HVLP HELP

[MIKE Smith]

I BOUGHT A NEW HVLP SPRAY GUN FROM TSC AND IM NOT HAPPY WITH IT I CANT ADJUST THE SPRAY ANY WIDER THAN A 4" PATH IM SPRAYING MAGNLAC LAQUAR MY OLD NONE HVLP GUN WORKS GREAT BUT TO MUCH OVER SPRAY I HAVE THE PRESURE SET AT 40LB THE MAX FOR THE GUN I SEEN PICTURES OF OTHER HVLP GUNS WITH A MUCH LARGER AIR LINE FEEDING THE GUN WITH A REGULATOR AT THE GUN IS THIS MY PROBLEM CAN ANYONE HELP THE GUN IS FROM CAMBELL HAUSFIELD

[Ken (Ottawa Valley)]

From reading between the lines it sounds like you're using a compressor for an air supply. If you bought a true HVLP gun you need a turbine which supplies much higher volumes of air at lower pressures. There are hybrid guns that run off compressors but I'm afraid I don't know anything about them.

[Wally]

I too bought a HVLP gun that ran off a compressor and was never really satisfied with it. It did reduce overspray when operated at around 30 psi
but did not have any more coverage that my normal gun. Then I bought a Graco Turbine c/w gun and 1" hose that will produce a 10" fan if needed. It is great for lacquer and easy to use.

Wally/Calgary

[MIKE Smith]

maybe if i used a 3/4 in hose off my compressor and a regulator on the gun leave the comp. reg.at 100lb 30 at the gun ?????? what i have noticed is every time i pull the trigger my regulator jumps from 40 to 20lb no air volume in the small line???what do you think??

[Steve in Kemptville, ON]

Q about HVLP..
I've been researching a bit on which HVLP to buy and as with most things there's a bunch of choices.
The CH website has 2 and 3 stage turbine systems and they state in the application paragraph that the 3-stage might be too much for furniture (in a hobby environment remember). They are recommending a 2-stage unit from what I can gather for all but BIG spray jobs like maybe a house or something.

They make a HV2000 which is and HV3000 gun with a HV1500, 2-stage turbine. Do these loomk like decent units or what would you recommend for the same price range )around $400-$500.

I will be spraying a variety of finishes from Shellac to Poly and maybe aniline dye stains.

Tks.
Steve

Campbell Hausfeld (http://www.chpower.com/catalog/catalog_list.asp?categoryname=Paint%20Sprayers&categoryid=152&subcategoryid=1901)

[Steve in Kemptville, ON]

Your regulator is undersized. Your gun is demandin more CFM than your reg can deliver with a 40psi outlet pressure. When you pull the trigger the regulator can't keep up the 40psi and only achieves the required flow at 20psi. Basically it's a function of pressure drop across the reg. Say your gun needs 100cfm @ 40psi and your compressor is at 120psi. That means your reg must be able to flow 100cfm with a pressure differential of no more than 80psi. Yours would need 100psi to flow the needed 100cfm and thus you only get 20psi output on the gauge.

Remember that you should size the reg based on your MIMUMUM pressure (cut-in). If your comp. cuts in at 90 then you should size the reg to flow the needed CFM at the difference between 90 and 40 or 100CFM @ 50psi pressure drop.

Bigger is better in this case. Even if you have your reg at the gun it still needs to be sized properly.

[Bob Wolfe (Weyburn,Sk.)]

Mike:
With my regular spray gun, I never ran it an more than 30 psi on the regulator. If you nee more presseur to spray, I think you need to thin the product. I always thinned my lacquer 10%.
I have bought a new Devillbis hvlp gun, run off a compressor. The minimum inlet presseur for this gun is 20 psi and the max is 25. It came with a regulator that goes at the gun, which I have set to 20 psi with the trigger open. Works great, but more overspray then anticipated. I have sprayed paint and urethane so far.
BW