Paint/Body Corvette Materials, Techniques, and How To

cfm/pressure

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Old 08-04-2014, 08:03 PM
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tgcattle
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Default cfm/pressure

Looking at my compressor it says 11.5cfm@90psi and 13cfm@40psi.
My gun says
15psi=10cfm=6psi cap pressure
19psi=11.5cfm=8psi cap pressure
23psi=13cfm=10psi cap pressure
Now my question is should I regulate my airline pressure to 40 psi or lower my compressor to 40psi to achieve 13cfm? And set my regulator attached to my gun at 23-19-15psi?
Am I making sense?
I believe I am supposed to spray @10psi cap pressure?
I ask this cause I think my compressor is not keeping up or I had my regulator on my gun to high (35psi)
I am in the priming stage right now and I got some dry spray in some areas I need to correct this before base coat step

Last edited by tgcattle; 08-04-2014 at 08:05 PM. Reason: added more info
Old 08-05-2014, 07:53 PM
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Originally Posted by tgcattle
Looking at my compressor it says 11.5cfm@90psi and 13cfm@40psi.
My gun says
15psi=10cfm=6psi cap pressure
19psi=11.5cfm=8psi cap pressure
23psi=13cfm=10psi cap pressure
Now my question is should I regulate my airline pressure to 40 psi or lower my compressor to 40psi to achieve 13cfm? And set my regulator attached to my gun at 23-19-15psi?
Am I making sense?
I believe I am supposed to spray @10psi cap pressure?
I ask this cause I think my compressor is not keeping up or I had my regulator on my gun to high (35psi)
I am in the priming stage right now and I got some dry spray in some areas I need to correct this before base coat step
Professionally speaking...so-to-speak.

You are getting to caught up in the numbers....like many do. These 'numbers' are not etched in granite and HAVE to be followed to the letter. What you need to be concerned about is how your primer is going on the panel.

I do not know what name brand of gun your are using. I have SATA's and have a special air cap that allows me to see my head pressure...and I do this a lot and I do not get caught up in the numbers...because it really does not matter....it does ...but not to the point where I get worried because I am more worried that I can lay down the product correctly.

You can adjust your air pressure, volume control and viscosity to achieve a primer that will go on the panel and not be so 'orange-peely'. Also remember that many times 'things' NEED TO BE changed when you get away from ambient air temperatures which is 70-85 degrees Fahrenheit.

Having 'dry spray' may be in your technique and the choice of your thinner or reducer. NOT watching the primer as it hits the panel...and making sure your overlaps are CONSISTENT...so you have a CONSISTENT layer of primer being applied can be part of the issue. If you are shooting a primer and it is 100 degrees outside...and you are using a reducer/thinner/hardener for 70 degrees...it will dry or flash so fast I could not lay it down fast enough to keep 'dry spray' from occurring.

Have your compressor shut of as a high as SAFELY POSSIBLE...so 90 psi is fine...then regulate at your gun if that is all you have. I have a regulator in my booth that I can set to the correct pressure and compensating to the length of my hose in my booth also...because you will get pressure drop in you hose...depending on its length....BUT...my compressor shuts off at about 110psi.

If you are sucking the air out of your compressor fast and it is trying to keep up with you....you may need a more efficient compressor...or at least stop and let the compressor catch up...and know where and when you paint. You might need to know your compressor so when you are applying the paint. You do not want to be shooting and try to paint and be below the pressure you know you need to have to properly atomize the paint by NOT knowing how your compressor acts.

DUB
Old 08-06-2014, 08:29 AM
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tgcattle
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As i am spraying, initially the spray pattern is good, but as I continue to spray the fan pattern shrinks. This is when the dry spray starts. I have to stop and let the compressor catch up. I was taking 125 psi and cutting it to 36 psi at the gun. I installed a regulator at the compressor yesterday . What I plan on doing is decreasing the pressure at the compressor to my gun and see if it can hold 23 psi at the gun. Devibliss finishline gun. If however I need to stop and let my. Compressor catch up. Will this affect my paint job?
Old 08-06-2014, 09:34 AM
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wall pressure needs to be wide open for cfm flow . if your compressor will not keep up it is just too small. many small compressors claim a lot of cfm but do not deliver it continuously .

also make sure your vent hole in the cup lid is clear. clogged it will act the same way .
Old 08-06-2014, 06:04 PM
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Originally Posted by tgcattle
As i am spraying, initially the spray pattern is good, but as I continue to spray the fan pattern shrinks. This is when the dry spray starts. I have to stop and let the compressor catch up. I was taking 125 psi and cutting it to 36 psi at the gun. I installed a regulator at the compressor yesterday . What I plan on doing is decreasing the pressure at the compressor to my gun and see if it can hold 23 psi at the gun. Devibliss finishline gun. If however I need to stop and let my. Compressor catch up. Will this affect my paint job?
YES it can effect your paint job...and you can not expect your paint job to be RIGHT if you are shooting under different air pressures and having to stop and wait for the compressor to build back up again...which is more than likely getting hotter and hotter and moisture will them be your next 'worse enemy'.

It sees like your compressor JUST can not keep up. This is s problem that can and more than likely will come back and haunt you..>ESPECIALLY when you are clearing the car.

