Spraying Latex with HVLP

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I have a Graco 3 stage HVLP. Love it for shellac, lacquer, poly, dye, etc. I bought a bigger tip. I have a 2qt pot that takes pressure from my compressor then a material line out to a gun which has the hvlp air also. It blew the BIN primer well but the Latex\Enamel Semi Gloss was almost to heavy to spray but I got a decent spray after tweaking the flow\air\etc.
I am getting small air bubbles in the paint. Just pin head sized but lots of them they don't pop and end up leaving nibs once dry.
I know this setup is barely strong enough to blow latex but wondering if anyone has any ideas. I did use some flowtrol. Not sure if that was the issue or if I should use more or what.
I am pretty sure I had the gun and lines clear of the alcohol from cleaning the bin and I sprayed one side of 6 cabinet doors and was still getting bubbles although tweaking to lees paint seemed to help a bit.
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SonomaProducts.com wrote:

job for a customer, used Zinnser BIN which I love and then sprayed water based enamel with a HVLP guy. The job came out excellent to my standards and the customers. I found thinning the with water worked well. Also found out the hard way when spraying cabinets, work outside in not the other way around or you will get over spray drying on paint thats drying causing a rough finish and lots of sanding. I'd stay away from latex if you're planning on sanding it. Latex does not sand well. I would not use latex except on walls, not on cabinets or doors.
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On 5/22/2011 9:39 PM, Rich wrote:

...I can't get latex to spray "right" out of my hvlp, either. I ended-up at HD and, too cheap to go for the real deal, bought a Wagner "Paint Crew" airless for a couple of sheets. It works like a champ...little bit of a mess, but the results are pro.
cg
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I would not use latex

Well, at Home Depot I bought what is labled as enamel semi-gloss as I heard it was a little thinner than latex. The guy at HD told me even though it says enamel it is still latex. Then at Lowes I saw their interior semi-gloss enamel say latex elsewhere on the can. I am confused but that is pretty normal.
I can do the cabs I am building by hand but I want to install 11 new pre-hung 6 panel doors and I did two as a trial effort and the nad painting (I used a brush) took way too long. I did it in saw horses, one side at a time, two coats, forever. I was hoping spraying would be fast and nice.
I wonder if some of this Rust Oleum oil based paint would be appropriate? I used it to paint part of my truck and it was thin enough to spray nicely.
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I have sprayed, supervised spraying and problem solved spraying issues for decades. Not always successful but somewhat educated I suggest that latex, when sprayed, should have a serious whack of power behind it and that spells: airless. Flowtrol is your friend, so is a bit of water. Temperature and humidity are huge factors as well. I seldom comment on spraying techniques as there are so many variables that will/can drive you nuts.
Think about it... that stuff is rubbery (In the UK they call it emulsion) so to atomize it requires power. Yes it can be sprayed successfully, I have on many occasions, but you need to stop thinking that shit as being paint. The 'aint' component of the word sums it up.
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The 'aint' component

Nice.
I think I'll look for some oil based "solution" (pun).
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In article <b5547fbb-538c-4741-ba8b-376abf2abcd8@

Not necessarily the only option. See if you can find an M.L. Campbell dealer near you. They have several lacquers (their precatalyzed lacquers are excellent) and if you're in a VOC-restricted locality some good waterborne polyurethanes as well. And a Campbell dealer will generally have other good stuff.
Locally a gallon of Campbell precat costs about the same as Home Despot latex.
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On Sun, 22 May 2011 21:19:00 -0700 (PDT), "SonomaProducts.com"

I had trouble with my HF HVLP conversion gun spraying sg latex enamel. I couldn't buy a larger tip so I thinned with floetrol. It finally shot OK after I warmed the mixture to 100F or so.

How close are you spraying?

