I have a HVLP spray gun P,C. gravity feed.
What is the recommended ratio for thinining latex paint to be able to spray the material. The product is Dunn Edwards semi gloss.
I have a HVLP spray gun P,C. gravity feed.
What is the recommended ratio for thinining latex paint to be able to spray the material. The product is Dunn Edwards semi gloss.
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Replies
I usually use 4 or 5 to one.
But it depends heavily on the latex paint. In many cases, the paint producers seem to equate thickness with quality -- so they add thickeners.
So, if the paint is the consistency of paint, then I use 4 or 5 to one. And if its more like pudding, I use a different paint.
And you should consider using something other than water as the thinning agent. Floetrol is great, and it retards the drying time. This can help give time for the paint to even out odd textures and marks.
Denatured alcohol also works great (so long as you're outside, or have adequate ventilation), and it speeds up the drying time. Flashover will happen in a few minutes, and dry to the touch in way less than thirty.
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"In many cases, the paint producers seem to equate thickness with quality -- so they add thickeners."All latex paints contain thixotropic agents (thickeners) to prevent them from sagging while the water is slowly evaporating out. Higher gloss products tend to be less viscous in order to enable some flow for smoother final film. I assume you mean 4 or 5 parts paint to one of diluent. Your suggestion of ethanol is good, because much of it will evaporate in the air after atomization of the paint but before reaching the substrate, resulting in smaller droplets with less chance of sagging. Even so, you are recommending a 20%-25% reduction, which may reduce the pH value below what the resin can tolerate without degrading film formation (usually about 8). Any time you reduce latex or acrylic emulsion paints more than 10%, it is advisable to add 4 oz of household ammonia per pint of alcohol to keep pH at 8 or above.
BruceT
Yeah, what you said.
And a Vis. cup helps.Spheramid Enterprises Architectural Woodworks
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"And a Vis. cup helps."Absolutely. Especially if you want to get consistent results each time you spray.BruceT
What's your opinion of Floetrol?
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Floetrol helps paint to flow, thus reducing orange peel or brush marks. It will not help paint to atomize finer through any kind of spray gun.BruceT
I'm quite sure there are ten thousand chemists in the latex paint industry, all of whom can make statements like the one you made -- which supported some of what I said, and added caution to some other stuff I said.But there are about a million of us who use the stuff. And probably a tenth of us grew up using the real paint -- oil-based.And what we have forgotten about oil paint is more than we'll ever need to know about latex.Because with oil paint, you needed to know how to paint. It was a skill, that took time to learn.On the other hand, with latex, mostly what you need to do is get it out of the bucket, and onto the wall. In whatever fashion you can.
I won't be laughing at the lies when I'm gone,
And I can't question how or when or why when I'm gone;
I can't live proud enough to die when I'm gone,
So I guess I'll have to do it while I'm here. (Phil Ochs)
I agree with you about the old alkyd paints. I miss those wonderful oil based products that, when applied properly, could flow to a glassy smooth finish. I think it takes more skill now just to get a decent looking semi-gloss finish using today's latex junk and the finished film will still be inferior in every way. Mostly, I think, people have come to accept orange peel because they don't know any better.BruceT
You may need a larger tip, needle and spray cap.
A lot of guns are set up for lacquers, or water-base finishes. You're not going to get a good finish if you can't spray it at the right rate, and just thinning the paint doesn't always work.
I think the recommended ratio is the lowest one that will allow you to get good atomization and if you can't without a lot of thinning, either get a different tip/air cap set or use a different set up. I have a large Graco and routinely spray it unthinned...
PaulB
http://www.makeabettertomorrow.com
http://www.finecontracting.com
I want to thank everyone who has responded so far. I do have the largest tip for the hvlp gun and will try to thin the paint with a bit of alcohol and a touch of ammonia. I am going to be spraying louver doors so its the only way in my eyes other than breaking out the Graco airless, but I have never used it on trying to spray things other than stucco and sheet rock. any suggestions?
Tony
If you can't get the latex to atomize properly, I'd try the airless... lots more mess of course but beats spitting blobs of unatomized paint. PaulB
http://www.makeabettertomorrow.com
http://www.finecontracting.com
Do you have to use latex on those louvers? Why not head over to Frazee or Vista and get some lacquer that you can spray with a cup gun and have control over fan and paint volume?Even their so-called water borne lacquers spray far better than latex.BruceT
Edited 10/5/2009 8:34 pm by brucet9
Please understand that I hate to paint and am not a painter. But, I have pretty much given up on the idea that a small paint project requires a gravity gun. I have a gravity gun and 2 airless sprayers. I suggest going to a real paint store and buying a 408 or 410 tip for your airless and get to spraying. Sure you'll spend time cleaning up, but you will definitely be satisfied with the final finish.
Save your HVLP gun for lacquers and stains.
Best of luck,
Frank
Tony all these responses here are good valuable ones. Theres also another place that is a great place to go
http://www.homesteadfinishingproducts.com/phpBB2/index.php
I'll throw in with brucet9 , i use a ford cup at 21 seconds the diameter on the tip i used a 1.5 tip from apollo in a bleeder type cup. Also a 1.5 tip also 24 seconds on a gravity fed ,got better results from the compressor /gravity fed cup. I found besides the mixology which is 50% of the process, tip size as shep - said correctly corresponding the tip size to the time of year,paint. it really is practice, practice. the higher the quality the paint the better the results they seem to take all additives better.
Hi all just FYI the recommendations all helped out very much to paint the louver doors. I finally chose to use the denatured Alcohol 20 % cut and it worked out great. I did not add any ammonia and I just did not think it was needed. I did strain all the paint and found that it is always good practice to do that with any finish as I was taught years ago.
Thanks again for all the help.
Tony
TonyCz,
Why do I feel like I'm responding to Inspector Gadget? I sense that using the sprayer is of higher importance than the actual painting project, no matter the practicality of it. Do you have to justify its expense to someone else by actually using it? Interior room with furniture moved from the walls but still in there, plus existing finished trim -- no spray. Given six roller refills per room in my house when painting (I don't clean them, just toss) and those little pads for cutting in, versus the cost of a srayer, I could probably put down the cost of a HD LCD monitor, with LED and 240 Hz refresh instead.
I take it you have never painted 10 shutter doors 32" x 80" before. If you had, you would surly understand the complex nature of painting this type of door. It was never said I was painting a room.
I suggest you start reading this thread from the start for better insight into this task.
Cheers.
regardless whether it was shutters, louvered doors, or LCD TVs you were painting, I learnt a lot from this thread. Thanks for starting it
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Do you have any pics to post or anymore bits of information on what to do and not do?