DUB
Old 08-07-2014, 07:54 AM
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Oops
Cap vent clogged
Old 08-07-2014, 08:03 AM
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Also I was going by my old gun psi(35)psi
My new guy states 23 psi
Devibliss finish line
I unclogged cap and lowered pressure seems to have help
Looks like now I can paint the top without stopping and the sides without stopping
Old 08-13-2014, 08:25 AM
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I installed a high flow regulator at the compressor. I set it at 90 psi. I set my gun pressure at 23psi per instructions. I then primed entire car stopping only to refill, no dry spots and the. Spray pattern did not change. It seems my compressor kept up well. I am using a slow reducer. It was around 92deg. I was sweating a lot. Thinking of painting predawn? I would need to change reducer if I do that(76deg) at night.
Old 08-13-2014, 06:39 PM
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Originally Posted by tgcattle
I installed a high flow regulator at the compressor. I set it at 90 psi. I set my gun pressure at 23psi per instructions. I then primed entire car stopping only to refill, no dry spots and the. Spray pattern did not change. It seems my compressor kept up well. I am using a slow reducer. It was around 92deg. I was sweating a lot. Thinking of painting predawn? I would need to change reducer if I do that(76deg) at night.
KEEP IN MIND...If you spray at NIGHT...even though it is cooler...you will encounter an inversion of the atmosphere and when you walk out of your booth or spraying area...do not be surprised that all of the mists and vapors from spraying are lingering/hovering at GROUND LEVEL...and looking like a fog. AND I have seen and experienced that the exhaust from the booth came back down and was being sucked back into the booth again. Basically re-circulating. I do not paint at night any longer...I will start in the morning....but that is just me...because I like giving the sealer/basecoat enough time to flash off...usually longer than instructed...BUT still well within the 'window of time' indicated in the product sheet....I can spend all day on an all-over paint job. I have been known to wait an hour between coats...so the basecoat has more time to flash off....which does aid in the curing of the overall paint job in time.

Not knowing what you are spraying....I know in my system I can shoot the same slow reducer..which allows the basecoat to level out because it is not drying so fast...and give it more time to flash off....even if I started in the morning and it was much cooler than what it will be in the afternoon.

It is all about knowing what you are shooting..how it acts an technique....which I know all about what I shoot and I have plenty of years of technique and practice what I 'think' works. So..it you are new to this...PRACTICE to get to know what you plan to do...so you do not just go and jump in 'thinking' that it will be all right...but you never tested you IDEA first.

DUB
Old 08-13-2014, 09:24 PM
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tgcattle
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I am using House of Kolor system. I will be spraying a silver metallic sealer with kandy apple red basecoat/clearcoat. How long do you estimate to paint the entire car?
Old 08-14-2014, 07:32 PM
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Originally Posted by tgcattle
I am using House of Kolor system. I will be spraying a silver metallic sealer with kandy apple red basecoat/clearcoat. How long do you estimate to paint the entire car?
Not to be a smart@ss...but....AS LONG AS IT TAKES. Start somewhat early and let it 'tell' you when it is done...INSTEAD of you forcing it to get done quickly. NOW is not the time to be in a hurry.

Have you ever shot a candy before???? That is the million dollar question. If you have not...MY best bit of advice it to shoot test panels and get an understanding of it. Because if you go in and just spray away....you may not like what you see. Those of us who shoot a tinted clear or candy....know that technique and knowing how to apply it evenly is where it all matters. And if you have shot candy before...then you know how long it is going to take.

It has been a long time since I shot House of Kolor. And the House of Kolor paints I did shoot were way back in the late 1980's and early 90's. The system more than likely has changed...I do not know. I use another type of candy or make my own candy on my paint service.

The main thing...in case you have NEVER shot a candy is.... YOUR ENVIRONMENT...meaning it needs to be as trash free as possible. Only because ...back in the day....large specks of trash will cause the candy to migrate to them and you can end up with a lot of dark specks in the paint.

I wish you the BEST OF LUCK...Getting a candy job right....all about looking at what you are doing and paying attention.....it is NOTHING like shooting a solid or metallic color. AND....your silver sealer....needs to be prefect due the the candy will show that it is not right if it is not applied correctly also.

DUB
Old 08-14-2014, 08:40 PM
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tgcattle
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Yes I have shot this before. It is not a true candy, but a bc/ cc system that mimics a candy. That is a picture of it on my avitar. It lays out nice.
Old 08-15-2014, 06:40 PM
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Originally Posted by tgcattle
Yes I have shot this before. It is not a true candy, but a bc/ cc system that mimics a candy. That is a picture of it on my avitar. It lays out nice.
You then should have this covered. Just do not be in a hurry to get it done so you can go watch the 'ball game'.

DUB
Old 08-17-2014, 09:48 PM
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I finished my initial sanding and wet sanding today. Pulled off paper and tape. put tires back on and rolled her outside. washed her off good. hosed out garage also. need to tape up again and maybe paint next weekend. Dub, I hope you have some young sanders at your place cuz it sure is a lot of sanding and I still have to color sand. I read that a true candy would tend to fade if left out in sun a lot. That is why I went with the bc/cc candy from HOK. HOK even suggested not to paint a driver with candy. Some day I would like to paint a true candy paint just to see if I can Thanks for you help.
Old 08-18-2014, 06:38 PM
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Originally Posted by tgcattle
I finished my initial sanding and wet sanding today. Pulled off paper and tape. put tires back on and rolled her outside. washed her off good. hosed out garage also. need to tape up again and maybe paint next weekend. Dub, I hope you have some young sanders at your place cuz it sure is a lot of sanding and I still have to color sand. I read that a true candy would tend to fade if left out in sun a lot. That is why I went with the bc/cc candy from HOK. HOK even suggested not to paint a driver with candy. Some day I would like to paint a true candy paint just to see if I can Thanks for you help.
NOPE...I am the sander. And YES...a true candy...so-to-speak is not advisable for a car being driven daily. And honestly...any person who would paint their car in candy and leave it outside all the time....deserves everything they have coming to them.

The masking off is the fun part to me...it allows me to get focused.

DUB

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