air pressure for HVLP and clear coat

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PostPosted: Wed Jun 16, 2010 4:21 pm
Hi , i am in the process of painting a 40 ford. color and old school flames are done and went slick(base coat is fool proof),but I can't seem to get the clear to laydown smooth. In the clear coat info sheet it has air pressure at 8 to 10 lbs. this can't be, can it ? it says at cap. I take that as the cap where the paint exits the gun.If so ,how does a guy measure pressure there. What should the pressure be entering the back of the gun. I learned on a syphon gun and am new to the HVLP. I have wet sanded the hot rod smooth (clearcoat)again, and am thinking of trying one more time. please help me get rid of the dreaded orange peel. Thanks JS

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PostPosted: Wed Jun 16, 2010 4:38 pm
Use the air pressure that your gun specifies, they're all different.
They list a pressure that will give you 10 psi at the tip, they all need a different
inlet pressure to get that. anywhere from 16 to 45 for my guns (HVLP)
So check your gun recomendations.
And that pressure is measured at the gun with the trigger fully pulled.
You can vary it a little for personal taste
JC

(It's not custom painting-it's custom sanding)



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PostPosted: Wed Jun 16, 2010 5:02 pm
Thanks for the reply. I am using a gun my nephew had while going thru a body shop course at the local college,and I don't think he will have the gun paper work,so I think it is time to by my own gun. How are the 3 pak of Devillbis guns I see on Ebay? The only reason that they caught my I was because I recognize the name(been around a long time),the price,and the fact that there is 3 seperate guns in the pack for around 150.00



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PostPosted: Wed Jun 16, 2010 6:38 pm
The cheap HVLPs I have had easily call for 25 or 30 psi or more at the inlet w/ the trigger pulled, to get 10 psi at the cap. Why not give it a whirl and see how it sprays, start at maybe 25 w/ the trigger pulled or something and see how it atomizes and adjust from there.

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PostPosted: Thu Jun 17, 2010 2:52 pm
hvlp 2 half bar or 36psi
fail to prepare ,prepare to fail.



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PostPosted: Fri Jun 18, 2010 12:40 pm
I just found the specs online and it calls for 2 bar or 29 lbs at the gun,but I may take that up alittle bit more. I test shot a couple of small parts with it at 38lbs and it layed real nice ,so I guess now I get to wet sand and respray the old 40 Ford 1 more time. Thanks all js



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PostPosted: Sun Jun 20, 2010 10:02 am
Re post when you finish with the new presure settings and let us know how it turned out



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PostPosted: Sun Jun 20, 2010 7:46 pm
I shot two coats of clear this morning. I actually added a few ounces (5or 6 %) of reducer to the clear,and even though I have 4 or 5 very sandable sags, The clear finally went on to were i can knock it down with 1000 and buff. that is a far cry from last week when the peel was so bad it took starting with 400 to get the thing smoothed out. It was a super humid morning,but here in Iowa ,if I waited for a day with low humidity,I could not have sprayed until late fall.That's just the cards I was dealt. When I get it polished ,I will try to figure out how to post pics.This car is black with old school flames on the front and down the hood and front door. yellow front,to orange ,to red,and blue tips on the flames themselves. They came out awesome. Is there a link on this site to explain the pic posting?Oh I ended up using35 lbs at the inlet with trigger pulled ,1.3 tip DevillbissGTI (factory recomends30 lbs at inlet). This car has been the car from hell. I have painted bikes for years,and they are a lot less forgiving, because of the area difference. Do you guys know how many square inches of paintable surface there is on a 40 Ford? I think it would have been easier to paint a locomotive!! Thanks all

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PostPosted: Sun Jun 20, 2010 8:34 pm
dirttracker30 wrote:Is there a link on this site to explain the pic posting?


Great question...and it prompted me to document this: Click here for how to add photos to your posts.

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