HVLP

Rivethead · #1 05-29-2008, 04:14 PM

At this moment I'm taking a break from painting and wanted to post a few thoughts on the use of HVLP. As I've said in another thread here at VAF I have never used an HVLP spray gun but have been present during the use of them many times. My project has come to the point of wiring and my decision was that it was finally time to paint the interior and then return to the installation of wire. So I spent a day and cleaned out the interior of two and a half years worth of sub assemblies (exaggeration) and began masking. My plan is to use Lt. Machine Gray Rustoleum on the interior parts and in fact have sprayed the tip up parts with rattle can Lt. Machine Gray. Having already procured bulk Lt. Machine Gray I was ready to get my gun out and start. Problem was my spray gun, a high pressure model, was in need of a rebuild requiring a few new seals. Necessary parts as I found out were not available locally and needed to be ordered. When I've got the bug to get something done I don't like waiting around so I decided a new spray gun was in order. I decided it was time to put up or shut so HVLP would be the way to go. I settled on a mid range Warwick HVLP setup for pressure pot use. In this case I want to use my pressure pot rather than a gravity feed since I can see that I 'll be needing to use my gun for prolonged periods of time upside down and at weird angles. With everything setup and ready to go I opened up my can of Lt. Machine Gray only to find that it's about as thick as honey. Reading the can I followed, rather loosely, the directions for thinning and began spraying some of the smaller more hidden parts that I'd removed from the fuselage. That was last night and it was a disaster, I have never seen Orange peel that so closely resembled an Orange in my life. I came home a good deal depressed and Googled ?Rustoleum HVLP? and found a lot of information by people using the combination to paint cars. Long story short it became obvious to me that even though I thought I had I hadn't thinned the paint nearly enough. Another problem found in the search was that thinning to a high degree causes the paint to stay soft for a VERY long time. Armed with my new information I set a plan of action. Per one half gallon of Rustoleum I thinned with one pint of acetone then added to the material actually being used in the pressure pot (one quart) one ounce Japan dryer. Making sure at the time of spraying to have no more than 40 psi delivered to the gun and less than 10 psi at the nozzle I once again began shooting. This time after fiddling some with the settings on the gun the paint laid on quite a bit more smoothly with, as far as I could tell, no over spray. At the time that I left (about an hour and a half ago) the paint seemed to be setting up very nicely. The quality of the coating isn't dead smooth but it is very acceptable for my interior work. However, you rest assured if the coating were on the outside I'd be stripping it off. Overall I think I am sold on HVLP.

frankh · #2 05-29-2008, 05:57 PM

If you need help on setting up the gun give me a call...I painted the whole airplane with a HF HVLP...You my friend have seen the results..

Rivethead · #3 05-29-2008, 08:31 PM

Thanks for the offer I'm going to take you up on it. I've gotten the gun dialed in pretty well but I think there is still room for improvement.

frankh · #4 05-29-2008, 09:48 PM

Get a metal shelf...Anything meatl with a smooth surface that we can lean against the wall for a vertical surface...

We'll have you spraying in no time....My painting coach was the most valuable resource, happy to pass on what I know.

Call me at 715-7568 tomorrow (I get off at 3pm) I should have some time to swing by..It won't take long to get you going.

Frank

DanH · #5 05-30-2008, 07:42 AM

<<I painted the whole airplane with a HF HVLP.>>

Frank, was that one of the 43430 guns? So far I'm having pretty good success with one shooting base/clear, although I'm having to flood the clear a bit to push flowout, even with the inlet pressure turned up for atomization. You find any tricks with yours?

Have a loaner SATA 90 I hope to try this weekend. Should be an interesting comparison. I'm told the SATA is a popular mainstay with the pros. If I can tell a noticable difference I'll buy one, but I doubt it will be 8 times better; around $300 bucks, while the HF 43430 was (I think) $40 bucks on sale.

kenmorris · #6 05-30-2008, 08:22 AM

I painted my plane with a HF 43430. To get a good flow with the clear coat, I added a small amount of reducer. You can also change tips. The tip that comes with the HF 43430 is a little fine for clear cost.

dclay · #7 05-30-2008, 09:02 AM

I?m getting ready to paint my cowl tomorrow using acrylic enamel and a HF 43430 HVLP gun. I have almost no painting experience and have only used it for primer so far. Does anyone have any good nuggets of information to pass along that may help ensure success? I?ve been told that adding about double the amount of reducer that the mfgr. recommends helps the paint to atomize better and produces a better finish.

Thanks in advance,
David

frankh · #8 05-30-2008, 09:34 AM

First off yes i have both the mini gun and the full 20oz gun..The mini gun will paint quite large areas. You can thin down the paint more than it says on the can..In fact is essential to over thin it..My guess would be thats what you need to do for the clear.

First off..get onto www.Hotrodders.com Do a search on HVLP setup or something and you will come to a very good article on how to properly set up the HVLP witht the cigar shaped test pattern..It is essential you do this before you spray EVERY batch.

Like I was telling Jim, you then need a metal shelf ( piece of melamine or similar might also work) that you can prop upright to practice for a couple of sweeps..You need to pass the gun slowly, at perfect right angles at a constant distance. The gun weill be travelling slowly....So much so that if you try to paint a wing horzontally, your arm will be about to fall off by the end!

If you pass the gun too quickly you get orange peel, too slowly and it will run...The dark blue I used was impossible to make it run..the white would run quite easily...Go figure.

Frank

frankh · #9 05-30-2008, 09:38 AM

Turn it up to 40 to 45psi at the inlet to the gun with the trigger pulled and air flowing!

az_gila · #10 05-30-2008, 10:45 AM

Quote:

Originally Posted by frankh

.....
Like I was telling Jim, you then need a metal shelf ( piece of melamine or similar might also work) that you can prop upright to practice for a couple of sweeps........
Frank

Frank, a Stirling paint rep. who spoke at our EAA meeting suggested going to the junk yard and getting a couple of auto hoods.

Cheap, easy to get, and the larger area is much better for practice.

gil A

...or, to translate into Frank's native language... car bonnets...