It sounds almost as if you're flowing so much liquid that the air is foaming it before it hits the project. It would take a whole lot of air pressure to do that, though, I'd WAG.
Have you called either Graco or Flood about it yet?
You also didn't state how you mixed the floetrol into the paint, but bubbles in paint usually don't transfer whole through a gun. Good atomization should take care of that.
-- Doubt 'til thou canst doubt no more...doubt is thought and thought is life. Systems which end doubt are devices for drugging thought. -- Albert Guerard
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Hmmmm.....
Let me preface by saying this is my own practical experience, and anyone else's may differ.
First, a three stage gun/turbine like a Graco is plenty of machine to spray latex.
Time to woodshed the gun/material setup.
An HVLP is different from a an HVLP CAS gun, which is what most folks have. In theory, these are the same because they both use a lot of air at low volume. Similarites stop there. The "connected to my compressor HVLP gun" is simply a different look at the classic high pressure guns.
Yours (in my mind) is the real HVLP, although I do love my two CAS HVLP guns. The biggest difference is that almost all turbine guns use about 5psi pressure to push the paint in front of the air cap, as opposed to letting gravity or a 100% siphon system feed the gun. With that in mind, poor mixing technique can indeed introduce bubbles in your spray material. Not a problems with the old high pressure guns as they literally did atomize the paint, blowing into tiny droplets. After careful examination of a recently sprayed surface, you will see that turbine HVLP is more of a controlled splatter. Today's finishes are made with the sprayer in mind, and are most forgiving I have ever seen.
With all that in mind, here are my suggestions based on my 12 year love affair with my 4 stage Fuji HVLP, and a brief but productive affair with a pal's 3 stage Turbinaire.
- Toss out the Floetrol. That crap is relic of the past, and is only used by people like me when they have an open can that has started to cure. YOU don't need it. I haven't bought that stuff in 10 - 12 years, and no professional painters under 65 use it. Trust me, today's paint formulations assume a professional will be spraying. Call your coatings rep; he/she will confirm
- Make sure you are using the best quality coating you can afford. Sherwin Williams, Ben Moore, etc., all have a top line that is great. When using my buddy's borrowed Turbinaire three stage, I was able to spray the top line SW semi gloss enamel with no thinning. A lot has to do with particulate size, colorant, and the base material used in material formulation. (For example, SW is zinc oxide based, and Glidden is clay based)
- Try shooting without thinning. Could be a surprise there. If you need to thin, don't overdue it. (Although I have hit SW top line enamel 20% before with no ill effects!)
- Thin good finishes with filtered or distilled water. A gallon costs .99, and it will do almost five gallons of paint. Cheap.
- Turn the gun air OFF. Start a test shooting batch with a 10% thin. Open the coating feed about 3/4 of the way. Slowly open the air pressure till you get about a half feed. Spray a test area on a piece of primed or previously painted wood or sheetrock. This method won't work on bare wood. You should spray out a nice, but thin coat. In another area, open the the pressure valve a bit more, and see if you are still getting a good coat. Wait about 20 minutes and check to see if you have bubbles
- if you do, toss out the paint in the gun and clean it well. This shouldn't be a big deal since you are thinning by volume; you only need a small batch of about 4 oz each to get an accurate batch sample
- Reduce to a new mix of 15%. Repeat. While all guns and shooting conditions aren't the same, most seem to prefer about a 10% to 15% thin, with the pressure at about 1/2 to 3/4 open. I installed a regulator gauge on my gun though, as I couldn't always tell where I was with a face full or respirator. Since you are doing this professionally, I would strongly suggest you do the same for the sake of repeatability
- I have found that a 1.7 tip works best on my buddy's gun for latex, thinned as above dependent on spraying conditions. On my Fuji with a 1.8mm aircap, I spray enamels unthinned unless it is really cool where I am spraying
- Some finishes shoot betterhan others, so I would try a quart of top line products from different manufacturers and see which ones you like and your equipment like. I can't stress enough that unless your gun is actually broken, you have an excellent setup that you just need to practice and test with coatings to make sure you have it all as good as you can get.
- Watch your technique. HVLP guns are actually set to spray patterns similar to our old high pressure guns. If you are newer to spraying, it is important to find your gun's sweet spot. As a general guideline, for this kind of spraying, your aircaps will work best at about 8" from the surface. That isn't much, but it is also one of the reasons you have such efficient material transfer. It is also the reason you use lower pressure; the material doesn't have far to go. It is easy to hit the surface so hard you get bubbles. But think it through; a thinned finished with too much pressure will almost always yield bubbles.
An easy way to tell you have too much pressure is if you spray and find yourself in room full of drift, or you are using the same amount of paint as you do with an airless or high pressure setup. The bubbles are just another indication of too much pressure. It sounds to me like you haven't thinned enough, and your pressure is too high to try to make up for it, slinging the paint on the surface.
Make sure you are <<as close to that 8">> as possible when testing. Even an inch makes a difference one way or another, and the actual sweet spot for my Fuji is about 8 - 9".
Finally, if all else fails, check this out:
http://www.spraytechsys.com/literature/wag_lit/wag_pdf/HVLP_training.pdf
It is one of the most comprehensive, intelligent discussions of practical HVLP use I have ever seen. Good stuff. And while the cap/ orifice tables won't be the same for your fun (such as size 4, or size 3, etc.) since they put the actual orifice size on one of their charts, you can call Graco and they will tell you the equivalent.
Let me know if any of this helps.
Robert
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Well, this gives me some hope. I thought if I could find an oil based enamel it would be thinner but it seems I can only find it in quarts and like rust oleum, which says for metal substrates only.
I'll try buying some better paint than the home depot stuff and see if I can get something to work.
Interesting you say "cap" but Graco sells a needle and an insert. The cap is reused but I assume it is the same, the orifice is in the threaded insert. I got the biggest one they say my gun will push. The next bigger turbine will push the biggest but maybe thinning will help.
Yes, I was at about 8 inches. I think I will try much less material and slow down or do more passes to let it build.
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I would urge you to burn $35 - $40 and buy the best enamel you can get your hands on (really, how much is your paint cost per project?) and then sit down with a tablet and write down temperatures, a guess at humidity, the amount of thinning, and the pressure you shoot at. Before found a gauge I liked, I used to screw my pressure all the way down to closed, and simply count the revolutions I used to open it. I took a file and cut a groove in the knob when it was straight up so I would have a reference. It worked well, but a gauge is better.

