Need help with my hvlp sprayer.

[keith ouellette]

I bought a used graco 900. It was very clean and only cost $200. The person I bought it from had bought it used and said he never ended up using it and didn't really know how.

Before I paid for it I put some water in it just to see if it would spray and it did. Almost turned the water into a cloud of vapor.

I have a #3 tip which should spray latex. I am spraying a floor paint which is pretty thick though. It just splatters the floor paint so I kept thinning it but even when thinned fairly well I am not getting a fine spray of paint. Just spurts.

Is this a problem with the gun like the gun is worn out or is the turbine bad? The gun is the original gun so its pretty old.

[Jamie Buxton]

The floor paint may be just too thick for that sprayer. Try shooting somethingthinner -- more the consistency of waterborne varnish. If you get good results with that, you know the system is basically okay.

[David Thompson 27577]

Although there are numerous possibilities, I'm gonna bet that the tip is worn out, and that the pump needs rebuilt. Really high-quality spray equipment (like the entire Graco line) doesn't come cheap, unless there;s something wrong.

[Jack Clark]

Keith,

Based on my little bit of experience, I would suggest you Google viscosity cup and do some reading. Then consider purchasing an inexpensive Ford #4 viscosity cup.

For example, with my cheapo Ford #4, plain tap water takes about 14 seconds to drain from the cup. Behr Interior wall paint takes 4 to 5 minutes. In my HVLP spraying adventures, I've found that thinning thicker materials (e.g., stuff that takes over 60 seconds to drain) to around 30 to 40 seconds makes for much easier spraying. That wall paint right out of the can really won't go through an HVLP gun in any sort of nice manner...

Except for shellac, which is water-thin, I pretty much stick with waterborne materials. There are many waterbased products on the market now that spray wonderfully right out of the can, that is, no thinning necessary.

I'm assuming your floor paint is waterbased. When I do need to thin a heavier waterborne, I've found that Benjamin Moore Extender (51800) works much better than water or Flotrol or water plus Flotrol, which is often recommended. The Benjamin Moore product is relatively easy to obtain at your local Benj. Moore dealer. It doesn't seem to affect the sheen.

Jeff Jewitt's book and DVD Spray Finishing Made Simple is excellent. I wish it had been available 5 years ago.

Hope this helps.

[keith ouellette]

Well I just did a test with my cheap HF hvlp gun with the 1.8 tip (I think thats 1.8 mm but not sure if thats what it means) and the same THINNED paint that is spurting from the graco 900 will spray out of the harbor freight gun.

The Compressor (i think its a turbine) seems to be moving a lot of air but I don't know at what pressure. Can it still have a high volume of air if the compressor is bad enoungh that it wont have pressure.

[Jack Clark]

Sounds like floor paint is plenty thin enough.

Does the cup on the Graco unit have some kind of a breathing vent that may be plugged?

I reread my earlier post. Kinda sounds like a mother-in-law lecture. For this I apologize.

[Chris Fournier]

Good points made already. Viscosity is everything! Also if you are spraying a floor it may well be that by tipping the gun down, you have gummed up the pressure passage to the cup. The one way valves will also get stuck and you can blow on them both ways to test for this.

If I had to spray this floor paint I'd use my pressure pot as it makes a world of difference and the gun attitude doesn't matter either.

Blobs mean that there's not enough air to atomize the paint in the viscosity or quantity that it's being delivered. Open up the air valve, close up the fluid needle and see what happens.

I would buy a larger needle and tip setup for the latex paint as an off the cuff guess.

[keith ouellette]

No problems here jack. I appreciate the info you gave me. I'm doing a book case so the gun is up right. I tried thinning the paint way down and that didn't work. I had to thin it much less to spray with the HF hvlp conversion gun I have( That things actually works quite well now that I have it figured out).

How would I test the turbine to see if its putting out the right amount of pressure and what is the right amount of pressure? It sure seems like its putting out a lot of air though.

[Mike Ruggeri]

I don't know your spray unit, but you might just want to try spraying water. You should be able to easily adjust the gun to spray that on some cardboard. That way you can get a better feel if it is the paint or the sprayer. I assume you checked the tip and the rest of the gun to make sure all is clean with no obstructions?

Mike

[Jack Clark]

How would I test the turbine to see if its putting out the right amount of pressure and what is the right amount of pressure? It sure seems like its putting out a lot of air though.

Sounds like it's time to phone Graco customer service.

[keith ouellette]

I don't know your spray unit, but you might just want to try spraying water. You should be able to easily adjust the gun to spray that on some cardboard. That way you can get a better feel if it is the paint or the sprayer. I assume you checked the tip and the rest of the gun to make sure all is clean with no obstructions?

Mike

Sounds like it's time to phone Graco customer service.

Mike:
Water was the fisrt thing I sprayed wen I tested the gun before I bought it. Sprays water like a champ.
Jack:
I think your right. I never thought of calling them. thanks. I'll try in a few days and post my results. Right now I have the HF hvlp conversion gun dialed in pretty well. I originally thought the graco would do a better job but the HF gun is actually performing very well. I still want the graco fixed.

[Jeff Monson]

Keith I own a Graco HVLP, although I'm not familiar with the 900 series. I'd doubt the turbine is worn out, mine has a good steady gush of air, but no real pressure to speak of. If they still use the same tips, that sounds too small to work for a thick paint. I'd try something along the lines of a laquer or varnish to see how it sprays that, if it does a nice job then you know the equipment is ok. When I bought mine, the Sherwin Williams guy (who really knows his Graco) told me not to expect great results from my HVLP if I were going to try any latex paints. Also my clear vent tube from the cup to the gun has a 1 way valve in it, if it gets plugged I get very bad performance.

[Henry Ambrose]

There's a little valve in the top to the can that might be clogged or stuck shut. Its a duck-bill affair that can be cleared by pinching it open gently or it may need to be replaced. Calling Graco is a good idea though. There are also 2 adjustments on the gun for pressure and spray pattern - have you messed with those? Do you have a manual? Good luck and let us know how it turns out.

[Howard Acheson]

First thing I would do is contact the manufacturer and get a copy of their instruction manual(s). Then I would order a copy of Charron's Spray Finishing from Amazon. Between the two it will tell you how to set up your equipment, how to select the proper tip for the material, how to use the adjustments on the gun and air source and, finally, how to determine the spraying process to get the best finish.

Spraying latex paint is not the best use of a HVLP set up. Water is not the thinner for most latex paints.

I would also suggest you disassemble the gun and thorough clean it out. Get a gun cleaning solvent. You can get the solvent at most auto body repair suppliers. You can generally get a re-building kit from the manufacturer

[Steve Jenkins]

My brother just went thru a lot trying to spray latex with a turbine hvlp. He was thinning with flotrol to the proper zahn cup and was having no luck. splattery finish that would not lay down. He spoke with someone and they told him to use water instead of the flotrol and it worked perfectly. Don't have any idea why.