Differences in Air Compressor Sprayers

[Eric Wheeler]

Just wondering if there is anyone here that is familiar with painting cars and houses/wood, etc. I've always had this question in the back of my head. Is there a difference in the sprayers to paint a car vs wood, drywall, etc. I'm talking sprayers that plug into a regular air compressor only. I know all the piston pump sprayers and whatnot that have their own compressor unit included, are totally different.

[Scott T Smith]

Eric, I am not an expert, but from my limited knowledge automotive paint is a thinner viscosity than house paint; therefore sprayers for house type paint have larger nozzles.

If you thin down house paint to work in an automotive sprayer (as I did today), you risk having more runs due to the extra thinner that was added.

[Eric Wheeler]

Eric, I am not an expert, but from my limited knowledge automotive paint is a thinner viscosity than house paint; therefore sprayers for house type paint have larger nozzles.

If you thin down house paint to work in an automotive sprayer (as I did today), you risk having more runs due to the extra thinner that was added.

So maybe sprayers for automotive have smaller orifices?? Just a guess on my part from the info you provided...if I am correct on this, is there anything else that would be different...if one were to just put in the bigger orifice for the thicker paint, would the gun function the same?

[Josiah Bartlett]

Its complicated. There are new automotive finishes that are thicker than traditional auto paint. Water based base coats are available. A gun intended for this or for high build primer may work, depending on how much you are allowed to thin your paint. Some paints may dry in the air if you try to spray them with an air type sprayer.

For cabinets, you can actually get really nice results with automotive or industrial enamels.

[Mike Reinholtz]

Not sure if this helps, but here is my experience so far:

I use a Capspray 4 stage HVLP sprayer for sealers as well as acrylic enamel automotive paint. The machine is also listed for Latex paint, but requires using a different orifice which I haven't tried yet. For exterior paint I use an airless Graco machine, it sprays exterior primer/paint very easily. The HVLP machine I have tends to warm up pretty quickly, after a while the turbine gets pretty hot. My concern with Latex is the heat would make the paint dry too quickly (again, I haven't tried this to confirm).

The reason I went this route was after using a compressor based automotive sprayer I realized a few things I didn't like. First, my compressor was really taxed and ran constantly. Next, the amount of over-spray was insane and created a huge mess. I found a comparison a while back that showed the efficiency of each type of sprayer, HVLP was the most efficient (around 80% when tuned) with the compressor based sprayers being around 25%. The next thing I didn't like was how big of an air-drier I needed to keep up with the sprayer. I would think this would be an even bigger issue when considering the quantity of paint even just one room would take. Bringing a compressor and drier to each room to paint sounds like a hassle to me.

[Scott T Smith]

So maybe sprayers for automotive have smaller orifices?? Just a guess on my part from the info you provided...if I am correct on this, is there anything else that would be different...if one were to just put in the bigger orifice for the thicker paint, would the gun function the same?

Eric, I have not tried latex through my paint gun, but the oil based industrial enamel sprayed ok after thinning. The main thing that I noticed was that there was a "pulse" to the paint flow, irrespective of the pressure that I set the regulator at. Adding more thinner reduced the frequency and duration of the pulse, but it never disappeared totally.

I did not try this with one of my HVLP guns; the one that I used was the old fashioned Binks clone.

[Forrest Bonner]

I have a 4hp 13 gal CHP compressor that I use for all sorts of things - including powering a conversion spray gun. The gun you chose is important if you want to spray a range of viscosities: be sure that your compressor can output the CFM required for the gun. My gun is an Astro (AOM) X-200 series with a range of tips from 1mm to 2 mm. The 1mm is great for thin paint (waterborne pigmented lacquer) and the 2mm for relatively thick primer. The very thick paint will need to be thinned in most cases. In his book (try Amazon) Andy Charron recommends thinning 10% at a time to get rid of problems with thick paint - like acrylic latex. So if your compressor will power the gun, there really is no difference between using a compressor for car paint and wood paint. You must, of course, be sure that oil and water do not get to the gun and paint pot.
Forrest

[Eric Wheeler]

So if I understand correctly, other than slightly different technologies for propulsion (air compressor, hvlp, or piston pump,) the spray guns themselves are virtually the same provided they have similar orifices?

[Gary Curtis]

After painting 8 antique cars with lacquer, I thought I knew my stuff. I paid an auto body guy who trained at the Ferrari factory. He taught me to sprary. Then I went to work at an airline, and the paint shop guys taught me much more. Their favorite gun was the Binks 21.

A general purpose auto-use compressor should be at least 4hp. 220 volts is almost a must. To minimize heat. Single stage is fine, but falls short when you use air tools or a cheap HVLP conversion gun. . The compressor should give you enough CFM at 90 lbs to power air tools or to spray heavy paints.

The world has changed since '86 when I bought mine. For cars, water-base paints are the thing. Just as with house paint, you need more CFM. I sprayed a fair amount of furniture and used auto paint you find on Porche and BMWs. Glasserit from Germany. My main gun is a Binks 21. Suggested by the airline painters. And I had the small "door jamb" Binks gun. I used that the furniture.

In our dining room sits the Maple laminated top table I sprayed with a Glasserit clear coat in 1999. The finish has endured harsh treatment but remains shiny and flawless after 11 years. It looks like a transparent fiberglass coat. The table was 12 years old when sprayed and the only prep was an automotive undercoat sealer.

I just bought a HVLP conversion gun from Italy to do furniture. One gun will serve multiple functions if you purchase an additional needle/tip assembly to handle heavier house paints. I don't want a Turbine gun because the hose would impede my spraying technique. The hose is too heavy/bulky. The conversion puts out a nice mist with a minimum of overspray.

But my compressor is struggling because of the CFM requirement of the HVLP gun. I would suggest to anyone for any purpose getting the smallest (around 5hp) 2-stage compressor. Running 220 volts, of course. The one machine will do it all.

Get a tank over 30 gallons so the pump doesn't have to work too hard. The last car I painted was a Mercedes. I had $600 invested in the two stage paint, so you don't want your equipment to fail on you while working. To save money, I would buy a compressor with either a dead motor or a dead compressor head and then buy a replacement from Grainger. Used compressors are a dim-a-dozen. Get a good water trap.

Gary Curtis