paint gun tip size

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PostPosted: Fri Jun 24, 2005 1:35 pm
absolute newbie to autobody restoration. I bought a econo spray gun and don't know its tip size. I have read about tips sizes on here and the importance of it. Where is the tip size located on the gun ? I need a 1.3 to 1.5 according to the epoxy prmer spec sheet MP170. Would my purchase come with this tip ?

Also, after mixing in the activator, am I all set to go ? The spec sheet says I can add acetone up to 10% to the RTS MP170. What does this mean and and what does acetone do. It there anything else i may need to add ? How do I know if I have the proper viscosity or is this not important for an epoxy primer ?


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PostPosted: Fri Jun 24, 2005 2:23 pm
What gun brand is it? It should say in the manual, if not mine has 1.4 printed on the needle, where the brass stopper is, though it will vary with guns. With epoxy primer I would spray with a 1.5 or 1.6 if you can find a cheaper gun for just primer (using a primer before basecoat can leave a film in the gun) for my setup I have a 1.3 Sata RP digital for my basecoats and clears, then for the primer I use a seperate 1.6 for my epoxy and primer surfacer, I then have a seperate 1.9mm tip gun for spraying the sprayable polyester putty, which I rarely use.

you can add up to 10% accetone to the epoxy mixture to make it flow out more, leaving it smoother, however this will require more coats since the accetone thins it. However if you are stuck with a smaller needle than a 1.4 you will probably have to do this. As long as you are using the tech sheets recomdations your viscoity should be fine, like I said above you can teak it with the acetone so it performs as needed.

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PostPosted: Fri Jun 24, 2005 9:41 pm
I use Iwata 400 1.4mm for base & clear and transtar 1.7mm for primer surfacer.
I'm a newbie

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PostPosted: Fri Jun 24, 2005 9:54 pm
I use a 1.3 or a 1.4 tip FOR EVERTHING,...really the tip sizes are to be considered RECOMENDATIONS, not a RULE.

lets say you have a too large tip for the thickness of paint you are shooting, you would ADJUST the fliud knob IN (less paint), and your painting stroke somewhat to compensate (a little faster stroke the larger the tip), if the tip was too small, just add a bit more reducer, and open the fluid knob more, it's not like it's gonna FAIL if you use a different tip size than RECOMENDED.

for clear coats and base coats I like a 1.3 tip, but I like to shoot kinda slow, I know another painter that will only use a 1.7 tip for clears, he shoots REALLY FAST, so it works, it's a very personal thing.

hell I use a detail gun with a 1.0 tip for MP170 epoxy ALL THE TIME, I don't even reduce it any axtra, and it shoots it just fine.

so don't get all freaked out about tip sizes, just PRACTICE ON SOMETHING WORTHLESS FIRST,...thats my advice for any "I'm a total newbie" get an old fender, or hood, or just use a tool box, the garbage can, and old box, it really doesn't matter, all you need is something to shoot some different paints through the gun , and get a feel for it.

"I believe the state of arkansas flag colors should be,...................PRIMER"

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PostPosted: Fri Jun 24, 2005 10:08 pm
The only downside to this is if you have lets say a 1.3 tip in a sharpe gun and you spray the highest solids clear you can get... it is going to over atomize the clear and you will end up spraying more of it in the air than on the panel.. A 1.5 in this same sharpe would be like a 1.4 in a Sata, or a sata copy... I have had this happen to me, plus if you are shooting a big project it can double the spray time in the booth... Like I said just had all this happen to me last week... Went up in tip size, clear laid down better and it cut my spray time in half...

Reckon do you ever have dieback problems when you reduce your clears?? I have had that happen before?? Just curious

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PostPosted: Sat Jun 25, 2005 10:35 am
I never reduce my clear coats, except some kandies, or tiny spot repairs
but using a REALLY good urethane grade reducer should prevent die back
"I believe the state of arkansas flag colors should be,...................PRIMER"

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