Spraying Waterborne Paint on a Budget
Finishers discuss the challenge of applying waterborne paints using inexpensive equipment, without having to over-thin. September 18, 2012
Question
Has anyone sprayed BM Advance? It is a waterborne alkyd and I need to spray it out of a hvlp. BM indicates to only thin with 8 oz. of water per gallon but I used 3 oz. per 16 oz. with a 2.5 tip and could just get it to atomize at 30 psi, which is more than an hvlp allows. I know it’s indicated not to thin solvent products because of the voc. but this is a waterborne alkyd. I’m just wondering if they indicate only 8 oz. per gallon because it is an alkyd. I sprayed a test sample and it lays out nice.
Forum Responses
(Finishing Forum)
From contributor J:
I have had good luck spraying the BM Advance using a Titan Airless pump and a Kremlin MX gun with some adaption. I use the air assist, set at 30, from the Kremlin pump. The Titan is set about 500 -600 lbs. (at about 10 o clock on the dial.) I do not thin the paint and I spray two passes.
From the original questioner:
I only have an hvlp setup so I need to thin it. I'm just wondering if it matters how much I thin it as 8 oz. per gallon is nothing. Like I said I am barley able to get it to atomize at 3 oz .of water per 16 oz. of paint.
From contributor J:
I wouldn't add any more water to the paint beyond what the manufacturer recommends. The finish could fail, and then you'd have a bigger problem. It would be best to go to your nearest paint store and rent an airless sprayer for a day to paint the job.
From the original questioner:
I wonder if it would spray out of a Wagner power painter? I only need to spray about a quart and a half. I never used one but I think they spray latex paint.
From contributor P:
You could also try using a bigger tip in your gun.
From the original questioner:
2.5 is the biggest tip they make for this gun. This is not something I would usually spray but my customer wanted it and I thought it would be a good opportunity to experiment. My local rental company wants $75 a day to rent an airless.
From contributor H:
Before you spray your product, drop it into a bucket of hot water. I will repeat the process a few times until I get the material to about 95 degrees. Most times I will not have to mess with thinning and it flows out of an airless very well. You can get the viscosity down by about one-third.
From contributor J:
I think the Wagner might work. Good luck if you haven't already tried it.
From the original questioner:
Thanks Contributor J - I am going to rent the airless and do it this weekend.
From contributor R:
Ever seen a rental airless? Make sure to plan on a few hours cleaning it before you use it. My only experience was renting one to paint my house. I was finally getting a good fan pattern about the time I was finished. They told me they had never seen it as clean as when I returned it. I wouldn’t consider a Wagner, and certainly not a low cost price. They are not about atomization - they are about throwing paint on a deck or patio furniture.
From contributor P:
You could buy a waterbased product that is designed for spraying, like MLC Agualente, General Finishes, Fuhr, etc. Most, if not all, can be tinted to match any BM color. I do it all the time.
From the original questioner:
Contributor R - I will take your advice about renting the airless. My paint store guy told me the same thing about people not cleaning them.
I am going to switch to oil Impervo, then I can thin it with naptha to get it to spray out of an hvlp. The reason I am using paint and not GF pigmented poly is that I need to brush and roll some other things on this job with the same product.
From contributor H:
I use GF with the accelerator to spray and not accelerated to brush on the same job. It works well when there is no way to spray on site. Oil Impervo also sprays well with a naphtha cut. The trick I have learned is to tint your primer as close as you can, prep everything, spray two wet on wet coats, then walk away. It sprays well out of the Harbor Freight gravity gun - why ruin your expensive gun. It smells funky, but flows on almost like the oil's of old!
From the original questioner:
I purchased the Harbor Freight gun and it has a 1.4 tip. Is that big enough to spray the oil Impervo without having to thin it too much?
From contributor H:
I use that tip for Oil and for Isocyanate urethane. If you use the 1" dribble method to thin your material you cannot go wrong!
From the original questioner:
What is the 1" dribble method?
From contributor H:
Thin your material so when you pull the trigger (with the air not connected) you get a 1" stream of material out of the fluid tip. That will give you a quick field test of the viscosity of the materiel. Too thin and the materiel will not atomize, too thick and it will not atomize.
From the original questioner:
The Harbor Freight gun sprayed the Impervo like a dream, although it looks orange peeled off the gun so I hope that it lays out nice.
