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Normally, I'm not a cheapskate. But for some stupid reason, I have been unable to make myself buy a high end air gun. I base my faulty thinking on the fact that the cheap guns are, well, inexpensive. But no matter how well I clean them, they eventually die.

So, my question is, why? Do they corrode internally? Are the expensive guns made out of expensive, corrosion resistant materials? Other than the tips, what makes a gun a good gun?

And which one should I get?

I'll admit, I fear spending $300 on something that will die.

Mike

In my limited experience, expensive guns require better maintenance to continue to perform at the superior level expected of them. Cheap guns generally don't achieve the quality of finish a gun with tighter tolerances will give.
What kind of spray guns are you buying and what is killing them?
Some of the cheap Harbor Freight guns offer all steel construction. They are relatively hard to kill.
I've sprayed a fair number of instruments and a few other things over the past 10 years with a $15 jamb gun. I usually shoot lacquer, rarely do a full break down cleaning and it still seems to work about as good as it ever did. (which is to say "fair") I run a little thinner through it when I'm switching brands of finish, and remove the air cap and soak it in thinner every so often. When I do an "as is" finish it is usually satin, and for a gloss finish I'm usually sanding and buffing anyway.

I found that the needle packing in the cheap guns failed after only 3 or 4 guitars, on the ones I had the seals were a hard plastic and soon started to leak causing a fluttering pattern. I thought that if there were available replacement seals these would not be that bad, but after getting a better gun I was amazed how much better it sprayed and spare parts are available to rebuild them. I also obtained some high quality spray gun lube and oil the needle and other required places after cleaning. Cheap is not always cheaper in the long run.

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Fred Tellier
http://www.fetellierguitars.com
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I've found that cheap guns require excessive cleaning, their seals don't last as long and I don't believe their internal surfaces are machined as well. Not all cheap guns that I have used are problematic, but I've quit buying them. That said, I have never gone to the expensive guns like Sata. For guitar finishing I've found guns in the $100 range to be plenty good and have lasted just fine. I've got a Sharpe FX1000 that works great.

I have found that the main issue apears to be the use of waterbornes. This gun has all stainless on the inside: http://www.sharpe1.com/sharpe/sharpe.ns ... Waterborne

This makes sense to me, but I use a high pressure tank. Can I use a regulator at the gun to convert it? I like the three year warranty too!

Mike (edit: never mind, that is a $400 gun )

I now use this gun with a nylon cup: http://www.spraygunworld.com/products/A ... 20Gun.html

Price is pretty good. I got the kit with three tips and a diaphragm regulator.

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Andy, I like the idea of the all-stainless steel gun. Do you use waterbornes with it?

However, I find that site very confusing. How much is it? Are the single tips $68?? That seems high.

Mike

Mike,

Can you describe what you are seeing with the gun you have? I just did a spray job with EM6000 using a cheap gun. Looking in my gun it looks like the passage is brass. Other than adjustment issue, I think the unlined passage had some potential for contamination (possibly leading to the blue effect that some people see). That is a total guess but I'm questioning the idea of using the gun again.

John

John, the "blue effect" has nothing to do with the gun. Unless you are laying it on too thick. It's due to the property of the acrylic base.

The cheap guns have plate brass. In fact, I believe the internals are cheap steal, with a brass plate, then a chrome finish plate. What I notice is that over time, chrome corrodes, then the same with the brass. Because I eventually get rust. Brass does not, of course, rust (iron oxide). So, I'm going to punt on these for waterborne. I'm going to get an all stainless steel gun.'

Mike

Yes, I spray EM6000 through it (and USL prior to that). The site is ultra confusing. I believe the tips can be found for around $30 if I remember correctly. I have the kit with .8, 1.0 and 1.2 and use the 1.2 for WB. I do wonder if a 1.5 would be better than the 1.2 though. I'm broke at the moment so can't really spend the cash to find out.

The gun is quite nice and this last finish with EM6000 came out very nice with a lot less orange peel than when I was spraying USL. I'm not sure whether that's because of the finish or because I opened my air screw a little bit. If you end up getting one just let me know and I can give you the settings I'm using, which you can use at your own risk of course

The only knock I have on the HVLP thing is that I still haven't figured out how to adjust it to spray fine enough for shading. For that, I use an Iwata airbrush which is the bomb but, even at max range the pattern is quite small. I know it's possible to burst with an HVLP, I just don't know if it's possible with a mid to low end gun. I do spray color through it just not for the actual bursting and whatnot.

