Tip Choices for HVLP Sprayguns

Advice on the ins and outs of matching tips to the gun and the intended use. August 25, 2008

I intend on buying an Accuspray gun in the near future. I had a #10 gun ten years ago and was very satisfied. I have been using cheaper HVLP units recently. I use a pressure pot and occasionally spray from a suction cup. (Although I appreciate its superiorities, I'm not willing to commit at this point to air-assisted airless.)

I noticed that currently 10, 12 and 19 guns are available but I am unable to get coherent explanation as to their differences - even from Accuspray tech support. Why, for example, would I (or anyone else) want a 6:1 pressure reduction ratio (#12 gun) versus a 1:1 (#10 gun)? What I'm interested in is the softest spray and the least amount of over spray that I can get (particularly the latter) and still get a good wet coat with fine atomization.

I'm spraying SB lacquer/CV with a compressor. I have a cheap regulator at the p-pot or the handle of my current gun. Is it worth upgrading to an Accuspray regulator at this location? Needle size/cap size? Any "light" that anyone can shed on the subject would be appreciated.

Forum Responses
(Finishing Forum)
From contributor M:
I have a #10 which I am very satisfied with. I originally bought a #19, which I continually had trouble with. The person who sold me the gun made good on swapping out the 19 for the 10 after I realized that something really must have be wrong with the 19 I bought.

I use a .9 n/n and a 1.2 or 1.3 n/n, with #8 and #10 caps in the model 10 gun, depending on what I am spraying. I use mostly waterbased lacquers from Campbell and General. The 10 gun seems to have the best pattern I have seen, with the least amount of overspray and low volume that I have been able to find in a gun. I have on my gun a regulator that allows me to use my compressor, or remove the the regulator and hook it up to my turbine if I need to.

I believe recently Accuspray was bought out by 3M, so it is no surprise to me about your experience with their support. I notice a big difference in the spray quality of the Accuspray gun and my turbinaire gun over the cheap hvlp guns. You definitely get what you pay for.

From contributor A:
The Accuspray # 10 is a delrin body turbine-driven HVLP gun. With a special regulator, it can also be driven from a compressor. The # 12 is compressor-driven HVLP conversion gun, also made out of delrin. It is very similar to the # 10. The # 19 is an aluminum body, compressor-driven HVLP conversion gun. If you want a turbine-driven HVLP gun, the # 10 is about as good as it gets.

All three guns have been around awhile, and are very good products. I use the aluminum body # 19, and am very satisfied with it. Accuspray offers what, to me, is a bewildering array of air cap (delrin and aluminum) and needle/nozzle choices. The delrin air caps are less expensive, but don't give as fine finish results as do the aluminum air caps. Instead of matched needle/nozzle/air cap sets, Accuspray allows use of a several different air caps with each needle/nozzle size. This can make initial set-up more complicated and confusing. Folks who don't get satisfactory results with an Accuspray gun, don't have it set up properly for the material they're spraying.

Accuspray also offers two choices in needles: all stainless, and delrin-tipped stainless. The delrin tips are replaceable for much less than the cost of a new stainless steel needle - but are also less durable. I like the delrin-tipped needles; some folks hate them. I've purchased spray equipment from Jeff Jewitt at Homestead finishing, and have been very satisfied with his service and advice. He sells several brands of spray equipment.

From the original questioner:
A quick report back on Accuspray choice. It arrived and I have been spraying with it for a couple of weeks. It's been just the ticket as far as results. Iím not crazy about the screw-on cup. I started out strongly opposed, but was won over during the initial course of the operation. Now it's starting to leak and no amount of cleaning seems to be fixing the problem. Drips into a new finish are never welcome. I can always fit a standard cup or go to the pressure pot but it is a $400 unit. All in all, however it's "The Berries".

From contributor M:
Glad to hear it worked out. I too donít really like the screw on cup, but since I donít spray that often, it hasnít been a real problem. If you are looking for a pot, let me know as I bought one last year, and only used it a couple of times. I just donít spray enough to justify a pot.

From the original questioner:
I have a couple of Harbor Freight pots which work fine. The problem though, as always, is the agitation issue. Every fourth time I pick up the gun I forget to shake the pot. The finish goes on ultra flat and I'm back re-spraying in a few minutes. What the world needs now, to paraphrase a quote from another era is a good 5 cent pot agitator.

From contributor P:
I'm not sure what's giving you a leak with your #10 screw on cup. I've had mine two years now with never a drip. Check your rubber gasket for twists or maybe even defects, like cracks or dry/hard spots. You might even try massaging in some plumbers' grease (not plumbers' putty) or even vaseline, but make sure you clean it off with solvent.

I still say you ought to look into the 3M PPS cup replacement. I've used mine twice now and don't think I'll ever go back to aluminum. I can spray upside down and sideways, and cleanup was so much easier. Good luck with whatever you decide.