Corvette400hp

Are high flow air fittings needed for paint guns. I have 1/4 inch fittings but wonder if I can benefit from 3/8 inch fittings.

13611

Depends on your setup. For me, yes, they made a difference. I have a 5 hp 60 gal compressor going through about a 50' brass pipe cooling run. Then into a filter... then my 50' hose that I hook up to the gun. So I loose a lot of pressure at the gun with the way I'm cleaning my air. I couldn't maintain the pressure at the gun with the little standard fittings. I stepped up to the high flow fittings and have psi to spare now.

DUB

I agree with 13611.

It all depends. I have both types of fittings and use them and really do not see too much of a change in my air system. My couplings are the larger high volume couplings in my paint booth...but I have unions made where I can use the smaller fittings if I want to. It all depends on what I am shooting and how I 'feel' that particular day. Using the larger fitting changes the volume of air....HENCE.....HVLP...HIGH VOLUME...LOW PRESSURE.

DUB

Corvette400hp

thanks for the advice. I believe the 1/4 inch fittings are not sufficient for my 28 gallon 5hp set up. it is making my clear a bit clumpy -not shinny or smooth in some places . its driving me nuts but im buying 3/8 fitting tonight and see if it helps. home depot was out so im hoping lowes have them in stock. I will post pics to show what im up against. Any help will be appreciated.

Thanks
Corvette400hp

DUB

The clear application issues can have a lot to do with your paint gun and how you have it adjusted and many other variables.

DUB

Corvette400hp

I thought that might be the case. My gun needs 11 cfm and my compressor puts out 10 cfms. I thought that might have been a problem also. Can you recommend a gun that's not to expensive. I don't want to pay big bucks for a hood fender re spray. I bought my high flow fittings this evening and installed them on the gun and hose but I didn't get to test it out.

DUB

Honestly I can not....all my paint guns are high dollar HVLP guns. The guns I have are too expensive for you scenario.

The gun can possibly be adjusted...just because the compressor creates 10 cfm and the gun needs 11cfm....I am sure the fluid adjustment can be pulled back a bit with good air pressure to possibly better atomize the clear.

Think of it like your water spigot you may use to water your lawn and plants. The water pressure is the same...but ...depending on how much you pull back on the trigger of your water spigot....the water can be misted really fine...or you can fully pull the trigger and throw large water droplets at what ever you are watering.

And not knowing if the clear you are using uses a reducer or thinner...it can also be slightly adjusted....and if the clear is COLD and thick...and not at ambient air temp (70-85F)...this can effect how the clear works also.

DUB

Corvette400hp

Thanks for the help DUB. I am using clear I saw on YouTube. It's called wet wet. Its pretty good stuff. A company called all Kandys sells it. You should check it out. His claim to fame is the clear doesn't die back. It looks wet all the time. It doesn't use reducer just hardener. I installed the high flow fittings and it helped out a lot. It's spraying pretty good. It might have been the weather it was a little unseasonable cold for north Florida. I also changed my 50' hose for a 25'. I changed so much I'm not sure what I done wrong. I will try to post pics tommorrow when it dries. Thanks again for the tips.

DUB

The longer your hose is the more drop in pressure you will get....a shorter hose is better.

I have clears that do not die-back. And I looked at the You Tube video and I will write that with my trained eye...I can see things that most can not ...and I will stick with the clear that I am using. I do not see anything special about this clear. If you like it ....that is all that matter.

Die-back can be stopped by using proper procedures....and one of them is when you are done painting...leave the exhaust fans on ...so the curing clear that is producing vapors....these vapors get exhausted out of the booth and do not linger. SO...IF you leave the car in an environment that allows the curing clear to sit in this room and collect vapors. The sides generally will not die-back...because the vapors are shedding off the panel and going to the floor.....BUT...the top surfaces CAN die back because IF you have NO air movement pulling these vapors out of the room....the vapors will rise up and settle back down onto the curing clear....thus causing die-back. This is why I let my exhaust fans run all night....the cost of electricity is so minor versus a clear that is dull and not crystal clear when I walk into the booth the next day.