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I don’t mean I got the blue effect on the guitar, I actually saw it in the gun. I know the finish has that hint of blue to it, but what I’m seeing is a bit different.

After each spraying session, I would empty the gun.
Spray out the remaining finish.
Add water to the gun and spray that out.
Then add some DNA and spray that out.

At this time I considered the gun to be fairly empty of the finish. I did find that there was always some film of finish if I left things dry so I didn’t consider this a 100% strategy to get all the finish out. I then would add just a bit of DNA to the gun to keep the passage wet. I would also remove the tip and put that in a cup with some of DNA. What I noticed was that the DNA and the leftover finish, with the brass, would turn the solution blue. If I just put some DNA and finish together I didn’t get this. I need to do another test to make sure.



So my thought is that the brass is reacting with a combination of the finish and DNA. My gun was said to be OK for waterbased finishes, but next time I’m going to make sure I get one that is stainless or lined properly. Of course this could be normal and I'm just creating theories for nothing. Which anyone would tell you is the kind of think I do.

Andy, what I'm not seeing is the "tip kit". I think. So, I was trying to figure the total cost. It's really not that low (I think when you add it all up), but that's OK, I think stainless is the answer. I do worry about HVLP. I've tried one with a pressure regulator (cheapie gun) and could not figure out how to get it to mist properly. My lack of understanding clearly showing through. But if I can hook this gun with a regulator to my pressure tank, and it work fine, I'm good with that. Is that what you do?

John, I see what you mean. Looks like you are leaching copper into the finish. Ugh! I have no idea how brass is plated onto a substrate. But that sure looks like a substrate failure. Maybe go to the Target forum and see if there is any talk of this.

Mike

So, this is the exact kit I bought for I think the exact same price ($250) http://www.spraygunworld.com/products/A ... rCase.html

I would consider going with the 1.0, 1.2, 1.5 kit instead of what I got though. I got the .8 tip because I thought it would be useful for spraying really thin stuff.

This kit comes with a good diaphragm regulator. The cheapie "regulators" at bLowes or Home Despot are not actually regulators and are completely worthless for our purposes. I use a run of the mill Sears "5HP" compressor but I imagine just about anything would work well with just about any HVLP conversion gun as their air requirements are pretty low.

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Andy, that kit is really nice. Looks like it has everything I would need.

Just curious as I cannot really tell from the web page. Is the body stainless or aluminum (painted or anodized)?

I'm guessing with the stainless internals, you've seen no corrosion. Have you used it with any nitro?

Mike

The gun body is stainless as well. The set also comes with a rebuild kit which is nice but so far mine's working just fine on the original stuff.

No corrosion whatsoever. Might be worth the extra cash for a SS cup though. I would think that an SS cup is easier to clean than nylon. The nylon one tends to get scratched up and stuff and does pick up color from dyed finish.

I've only run Target stuff through it but I'd imagine it would do swell with nitro as well. I have no desire to go toxic at this point though. If I ever do, it will probably be some sort of polyester anyway.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I can't really comment on the effects of stainless steel or other parts for waterbornes. I don't use waterbornes, but the gun I use ( a Walcom EGO) is supposed to be OK for use with them.


But.......... for anyone who's having problems laying down smooth consistant coats, find a good automotive painter and hire him for a couple hours. Bring him to your shop, with your equipment and have him get you pointed in the right direction for settings, and techniques. There isn't any one magic setting like "26 psi, 3 turns out on the fluid adjustment, 2 in on air". Settings vary with different finishes, different batches of finishes, and different temperatures. Someone who's good with a spray gun can show you what adjustments to make, for whatever problem you're having. There's also no magic formula for "add x ounces of thinner to x ounces of finish" either. Recommendations are just general guidelines.

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I didn't mean to say it, but I meant what I said.
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Andy, excellent! Glad to hear it's SS. The reason I asked about nitro is because some seals cannot handle it. And I believe this gun is specified WB, though no warning about NOT using nitro. Woody, I agree. I can tell by sight and sound if it's going well. And feel (occasionally spray my hand to see what's happening).

I think the issue of using waterbornes in guns that cannot handle water needs more attention.

m