Hi, I would like info on spray guns. The gravity flow is a first time for me, and I will go back to syphon feed, unless someone can convince me not to. I did not do good with either of my G flow guns on the single stage painting. I have done better with a rattle can. I tried every thing, but nothing worked. thank you Les
Hi Les,
What kinds of problems are you having?
If the gravity flow gun is not performing as well as your old gun, I'd guess that something is wrong or not adjusted correctly.
I had to get used to the "feel" of the gravity gun. Changing from something you're used to and successful with can be difficult. In my opinion, the old style guns can't match newer gravity spray guns for transfer efficiency and atomization. Using less paint, putting less out into the environment and getting a smoother finish are things worth the hassle of the change.
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Jim "Oldgas" Potts
Your host and moderator
The HVLP system guns (including gravity flow models) are by far the best, but they do have a learning curve. What worked for me is to paint a test panel to determine flow-out and coverage. I have used a Sharpe SGF for 15 years, and just got a Sharpe Titanium gun for color and a Sharpe T1 for detail and touch up. Have had fantastic results! You can find a good used gun on Ebay very reasonably, and with a bit of practice, your paint will be professional quality!
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Robert Usrey
Hi,guy's sorry for taking so long in this reply. I, just an amateur has bought two hvlp in a packet. one primer, and one for finish. Like I said ,I have got by on farm things such as tractors, and the like, but nothing that would meet concourse,although they satisfied me. A friend is helping do the painting. He has painted his cars, and they look fine, but he is like me , new to gravety feed. The job turned out bad no matter what we tried. yes, orange peel was present indeed, plus pits. The paint store that I had bought them from said the paint was to thick, and should be reduced down to 50% to where it would be thin as water.They also said to try the primmer gun. The primmer gun didn't change any thing. The paint store that I bought the paint from said that I couldn't reduce the ful-thane urethane any more than 25%,so that is where I am at this time. Les
I agree I switched to HVLP recently and the difference is unbelievable. Some things I noted as I started using the new gun was a difference in pressure versus flow. With higher volume and lower pressure you have to make sure you have no significant loss of air flow through restrictions in the line. I changed to 3/8" hose versus the 1/4" I had used for years. I also changed the quick connect fittings to oversized which kept a minimum of 5/16" at the smallest place. You also must play with the pressure at the gun to achieve optimum flow of the liquid. I also had to watch viscosity of the liquid as the hvlp I am using likes a higher viscosity versus the Binks gun I used for years. I wish I had tried this years ago, but like many people I was afraid of change. Hope this helps....if you give more specific problems I might be able to help or know someone who does.....Rich B
Les:
Generally speaking . . .
If you have 'pits' - you need to clean the surface better. This is normally a reaction to oils/silicone left on the surface. Especially if you also have orange-peel.
Orange peel is simply too much paint being applied at one time. (Reduce the paint flow and/or back away from the surface.)
Make sure you mix your paint to the manufacturers specifications. ALWAYS get the MSDS sheet for ALL the components of your paint system. That means the paint, the thinners/reducers and any additives that may be needed. The paint store HAS to have these available - even if they have to print them for you off of their computers!
Use a mix-stick or the cheap plastic mixing containers with the ratios printed on the side to get your mixing ratios perfect.
Have adaquate air-flow to the actual gun. The best way to make sure you do is to have a small adjustable pressure guage right at the air inlet on the gun itself.
Set the pressure at the wall/compressor about 5- 10 lbs higher than recommended and final-adjust it to the recommended spec at the gun.
You WILL always have a pressure drop over the length of the hose you are using. The only way to know if you have the correct pressure at the gun - is to have a pressure guage at the gun!
Do not adjust the pressure at the gun once it's set. If you need to thin the paint - pour it back into you mixing cup and adjust the entire batch there. Then try again on your cardboard.
Always use a pressure regulator and water separator bwtween the compressor and the gun!
Always check your spray pattern on a scrap piece of cardboard. This is where you want to work on distance, flow and stroke - before you start on the actual part to be painted.
Do all you adjusting for flow and pattern on the cardboard. This eliminates messing up the surface of the part being painted.
I hope this helps . . .
Jim
Hi Jim thanks for the info. I went back to the gun after the encouragement from you guys, and I think that I will be pleased with some practice. After spraying some not too refind pieces of farm items,it has done well. My bigest problem was not enough air at the gun. After thinking about the longer hose,and udjusting the pressure accordingly.it worked. leswarner