I do 3 coats of clear, let it sit for a week, wet sand with anything between 400 and 800, then re-clear with 3 (or more) coats. Then sand and buff.

1 coat is just not enough.

People think that by doing 3 coats, then 1 coat later that they have 4 coats to buff on. Not true. They are buffing on only 1 coat.

 

Flow coating clear was a method used many years ago to try to get better results from lower quality products. Today's urethane clears are far superior, and applying the correct amount one time. will give you great results with plenty to wet sand and buff.

 

I'm just having trouble with high solids clear. Didn't know if it would help.

 

High solid clears are tough to spray without proper equipment. Are you using the product as recommended on the directions? Tip size, air pressure, air volume, temperature, booth conditions all play in the outcome of your job.

Did you have all the solvent pop sanded out from the first job? If not, that is the problem re-clearing.

 

I never spray more than 3 or 4 coats of clear... Wet sand with 1500 and sometimes with 3000 after that and buff. And I only spray two coats on normal insurance collision work that won't get wet sanded and buffed.

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And I've never heard of flow coating clear?


Nik

 

I see your a ppg guy. I usually spray jc630 as it lays on flat and holds up well. What ppg high solids do u use

 

Having the proper tools are critical for things to turn out right and using the correct methods. Spray gun, tip size, air pressure at the gun and air pressure at the tip. There is a special tool to record pressure at the tip. Having clean dry air with nice filters on all the air lines. Proper Paint booth, Proper prep. Proper mixing for the temperature and type of material being used. Proper spraying technique. We have a chart in the control room that we record what tip, pressure, flow and gun for base, primer and clear. Having the settings logged are nice for a quick reference for what works in case you decide to try something different. You have a base line to go back to if it doesn't work out. The conditions have to be reproduced the same way every time to be consistent with your paint jobs. We use nice digital gauges that attach to the gun to read the pressure coming into the gun and to read the pressure when the gun is spraying. They're kind of expensive but worth it imo.

I've taken some classes through PPG on how to setup the guns and how to spray and some other things... We usually run our guns wide open and control the flow with air pressure. I have my base gun (HVLP) set at 18psi when the trigger is pulled and set the pressure coming into the gun about five pounds higher. So I'll have 23psi at the gauge and it will drop to 18psi when I pull the trigger and stay there. This is how ppg told us to set the guns up. It has been working great for us. You do need the correct size air lines and a compressor that can keep up to be able to do it this way. I spray clear at 21psi and have about 25 psi coming into the gun. Obviously it will be different for everybody.

Waiting the same time between coats is important. We usually set a timer as soon as we come out of the booth. 10 minutes is the standard flash time for us for base and clear. The proper hardners and reducers must be used.



A couple pictures of our booth and mix room.

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Having the proper tools are critical for things to turn out right and using the correct methods. Spray gun, tip size, air pressure at the gun and air pressure at the tip. There is a special tool to record pressure at the tip. Having clean dry air with nice filters on all the air lines. Proper Paint booth, Proper prep. Proper mixing for the temperature and type of material being used. Proper spraying technique. We have a chart in the control room that we record what tip, pressure, flow and gun for base, primer and clear. Having the settings logged are nice for a quick reference for what works in case you decide to try something different. You have a base line to go back to if it doesn't work out. The conditions have to be reproduced the same way every time to be consistent with your paint jobs. We use nice digital gauges that attach to the gun to read the pressure coming into the gun and to read the pressure when the gun is spraying. They're kind of expensive but worth it imo.

I've taken some classes through PPG on how to setup the guns and how to spray and some other things... We usually run our guns wide open and control the flow with air pressure. I have my base gun (HVLP) set at 18psi when the trigger is pulled and set the pressure coming into the gun about five pounds higher. So I'll have 23psi at the gauge and it will drop to 18psi when I pull the trigger and stay there. This is how ppg told us to set the guns up. It has been working great for us. You do need the correct size air lines and a compressor that can keep up to be able to do it this way. I spray clear at 21psi and have about 25 psi coming into the gun. Obviously it will be different for everybody.

Waiting the same time between coats is important. We usually set a timer as soon as we come out of the booth. 10 minutes is the standard flash time for us for base and clear. The proper hardners and reducers must be used.