With most sprayers, a cap is part of the system. If you buy within certain sizes, one cap will take care of different sized fluid needles. So when you buy from different manufacturers, they think differently; some say a fluid needle/opening will effectively use the same sized air cap, which will blow out the same pattern from the same holes. You adjust your finish from there.
Others think that using a 1mm needle size (the one I use for dyes) requires a different air cap than the one you would use for latex, typically a 1.7 to 1.6 mm fluid size. Different air caps not only handle different amounts of air, but they also shoot different patterns of air into the fluid stream. Since I have a Fuji, I tend to call them air caps as they only sell a few needle sizes and they all come with different caps.

I actually had to resort to a spacer stick to make sure I was spraying at the correct distance. I would spray for a bit, then the gun would move back to about 10" or so, which was great for my high pressure stuff. Or even to 12". I tend to adjust the distance of the gun based on the amount and look of the coating on the surface, which is not the way to shoot HVLP.
I hope you post a follow up.
Robert
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Kelly Moore? This is the only local store I can think of. I am pretty much a big box store guy for anything they carry... except wood.
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Honestly, I have shot their latex out of my airless and rolled out some walls from time to time, but never shot any of their products from an HVLP. They probably have a good product to use, but I couldn't say for sure.
My first shot would be Sherwin Williams. They are the guys that have a product for everything, and their paint goes from pretty good, to excellent. They have many products geared toward the professional, and in my experience have excellent customer support. When the tech guy isn't around here locally, I just call their toll free line and they get me lined out. I don't know how big your city is, but you may be lucky enough to have a trained specialist there and they can get you with the right product.
I have used their "Pro Classic Alkyd Something Something" Latex before in semi gloss and it is great. So is their "Super Paint" line. I have used a couple of other top end products they make in their latex lines, but their names escape me. It is important that you contact a **knowledgeable** sales person (ask for a commercial rep if you can as they have more training) since SW has different products formulated for different areas. Some of the stuff I buy isn't on their website or product list, but I can get it easily. I just call Eddie and I am set, as he looks it up on my account.
If applied properly on a new, dent free, properly primed surface, the Pro Classic stuff will look sprayed if brushed; if sprayed it will look like glass. The upper end lines also carry stern warnings about not thinning their product, and if you have to, not more than 10%. I can tell you I have personally shot their deep color enamels reduced by 20% (!) and had no problems with color degradation.
Benjamin Moore also makes some excellent products, and not but a bit of difference in the upper end products between BM and SW. I have used their Impervo line a lot, and it shoots quite well. They make a lot of different lines, and I have had good luck shooting all of them.
The only reason I go to SW over BM is that SW has a large warehouse here, and if I need a specialty product they will get it pronto. I am EXTREMELY fond of one of their super fast dry/high build enamels. It is impossible to beat for a kitchen paint. But it dries in 15 minutes, so it isn't for the faint of heart. They special order it for me. As with any chain, the local stores have their own flavor, and SW is much more contractor friendly, and they keep better records of what I use. Also, if I can catch their sales, they are even cheaper than HD as they will have products at 30 - 40% off.
Personally, I don't have any problems at all with HD BEHR paint. When rolling and brushing, it works fine. Their enamel is a bit too sticky for my taste when brushing, but still gives an acceptable end product. I use it from time to time as my customers find colors they like on the weekends down there and bring me the paint chips from HD. Their wall paint and enamels shoot very well out of an airless, too. Not much luck with the HVLP.
I don't like Valspar paint at all (Lowe's house brand), so after a couple of unsuccessful goes with it, I don't use for anything and if asked by a client to do so I color match to HD or SW. But, no more Valspar for me.
Robert
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On 5/27/2011 12:06 PM, snipped-for-privacy@aol.com wrote:

