one more time with 10% water and floetrol.
I'd use flotrol instead of the water, but either way that's thicker paint than your gun was designed for. You could spray some oil based paint much easier. If spraying directly on bare wood be sure to use a sealer or primer. Lacquer is so easy to spray that it would be a great place to start.
Beer was created so carpenters wouldn't rule the world.