A couple pictures of our booth and mix room.

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I would love to be able to paint something in a booth.

 

with my new iwata and spraying jc630 it is at 28psi and the fan 2 turns in from fully open. The fluid control is 2.5 turns out from fully closed. It lays slick and needs no cut and buff. I tried shop line high solids with that set up and it was horrible. Tried bumping psi up to 33-35 and it didn't help

 

We started out like you. In a garage. Then we made a "homemade paint booth". Then we came across this Pressurized Downdraft Garmat Booth about 8 years ago. Our paint rep told us about a Car Dealership that was relocating and was leaving everything in the facility behind. We got it for free minus what it cost to pay some people to help us tear it down and move it to our location. My dad and I set it up ourselves. Pressure washed everything and put a coat of paint on it. It has a 1.2 million Btu furnace so we can bake the paint at 140 degrees for 30 minutes and have a car finished and cured in a day. It also allows us to maintain and proper temperature in the booth during the winter. Garmat said it was there best $70,000 booth at the time. We were extremely fortunate to get it. We would have never been able to afford one any other way..

Nik

 

I would build a paint booth but have no room. Id say im gonna stop messing with high solid clears and just keep spraying the jc630. I just hate not being able to do something correctly. I am working on some ideas for some drop type white tarp ideas in my garage to let down and hose off before I paint to help with the dirt.

 

What made you decide to stop using the jc630?



Nik

 

Oh nothing. I just bought 4 gallon of it on sat. Just wanted to be able to offer a better clear coat. I like the 630 since im use to it. Never had a car come back from it so it must work well. I would like to try
ppgs 2021 clear as well. My jobs are priced cheaper so it don't leave much room for a better clear so I have not had much practice with high solids. The shop line high solids 2:1 euro clear is what I was trying. Its so thick

 

The jc630 is some of the best clear i've used, even compared to higher priced clears I honestly can't tell much difference other than the price tag.. We've used it exclusively for about 5-7 years and have never had a problem with it.

Stick with what works..

Nik

 

No booth here, just a walled off section of my shop (16x54). I just like the way a "3+3" looks. Works for me.

 

No booth here, just a walled off section of my shop (16x54). I just like the way a "3+3" looks. Works for me.

What do u mean a 3+3. And yes that car looks slick

 

Looks good. Seems like a twice the time, money and materials for the same finish though. jmo.

 

3 coats of clear. Sand and 3 coats of clear...

We're not spraying Lacquer anymore people! It's a waste and not recommended. Two coats is all you need with todays clear. 3 at the most. Anything more than that and issues will start to pop up. Solvent pop being the main one and durability issues.

I do not advise doing this nor does PPG.

If it was so. PPG and other Paint companies would specify so.

Nik

 

What grit sandpaper do you use on the 3+3 ?

 

Id say 800 or so. cut it fast and still be able to bury the scratches with clear coat.

 

Thanks Nik , I'll give it a try .

 

On my "double dipping" I wet sand with anything between 400 and 800 grit, whatever I have on hand at the time.

Finding out what works for you is key, no 2 painters are the same. Some are fast, some slow. Some are heavy (thickness), others aren't.

Something I found that helps is having a lot of pressure "at the wall" then choke it down at the gun. I run 130lbs where my hose connects and then regulate it at the gun to what I want.

For production jobs, 2 good coats, buff and ship is good. For special jobs, I like the extra UV protection of more coats, with the second round of clear being slicker for less aggressive grits for buffing. Just the way I do things. Your mileage may vary.

My old boss used to tell me, "Wanna start an epic argument? Ask a room full of painters how to paint!"

 

I think the best way to determine how much to put on is to test with a mil gauge after you have cut paint.

There are a lot of variables and human input that can make 3 coats equal to 5 coats in another shop.

You can have the deepest looking finish that is on the verge of failing and have almost zero clear film on it. You could also have the opposite. Without checking you are simply guessing and I won't get into that.

Try HOK clears that are made for high builds due to many colors and layouts in custom paint jobs. They flow out amazing and like to build vs 2 heavy coats of a collision clear that are meant for speed and light buff and deliver.

Custom work is different then production work. Also picture don't show proper build films. Also waiting a day or 2 days might also effect adhesion with some clears as they aren't meant to be used for custom work.

