Sprayguns - HVLP verus Conventional.

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Hi to all,

I'll bring you up to speed on HVLP versus conventional gravity feed production refinish sprayguns. HVLP guns have been around quite a few years now and with their arrival on the refinish scene, they created somewhat of a revolution around the world. Their big claim to fame, lies in two areas. One, they use less material than a conventional spraygun, and two, they create less fumes when you are applying the paint to the surface. By fumes i mean the clouds of atomized paint that are produced when spraying paint, and fill up your spraybooth or room in which you are spraying in. And that's it. That's really all an HVLP gun has over a conventional spraygun. HVLP means high volume low pressure. The concept of a HVLP gun revolves around how the paint you're spraying is atomized through the gun nozzle. HVLP guns atomize the paint differently than conventional guns because the nozzle or setup design allows for more volume of paint to be atomized, but sprayed at a lower air pressure.

It's all to do with the transfer efficiency rate (TER) of the paint you're spraying. What is TER. You start with liquid paint in your paint cup, and that paint is to be applied to your panel you're spraying. You want to apply that paint in the most effective way you can from gun cup to panel. You don't want to waste your paint when you are spraying it on by letting it end up in the atmosphere around you, and not on the panel you're spraying. That's what TER is all about. It's getting that paint on your panel, with minimum wastage. HVLP guns have a better TER than conventional sprayguns do, and hence, use less paint material when spraying. That's the big thing that's wowed the refinish world over the years, less paint used, less wastage, and less fume created.

I say, big deal to that. Why? Because i've used both types of gun over the years, and have gotten the same results that I've talked about above by using my conventional guns. How so you say. It's all about the gun technique or the manner in which you spray your paint on your panel. When HVLP guns arrived on the scene many years ago, spraypainters had to be reeducated in how to spray with them. You have to use a different gun technique with an HVLP gun. Firstly, you have to use a much faster stroke speed and secondly, you have to hold the gun at a much closer distance from the surface of the panel you're spraying. These two things are crucial to using the gun. You have to do these things. There are high solid clears and medium solid clears around today in the 2 Pack clear scene. When spraying with an HVLP gun, you can apply 1 to 1-1/2 coats of HS clear, or when using MS clear, 1-1/2 to 2 coats of clear is all that's needed. HS clear was brought out to work in conjunction with HVLP guns. When spraying with a conventional gun, I like using MS clear, and I apply 2 coats of that under most situations. Sometimes, I may put on 3 coats when needed for a better film build.

Now here's the thing. These two gun techniques mean that you are going to get a much better TER when applying your paint, but ever since i started using conventional gravity fed sprayguns many years ago, i myself have used the same gun technique of faster stroke, less trigger pull and closer to the panel, and got the same results as with an HVLP gun, that is less paint used and less fume created. I have proven that the secret lies in gun technique or how you apply the paint to the panel that matters. That's why i come back to and prefer to use a conventional gun over an HVLP gun. I get better film build control, and better flow control, because i use the similar HVLP gun technique of faster stroke and closer to the job with less trigger pull, when i spray. I end up using much less paint and get less fume when spraying. It's all in the gun spraying technique for a better TER. It's well known that the further you hold your spray gun away from the panel, the worse your TER becomes, the closer the better your TER is.

So lastly,for example, have a look at the Sharpe conventional guns. I would be wanting to get a 1.4 setup for basecoat and clearcoat applications. Look at Razor and Finex FX 2000. I think Finex was what Turtle (Kevin) ended up with.

Your references -

http://www.sharpe1.com/sharpe/sharpe.nsf/Page/Finex+FX2000

http://www.sharpe1.com/sharpe/sharpe.nsf/Page/RAZOR+Conventional

Many thanks,

Greg.:)

 
Nice explanation Greg! I did get the Sharpe Finex 2000 conventional gun and love it. Definitely a good priced quality gun. Makes spraying easy. Seems to be a very forgiving gun. Thanks for all the help in choosing my gun.

 
Nice explanation Greg! I did get the Sharpe Finex 2000 conventional gun and love it. Definitely a good priced quality gun. Makes spraying easy. Seems to be a very forgiving gun. Thanks for all the help in choosing my gun.
Hi Kevin and thanks again. I'm glad the new gun worked out good for you. It's interesting that you've taken to it so well and like it's performance and the results it brings. To me, that backs up my own personal opinions on what great results you can get with conventional sprayguns. I know that if your not a professional painter, using an HVLP gun can be rather tricky and difficult to get a good finish and plenty of paint on the job as well.

Cheers,

Greg.:)

 
Greg, Thanks for the great post and explanation. I will definitely look at the guns you mentioned. The 1.4 nozzle seems to have become the standard for BC/CC as the Sherwin Williams rep told me they standardized their paints for a 1.4 nozzle several years ago. I need a new gun and more trigger time. The gun is easy. Another car is more problematic. I'm out of space and the budget department is against another "investment". Thanks again for your help.

Chuck

 
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