What about FreshAire at Lowe's?
I'm getting this product requested frequently these days, did the interior of a new home with it a year or so ago at the customer's request; they loved the results, and the painters didn't seem to have any problems with application.
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In article <58fc9723-ca86-47ce-ade7-

If you're in Sonoma County, California Paint in San Fran has Benjamin Moore, Pratt & Lambert, and M.L. Campbell. There's a Sherwin Williams Commercial distributer (note--this is not the consumer retail store) in Santa Rosa. There should also be an automotive paint store. Between the three you should be able to find a finish for just about any purpose.
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With a business card he can get what he wants at the SW commercial store. At least around here they will let you buy with cash with proof of a business.
But BM makes a lot of great products Sonoma, so you are covered two ways there.
J., I didn't know that MLC made any paints. Can you point me to some info on that? I know they make tinted top coats, almost to obscure, but no paints. I couldn't find them on their website, but like SW, they may not list everything they sell. Our two MLC distributors here are a couple of self important know it alls that in fact no little. If you remember Barry from years ago here, he always loved their finishes and tried to get me to switch. But our local guys killed that deal.
Inquiring minds need to know.
Robert
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In article <065929b0-7174-4c41-b81b-0aa9067e3296

If you mean "paint" in the sense of conventional oil based or latex paints, no. They have opaque pigmented polyurethanes, lacquers, pre- and post- cats, waterborne post-cat urethane-acrylic, and a waterborne precat that they don't say what the chemistry is.
<http://www.mlcampbell.com/products/categories/pigmented_topcoats
These aren't clears with a little bit of tint. They're completely opaque--two good spray coats give complete coverage. They have primers too <http://www.mlcampbell.com/products/categories/primersundercoaters . Magnaclaw primer is white, and one spray coat thoroughly seals MDF, even the edges.
If you want to see an example, I think I've got some scraps around painted with Pratt & Lambert exterior alkyd and with Magnamax in the same color--I could put some pictures up on flickr but basically you can't tell them apart by looking at them.
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UPDATE:
I bought the best stuff Sherwin Williams had, maybe Promark alkyd?. Thinned it 10%, tried material feed pressure from 10lbs to 35lbs, tried changing blower air from about 1/2 to full. Got decent covereage in about the middle of both settings and even more air bubbles in the finish. I'm done. Tired of cleaning the gun.
Gun might be defective or just a little too weak to blow this thicker paint. The cap has two large and two smaller holes for the blower air. It looks like on of the smaller holes is a little munged up so maybe the gun needs a new cap. Still sprays lacquer fine.
I'll spray the BIN primer, sna dout the cabs and hire a painter. I'll also have them paint the 11, 6 panel doors that come primed and the installed pre-primed trim.
Thanks for all the help. If I upgrade to a high-end pressure pot 4 stage steup, maybe I'll try again.
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This is a test. Google news reader is only showing me 17 entries even though it lists 19 and I can't see y last post, although I did see a response to it on my opening page but it is not there when I veiw the thread. A new feature?
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On the left hand column, click on "sort by date". That should do it.
Robert
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