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Tips For Adjusting a Spray Gun

by Donnie Smith

A Few Tips Students Should Know To Produce Awesome Paint Jobs
When it comes to adjusting a paint gun there is no absolute, as it will vary depending on the spray gun and the individuals spraying techniques.  We started using an Iwata spray gun at the school and the students tend to favor the Iwata spray gun.  However, adjusting the spray gun to fit your unique style is the key, not the gun, as I have produced great paint jobs with cheaper guns.

Clean The Gun
Before we start discussing how to adjust a spray gun, I am going to discuss cleaning the gun first.  Most of the problems that you have when spraying paint is a dirty gun.  If the gun is not properly cleaned after each use, it’s not going to spray good, regardless of the brand or how much money that you spend on it.  

The best tip that I can give you for cleaning a gun is to clean it immediately after each use.  Allowing the material to set in the gun too long before cleaning it will make the process a much harder process.  Catalyzed materials have a pot life, which means that the product is going to set up and harden, even if sealed in the gun.  Be sure to check the technical data sheet to determine the pot life of the product that you are using.  Some products have a very short pot life.  So if the pot life is 30 minutes, you need to mix and apply the product in this time frame.  For example, if you are spraying primer surfacer and you decide to go to lunch before cleaning your gun, you may find jelled primer that is going to take much longer to clean after lunch.  If you wait to long, the material could completely harden inside the spray gun....this is something that you do not want to happen.  

Adjusting The Air Pressure
As I already mentioned, there is not an absolute, but you can get an general idea by reading the product technical data sheet recommendations.  However, depending on the spray gun, the regulator, is the regulator at the gun; or are you using the regulator from the wall.  If you are using the wall regulator, remember that there is a pressure drop from the wall regulator to the gun.  Each foot will decrease pressure, which you will need to adjust for.  If you are using a regulator at the gun, which seams the easiest for me, the gauge reading may vary slightly as well.  I am not trying to make this sound confusing, I just want to make sure you understand that there are variables when adjusting your air pressure.  If the recommended pressure from the technical data sheet does not fit your spraying technique, don’t be afraid to tweak it slightly.  

How Do I know If It Is Not Spraying Properly?
Do a test spray on masking paper....but please do not tape paper to the booth wall and spray on it to do your adjusting.  The will leave a ring of paint around the area you are spraying.  This is something that drives me crazy.  We built a stand that holds a roll of masking paper and use that.  You may have another way and that is fine, just try not to get the overspray on the walls.  Anyway, spray your test.  If you have a figure 8, or it is heavy on the top and bottom, your air pressure is too high.  This will also result in too much overspray and waste of paint.  If the pattern is heavy in the center of the fan pattern, the air pressure is too low.  You may also notice that the paint does not atomize properly.  The paint drops will spray out in big drops and cause a heave orange peel surface.  If  you notice this problem, increase the air pressure.  Adjust the spray gun to fit you.  

Fluid Adjustment
This adjust the amount of fluid that sprays out of the spray gun.  This will also depend on the product that you are spraying.  For example, many base coats recommends a medium wet coat.  And many clear coat recommend full wet coats.  To make sure what is recommended, always read the technical data sheet for the product you’re spraying.  It will tell you what kind of coat they are recommending.  Back to the test spray.  If your pattern runs too fast, you probably have too much fluid.  You will need to reduce the amount of fluid being sprayed through the paint gun.  If you do not have enough coverage, you not getting enough fluid.  Therefore, increase your fluid.  

Fan Adjustment
The fan adjustment adjusts how wide or narrow your pattern sprays.  This is going to depend on the product that you are spraying.  When spraying base coat, you want a wide pattern to produce a even medium wet coat.  When spraying clear coat, I normally narrow my pattern slightly to produce the full wet coat, which produces the wet shinny look.  Keep in mind, that when you adjust the fan or fluid, this is going to change your air pressure.  You may need to readjust the pressure when you get it set correctly.  

My Main Point
Use the technical data sheet to give you a good idea where to start.  However, if it is not working for you, don’t fight....don’t try to adjust yourself to the gun.  Adjust the gun to your unique style.  Your technique is going to differ from mine.  And an Iwata spray gun is going to spray slightly different than a SATA paint gun.  

Do you have any spray gun adjustment tips or advice?  I’d like to hear them if you do.  Your tip may be the tip that helps a student get it or fix a problem they were having.  Leave us a comment!


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