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Posted

After using 5-6 cans of aerosols and getting nowhere... I decided to buy a spray gun and shoot clear coats with the 120lt compressor at my brother's workshop. I tried many adjustments on the gun and tried at high and low air pressures (15 to 60 psi). But I keep getting orange peel. A woodworker friend told me it was because I didn't thinned the lacquer enough. The lacquer I'm using has honey-like thickness and I thinned it to milk-like thickness. Should I thin more? What is the normal "thickness" of lacquer to shoot with a spray gun?

Or any other suggestions to prevent orange peel or any helpful tips on using guns would be very much appreciated. Well it is still much better than using rattle cans.. and I can get rid of the peel with sanding and buffing at the end but I think I should be getting smoother results with a spray gun.

I'm using a gun very similar to the "Production Spray Gun" at StewMac and using nitro-cellulose clear (high gloss).. level sanding each day before shooting.. and spraying 5-6 inches away from the guitar.

Posted (edited)

Orange peel is very common with lacquer. It suppositly doesnt lay out as nice as poly urethane, and you can never really get rid of orange peel. Are you using a retarder in the mix? Add like, a half a teaspoon or so of retarder to slow down the drying time and let the surface flatten a bit. As long as you are getting good atomization, don't worry about orange peel. It easily sands out.

I think you need to play with water for a while. Stop what you are doing. Fill the cup with water and start adjusting the fluid valve and the fan knob on the gun. See how that affects the spray pattern and the coverage. Get used to what the controls do.

Also, try using the lowest possible pressure needed to get the paint to atomize. Are you getting orange peel, or a dry coat?

http://66.34.72.138/howto/paint/orange-peel-1.jpg

Some things that can cause orange peel:

Moving the gun to fast.

PSI too low.

Fluid control nozzle closed too much.

Fan control open too much causing a wide coat with light coverage.

Try slowing down your arm motion with the gun, increase PSI or adjust the fluid valve. I can spray McFaddens nitro unthinned at about 35-40 PSI. UNTHINNED. Sounds like you need to do the water thing I suggested if you have to ask this question.

Edited by AlGeeEater
Posted

The first thing I would ask is how do you know it's orange peel and not something else?

There are many many many things that can happen to a finish, how did you settle on 'orange peel' as your particular problem?

Pics would be very good here.

Posted
The first thing I would ask is how do you know it's orange peel and not something else?

There are many many many things that can happen to a finish, how did you settle on 'orange peel' as your particular problem?

Pics would be very good here.

Damn, I wrote that post for no reason yet :D

Posted

First, what kind of gun is it? Sort of like a good gun is like sort of like a Ferrari and wondering why you lose every race. "It's got four wheels and a motor!!"

You're probably shooting too close. At least for me. I hold back about 10"-12".

Are you laying down full, wet coats? And like the previous post are you using a bit of retarder?

I shoot a lot with an HLVP turbine, which most of the finishers here hate, and with properly thinned down and retarded finish I have very little orange peel. I've also gotten a cheap HVLP gravity feed and ditto. For really critical stuff I have a Bink's No7 which is older than most of you all, but I hardly ever need to use it.

I wouldn't recommend using water as a test fluid. I'd use something compatible with what you shoot, like lacquer thinner. Also shoot a test pattern of thinned lacquer on a piece of clean plate glass.

Depending on the lacquer, the temperature, the humidity and the gun you may have to thin it down 50-50 or more. It only matters if you're in a hurry or are trying to make money. Neither of these is real compatible with beginning finishing.

Posted

Thanks for the advices.. I tried again last night but this time I thinned the lacquer more.. and with higher PSI... The results were much better than my first try. Yes I tried it water and thinner on scrap woods before but it's doesnt give any idea how the lacquer will work. It helps you to get used to hold and move the gun though.

This much of orange peel isn't bad.. I was expecting a bit of it and I can easily sand it once its dry. My first try was bad though.. And I think the problem is the drying time of the lacquer. It dries too fast on the surface before set smoothly. I havent seen any lacquer retarder here.. but I will search.

Then again.. its still much better than spending time and money on rattle cans and having lousy results.

Posted
Then again.. its still much better than spending time and money on rattle cans and having lousy results

Whoa, don't knock it until you've tried it. We got a thread rolling around featuring a number of guitars that have been covered with rattlecan laquers, poly, etc. Nothing wrong with using rattlecans.

Posted
Then again.. its still much better than spending time and money on rattle cans and having lousy results

Whoa, don't knock it until you've tried it. We got a thread rolling around featuring a number of guitars that have been covered with rattlecan laquers, poly, etc. Nothing wrong with using rattlecans.

Word. Rattlecans have a place in my heart, at least untill i get a decent sprayer.

Posted
Then again.. its still much better than spending time and money on rattle cans and having lousy results

Whoa, don't knock it until you've tried it. We got a thread rolling around featuring a number of guitars that have been covered with rattlecan laquers, poly, etc. Nothing wrong with using rattlecans.

No. I tried many brands... and %80 of them suck.. The CLOU's are very good. but they are much more expensive ($15 for each can and you need at least 6 cans) than buying a spray gun.. If you already own or have access to an air compressor I mean.

But of course.. its not wise to buy the whole spraying outfit if you aren't painting stuff often. I had access to an air compressor so I decided to buy a spray gun instead of paying money to the rattle cans.

  • 2 weeks later...
Posted

I am done shooting my first guitar. I used the stew-mac gun (made in taiwan and looks like just about all other guns I've seen recently), the Behlen stringed instrument lacquer (which is very thin before thinning). At first I was getting a lot of "orange peel" and a lot of bounce back (the spray not actually sticking but flyaing all over tarnation). I found the overspray was solved by dialing down the regulator at the gun to 35psi (the compressor outlet hose was set to 90psi).

The orange peel was a bit harder to figure out. My friend kept telling me my atomization wasnt right!!! Atomization Shm-atomization!!! those little troubleshooting guides are worthless!!! I tried thinning I tried more distance, I tried wider fan settings, more fluid less fluid, After a lot of trial and error (thank God nitro buffs/sands really easily) I finally figured out it wasnt so much the settings on the gun, as much as how my hand moves over the workpiece. At first I was too afraid to lay down too much material and get a run. After I realized a run was not the end of the world I was a bit more agressive with the liquid. Once I started doing very slow passes over the guitar body, the "orange peel" went away and turned into a beautifully slick wet looking layer.

I think I shot well over 2 quarts, at least one third of that was spent in the air, booth, fan cowling, etc when I had too high a pressure setting. another third went into two very thick coats (which finally filled my poorly grain filled mahagony pores) that were sanded back down to nearly gone. The other third was when I think I finally figured it out.

The big question I had, is how to tell when I'm done. I just decided that it was done today. After the second to last coat, I buffed the surface down and then applied a 50/50 cut of lacquer (as recomended by the Behlen can) and I will be letting that dry for the next week to a month or so (the can says 72hrs). I'll wait until the smell is gone....here is hoping for a heat wave in so cal.

The finish already looks like glass and I havent even buffed it out yet! I love nitro!!! Dont fear the nitro, the nitro is your friend, the nitro wont let you down! Pics will be forthcoming.

Posted
I found the overspray was solved by dialing down the regulator at the gun to 35psi (the compressor outlet hose was set to 90psi).

Christ, you're lucky you didn't blow a hole clean thru the guitar! :D:D

Just ribbin' ya. B)

Actually, even at 35 you're probably losing a lot to overspray and bounceoff, try 25.

I usually shoot at 25-30, usually closer to 25, works great for me, and it keeps more product going on the guitar.

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