Replies

1. 
   Kevin | Feb 21, 2007 11:48pm | #1

   Depends on the type of system you're talking about.

   There is the so-called "true" HVLP system which is commonly referred to as a turbine HVLP. That is a self-contained system which doesn't require a compresser and the way the gun operates is different than a compresser-driven paint set up. I've never used one and will have to defer to someone who has.

   Then there is the so-called "conversion" HVLP system. This is basically a regular compresser-driven spray set up where the gun has been reworked or converted (thus the "conversion" designation) to operate at much lower air pressure than a non-HVLP gun is. These I've used extensively.

   Spraying finishes is a distinct art form apart from "finishing" per se in that there is a unique skill set required to maximize the potential of spraying your finish as opposed to wiping or brushing on finishes.

   Then there is the issue of why type of spray set up one is talking about. Each is quite different. There is a pressure pot system where you load your finish material into a pressurized pot which delivers the material and air to your gun via hoses. Then there is a cup-gun set up where the finish material is poured into a cup which is attached to the underside of the gun and from which the movement of air over the top of the feed tube causes the material to be siphoned up and into the gun where it is then spraying onto the surface of whatever it is you are spraying. An alternate form of this type is a pressure cup gun where little air hoses pressurize the cup so that it functions basically the same as a pressure pot system. Then there are gravity guns. These are spray guns which have a container attached to the top of the gun into which you pour your material and gravity is the force which delivers the material to the gun and ultimately to your surface.

   I personally LOVE gravity HVLP guns. They are incredibly easy to operate and are much, much more forgiving than any other type of spray set up, IMHO. The downside is largely that they only contain so much finish material and thus really aren't suited to spraying large areas. On the other end of the spectrum... I absolutely loath siphon-feed cup guns. They require so much air movement in order to siphon that it really severely limits your options once the material exits the front of the gun.

   
   

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   Edited 2/21/2007 3:52 pm by Kevin

2. 
   InMyOpinion | Feb 22, 2007 01:46am | #2

   Hello.
   Your question smacks of the recent forum question about which tablesaw to buy. A small book could be written in answer to the questions. If, as with the other question, you receive only a few answers, it is not for lack of knowledge or desire to help . . . rather, where to start the discussion. Those folks really in the know realize the complexity of the Q&A; and, therefore, may be doing you a service by being brief or absent. A reasonable amount of more information from you coupled with more specific questions may reap better answers.

   Books by FineWoodworking and by A. Charron are a good starting point . . . yet an incomplete answer, and cannot address your previous spraying/finishing experience, the degree to which you enjoy learning a new skill, etc. etc.

   All details aside, HVLP will speed the putting down (covering) of product vis-a-vis what you're currently doing. I mean that literally, i.e., if you and I each start with a similarly prepared board with you brushing and me using HVLP, and I am honest about all my time beginning to end, you will win the race; and a third party will not be able to differentiate your work from mine (assuming we're both skilled). In fact, I've spent considerably more money and must have a greater (broader and deeper) knowledge and skill than do you to compete. If we raise the square footage to be covered, then I will win.

   The very substance we are applying affects the details and terms of my hypothetical situation. To do well in the contest, I have had to learn a lot about guns, compressors, turbines, finishes, paints, viscosity, toxicity, and more. Help is not readily available either. Paint retailers are busy helping customers with color selection and fundamental designer questions. A good salesman doesn't want to know the detail you're are seeking. True, the EPA et al. are compelling the use of HVLP (vs. airless for example--with all kinds of overspray). But the trend and some equipment are relatively new and complex. The end user information is thin and somewhat impacted by (again) the governmental squeeze being apply to products, such as lacquer, for which spraying has gained its fame. At best, there is considerable trial and error (Let's call it "art") in using HVLP.

   To be happy using HVLP, one has to really want to take on the vicissitudes. I recommend using HVLP, but I love challenges and details. Many woodworkers are averse to finishing their work . . . and understandably so. I agree with whoever said finishing time is often about as long as the pure woodworking time on a project. HVLP and other spraying techniques will shorten the time necessary only on multi-coat, larger projects. But the tendency is to forget the time that went into the learning curve.

   May the Force be with you.

3. 
   Mumda | Feb 22, 2007 03:02am | #3

   My fast answer:

   I have this set-up: http://www.gleempaint.com/hvcongunw2qr.html

   It works great at giving me a professional looking finish.
   It is relatively cheap compared to many others.
   I learned how to use it in 1/2 day.
   It saves me countless hours.
   I use it to spray stains & dies, sealers, topcoats and toners.
   I use waterborne varnishes, lacquers and dyes.
   AND IT WORKS GREAT WITH MY 6 GALLON PANCAKE COMPRESSOR!

4. 
   InMyOpinion | Feb 22, 2007 05:20am | #4

   Strongbow,

   Mumda, I think, makes some excellent points. The Gleempaint/Wagner gun setup (without looking further than the site provided) looks good. If and when you search through manufacturers and gun vendors for your equipment options, that one is not going to be among those you first encounter. Thanks, Mumda.

   Gravity feed guns prevail when it comes to availability and publicity, and are driven by the automobile painting industry. You may want to understand the difference between pressure, gravity, and suction guns (from books cited).

   Wagner makes me nervous. I've owned one of its airless as well and HVLP outfits, and feel it provides a relatively inexpensive means of learning. However, I don't believe Wagner equipment is particularly good, and I do believe its customer service/advice is amateurish, especially in view of its self-praise about the service.

   It seems Mumda shoots material of relatively low viscosity exclusively. That is the way HVLP is usually employed. It is worth noting, however, for at least two reasons: 1) The lower the viscosity, the easier HVLP is in providing excellent results. Some folks are quite content doing so with guns costing $100 or even less; 2) The use of a small compressor opens yet another aspect of the HVLP world.

   You can be sure Mumda is spraying small areas (yet another element to factor into your decision). To atomize a liquid requires a mathematical product of air volume and pressure of a certain minimum magnitude apropos to that liquid. It is the pressure that causes most of the overspray. HVLP reduces overspray via High Volume low pressure. Spraying of much duration requires a tank of relatively large size. I have sprayed HVLP from a 2.6gal compressor, but we're talking practically short bursts.

   P.S.
   Strongbow,
   If the style or substance of my writing is not to your liking, *please* do let me know (, and I'll stop).

1. 
   Mumda | Feb 22, 2007 08:22pm | #5

   "You can be sure Mumda is spraying small areas..."

    

   Actually, I've done a couple refrigerator panels and a good size table top using that Wagner/pressure pot set-up with no problem.

2. 
   Strongbow | Feb 22, 2007 10:33pm | #6

   Seems you have covered some good points, although I don't see anyone jumping up and down saying spray finishing in general is worth the investment. From what you say it seems like I should buy one and try it, as this will be the only way I will find out to my satisfaction.

   I would consider that maybe spray finishing was a progression from the long process of hand finishing, and would bring the skill into the 21st century, using updated methods.

   I'll invest in one and then let you know.

    

1. 
   user-83153 | Feb 23, 2007 05:22am | #7

   Strongbow,

      If you are going to invest in a spray system, try this site. http://www.spraygunworld.com/Information2/Woodworking3.htm

     I have no affiliation with them, but learned a lot on the site and eventually bought my SATA RP(not hvlp) gun from them for quite a bit less than I could find it anywhere else. It is the only professional painter geared site I know of that has an entire section to help woodworkers make an informed decision.

      Rob

1. 
   Strongbow | Feb 23, 2007 09:19pm | #8

   Rob,

   Thanks for that info.

   I looked at the site and found it very informative.

   Once again thanks for the help

   Mike