1940 Ford 1/2 Ton Pickup Project

Show off your work! Anything from final results to full start-to-finish project journals.

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PostPosted: Sun Mar 04, 2012 8:11 am
No, I would not advise that at all. The 12 CFM gun will draw down your compressor so fast that the gun would lose efficiency almost immediately.

Imagine if you can a 12" x 12" x 12" cube. Now stack 12 of them 4 in a row and 3 rows high. That will represent what your gun needs every minute.
Now make a stack of 8 cubes 4 in a row and you will only get 2 rows high and that's what your compressor puts out running full capacity (read continuously). So your compressor is 33 1/3% too small for your gun when ideally it should be 10-15% bigger than your gun so it doesn't have to run all the time.
As your compressor runs it creates heat, heat creates moisture, moisture causes issues with the paint.
1968 Coronet R/T


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PostPosted: Sun Mar 04, 2012 10:27 am
Makes sense thanks for your explanation. I understand your argument about upgrading to a better compressor or doubling the units. However, I just dont have the money to do that right now. (somewhat poor excuse I now considering the project cost). Are there any HVLP guns you would recommend to accompany my compressor?

The reason I ask is because I came across this website.
http://www.spraygunworld.com/Information2/CFM.htm
This is the kind of information that really confuses a beginner like me. I dont have money to waste and am looking to get a good daily driver on the road, not a show car.

Here is a gun set that they recommend with a low cfm.
http://www.spraygunworld.com/Informatio ... IIIKIT.htm

'68 - I appreciate the answers you have provided for me, the "beginner" .

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PostPosted: Sun Mar 04, 2012 1:05 pm
I would like to throw in the summit racing LVLP guns for consideration. Maybe not going to give you the absolute best of the best in putting down a glass-like coat,but really easy on the CFMs.

I know you mentioned the compressors rated output,but what is the tank size?

And the finishline gun says [email protected]'s an air hog in my book.
My programs never have bugs,they just develop new features!

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PostPosted: Sun Mar 04, 2012 3:24 pm
I used one of these when first starting out: http://www.spraygunworld.com/products/A ... VO4014.htm

Bought the kit with a 1.4 for base/clear and 1.8 gun for primer. I still used the 1.8 primer gun today.
1968 Coronet R/T


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PostPosted: Sun Mar 04, 2012 8:06 pm
'68 I've been looking for another primer gun. So I take it that you are pleased with the way it shoots both primer surfacer and epoxy?

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PostPosted: Mon Mar 05, 2012 1:08 am
I use my 1.4 Iwata for epoxy primer though the 1.8 EVO would apply a heavier coat. Normally the 1.8 is used for build primer. Just bought a cheapo 2.5 for poly primer.
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PostPosted: Mon Mar 05, 2012 2:28 pm
Thanks for the replies. Want to understand cfms more though. In terms of my compressor I run an Eastwood sand blaster which requires 10 cfm@90 psi. I am able to go about 5 mins before I lose pressure. How would a paint primer gun compare...13cfm at 40 psi? or even 10cfm at 40 psi? Thanks

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PostPosted: Mon Mar 05, 2012 7:59 pm
Think of it this way. Volume is different than pressure. CFM is a measure of the volume of air being moved.
You can have a 5 gallon tank and a 20 gallon tank both at 100 psi. The pressure is the same but the amount or volume is different.

If you think of the fuel system on a street car verses a race car it may help. The street car may run just fine with a fuel pressure of 10 psi through a 5/16" diameter line however a race car will starve for fuel trying to feed off a 5/16" line and have extremely poor performance. So they increase the diameter of the fuel line to allow a larger volume of fuel to reach the engine. The pressure could be the same but they are pushing a much greater volume of fuel at that pressure.

Now here's why it makes a difference when using a spray gun. If the gun requires 13 CFM for "peak" performance and you are trying to run it on 8 CFM of air, the performance or ability of the gun to atomize the paint correctly will only be optimal for very short time. It will draw the volume it needs from your tank at first but it won't take very long before the "peak" performance is lost. The gun will still be spraying paint out but not fully atomizing it like it was at the beginning.

There are guys that do it this way but in my opinion paint products are too expensive and the prep work too labor intensive for me to be comfortable cutting corners and hoping for the best.
1968 Coronet R/T


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PostPosted: Wed Mar 07, 2012 10:52 am
Awesome explanation thanks so much for your time



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PostPosted: Thu Mar 08, 2012 12:41 am
Checked in with ********** on their primer. A gallon of activator and primer costs $161 dollars. Is that high for the "primer" market?
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