There are several considerations when it comes to a compressor for HVLP guns. As you would suspect, the volume that the compressor can provide is actualy the most important issue. If say you have two comprossors which are capable of producing the same "amount" of air, then the one with the bigger tank would be most important. YOu use a larger volume of air at a lower pressure so to speak. However in practice, the HVLP gun is mostly refering to the pressure at the fluid tip and air cap. This is where the work is done. so ultimatly, you can in most cases get by with the same compressor you would use with a conventional gun. The bottom line here is , if you are painting a car, or something large it becomes a real issue. However when you are painting an airplane, if you can spray a coat on the whole plane without a change in airpressure at the gun, you will be ok. That being said, The more the comprossor runs, the more issues you will have with moisture in the lines and in your finish. by way of example, the best shop I ever worked in, had the same size compressor as most shops, ie 10HP I think it was. However they had a 500 gallon tank for air storage. The compressor would run a long time to fill the tank, but then it wouldnt run again forever,, there were days it would only come on twice during the day. what this does is it allows the air to cool down before you release it. Hence the moisture will be more likely to condense and collect in the bottom of the tank instead of staying suspended in the air to go down the line and end up in your finish. As for what dcompressor will work, read the specs for the compressor, it will tell you the CFM it is rated for. Myself I would want to exceed the need by at least 50 percent to allow a duty cycle and reduce the stress on the compressor. The number you will want to reference this to is the number on the highest tool you plan on using with the compressor, in this case the spray gun. Also keep in mind, that an airhose will dramatically reduce the available pressure at the gun. If you are using a 1/4 inch airhose and its 40 or 50 feet long or worse yet, one of those kinky coiling hoses most compressors come with! you will have to set the regulator at the compressor for something in the neiborhood of 65 to 70 pis to get 45 at the gun. (aproximations here, I dont have my table in front of me that shows actual air loss due to friction) a larger airhose, say going to 3/8 will reduce the problem dramatically.
Bill, your comments about equipment and the quality of same, well yes I totally agree, Most of my wrenchs and sockets are Snap on,, as well as stuff that finds my hand on a daily basis. If it is something I use very infrequiently , I may buy a lesser quality. Steve, with regards to buying inexpensive guns and then you can just throw them away, in my mind, this is like building 5 super clowns to fly stunt with, if they dont fly good just throw it away and try the next one,, lol
You may get one of them that actually flies the pattern fairly well, but in the long run its going to handicap you. ThAs for the buy-ity-now thing, well some sellers are really just running retail stores online under the guise of auctions and dont undestand the dutch auction setup. That and I have seen cases where people will "bid up" theese auctions. However if I were going to try to sucker people that way, I would probably start the biding portion a bit lower, once a bid is recieved on a BUY it now auction the option for buy it now disapears. IIRC.
Bill back to your comment, I totally agree within reason. I would say that knowledge of materials, technique and knowing your tools are very critical, however, knowing that the equipment is not handicapping you , is very important. reduce the variables and reduce the problems. I feel the same way about my flying, I try really hard to have my equipment not be a handicap so that I can judge my flying as it is, and not have to interperated whether its the plane causing the problem or me.
Steve as for different guns for color and clear. Yes the ultimate scenario is to have a primer gun, primers have particulate matter in them and will wear the tip and needle set faster. A color gun, nothing but color, and a seperate clear gun. HOWEver I typically clean my gun good enough that the only time I have a problem is if hte color has pearl, It can be kind of annoying to spray something that is supposeed to be yellow solid color and discover after you spray the clear that somehow you got pearl on your yellow now! (look at my Vector really close) I think I got the questions covered there? I hope this helps, I dont really consider myself an expert, but I have painted custom and production for a lot of years so I know how to make mistakes, and sometimes how to avoid them?
always clean your base surface well, and wear the proper respirator!
Topic: Spray guns (Read 4621 times)