DUB

Corvette400hp

can I sand on the clearcoat with 800 grit and bring the shine back or is it the gloss gone at this point.

13611

Yes... but ya have to know what you're doing. You should have an idea of how thick the clear is... how many coats you put on, speed, ect. And when to stop and switch to the next grit paper. But as a yes or no answer, the answer is yes.

Corvette400hp

I put 3 wet coats on the hood. I just don't want the shine to go away and have to reclear.

929nitro

I am not a pro but I start with 1200 to 1500 wet and work up to 3000 and then buff out. Here is a clear targa top I just recoated for my sons 90. Started with 1500 wet on DA and then 3000. Buffed with Mequiars 105 and foam pad on buffer. I take an adult course at a Voc Tech school so I can have access to a spray booth and the instructor runs a body shop days. Most of my vette specific advice comes from this forum and guys like Porchdog and Dub.
As it came out of the booth.



After sand and buff.

DUB

NO!!!!

800 grit is too aggressive.

Please be patient and read what I am writing...I will try to explain.

I know you applied 3 coats of clear...but honestly...that does not mean anything. Why do I 'say' that???? you might ask.

Because ME applying 3 coats is NOT the same as YOU applying 3 coats. It has to do with the gun set-up.

1.) How much volume you were atomizing when you pulled the trigger.
2.) Your travel speed and the distance from the panel.
3.) If the clear required a reducer...thus changing its viscosity...which can change the issues in the first two gun set-up issues.

Also the type of gun you used has a lot to do with it. A HVLP will apply more material than an old gun pre-HVLP era...regardless if it is gravity feed or suction feed. AND YES I KNOW....the fluid volume can be controlled by the painter..but the design of a HVLP gun... if used correctly... will generally apply 85% of the paint in the gun cup...while an old gun would be lucky to get 40%.

Hopefully while you were shooting you repair you also shoot a small test panel the SAME WAY...that way you can use this test panel as a TEST panel to see how aggressive you can go with your sanding due to your gun set-up and painting style.

In certification classes I have attended...I was told by the instructors that I am a 'slow-hand'...meaning that my travel speed across a horizontal panel is slow...but when they check the mils of materials applied...I am spot on. So go figure.

A lot has to do with how 'orange-peely' your finish is. KEEP THIS IN MIND. If the surface is really rough orange peel...think about how much material you are going to have to sand off to get the surface level. In doing so...you are removing the mils of clear that are providing the protection to the basecoat. IF....REPEAT...IF you do not have enough mils of clear...the sun will kill your clear and one day you will see it beginning to 'milk-out' or get chalky and that is the beginning of the END.

So...it depends on the texture of your clear. obviously I am not there and I was not watching you apply the clear...BUT...In some cases...I will sand the car with 800 grit and re-mask it off and apply more clear.

BUT...you can sand with 100 grit and when it has been sanded a little bit...dry it off and see that you are at least dulling it out 75% (so 25% will still be shiny)...then go to 1500 grit and get it to be all dull...then go a higher grit if you desire.

Getting it to shine will be achieved as long as you did not use a 'scratch resistant clear'....which is about impossible to dull out...and if you do...you will never get it to shine again...it is way to hard. But I doubt you used that type of clear.

So this is why it is hard to tell you exactly what to do....you and only you know how much you put on the car.

If this answered your concerns...great...if not ...reply accordingly.

DUB

DUB

All I can 'say' to this is EXCELLENT!!!!!

DUB

929nitro

Thanks. Coming from you that means a lot.

929nitro

Just so the OP doesn't get confused you had a typo I believe when you said you can sand with 100 you missed a 0 for 1000 grit.

DUB

WOW...That is a BIG TYPO MISTAKE.....THANKS for the correction...and I proof read what I write 99% of the time and try to catch errors like that.

I corrected my post with the error.

THANKS AGAIN

DUB