Good luck!

 

Lots and lots of great information here. Nik has done well explaining several different things. I would caution only one thing though, when he is giving his air pressures both at the gun and at the nozzle, that is for his gun. Not all guns are the same. Sata's are air whores as we all know, Iwata's not as much. My LPH400 only wants 16-18#'s at the gun, but my RP 1.2 wants 32#.

Revolver is right about arguments on painting. There are so many different ways, as long as in the end the job looks good, then they are all right. The one thing of his comment I question is about cranking air pressure at the wall. With my trigger pulled on my gun, I then adjust the regulator at the wall to what I want at the gun. This way I have even and consistent air pressure all the time. Have any of you ever been painting and then halfway down the length of the car the air pressure drops? That is because the compressor is running out of air and the wall regulator is full open. If a good diaphragm wall regulator was only giving the gun what it needed then you would never feel this pressure drop happening.

I can't remember the last time I flow coated anything. I usually spray 4 coats of clear waiting proper flash times. After a bake I will wait a day or so and sand the clear with 600, then let the car sit for a week. This opens the clear and will let all the solvent escape and will stop any pinch back from happening down the road. Ever buff a car quickly after paint only to have it pinch back a week later? It takes upwards of 7-10 days for all the solvents to flash out of a paint job. Once that is done I work my way up to 3000 and then buff. I know 5000 is out now but have yet to try it.

Another thing to remember about clears, while they all may look good after a sand and polish, or out of the gun, the true test of a good clear is down the road. The cheapest crap out there can be polished up nice, what matters is how long it lasts. All clears, even all PPG clears are all so different. One of the most expensive things in the can is the UV screener. Now ask yourself why one gallon of clear is half the cost of another? Something is missing for sure. Also, ever hear someone complain about those car show dusters that scratch their car? I have had one for years and never had it leave a mark in my paint. But then on another classic vehicle I bought, after buffing it out I used the duster to wipe off some dust at a car show. It scratched the hell out of the hood. That vehicle has a soft clear, where my 32 doesn't. Not all clears are created equal. And that is in every paint line by every paint company.

Glenn

 

Lots and lots of great information here. Nik has done well explaining several different things. I would caution only one thing though, when he is giving his air pressures both at the gun and at the nozzle, that is for his gun. Not all guns are the same. Sata's are air whores as we all know, Iwata's not as much. My LPH400 only wants 16-18#'s at the gun, but my RP 1.2 wants 32#.

Revolver is right about arguments on painting. There are so many different ways, as long as in the end the job looks good, then they are all right. The one thing of his comment I question is about cranking air pressure at the wall. With my trigger pulled on my gun, I then adjust the regulator at the wall to what I want at the gun. This way I have even and consistent air pressure all the time. Have any of you ever been painting and then halfway down the length of the car the air pressure drops? That is because the compressor is running out of air and the wall regulator is full open. If a good diaphragm wall regulator was only giving the gun what it needed then you would never feel this pressure drop happening.

I can't remember the last time I flow coated anything. I usually spray 4 coats of clear waiting proper flash times. After a bake I will wait a day or so and sand the clear with 600, then let the car sit for a week. This opens the clear and will let all the solvent escape and will stop any pinch back from happening down the road. Ever buff a car quickly after paint only to have it pinch back a week later? It takes upwards of 7-10 days for all the solvents to flash out of a paint job. Once that is done I work my way up to 3000 and then buff. I know 5000 is out now but have yet to try it.

Another thing to remember about clears, while they all may look good after a sand and polish, or out of the gun, the true test of a good clear is down the road. The cheapest crap out there can be polished up nice, what matters is how long it lasts. All clears, even all PPG clears are all so different. One of the most expensive things in the can is the UV screener. Now ask yourself why one gallon of clear is half the cost of another? Something is missing for sure. Also, ever hear someone complain about those car show dusters that scratch their car? I have had one for years and never had it leave a mark in my paint. But then on another classic vehicle I bought, after buffing it out I used the duster to wipe off some dust at a car show. It scratched the hell out of the hood. That vehicle has a soft clear, where my 32 doesn't. Not all clears are created equal. And that is in every paint line by every paint company.

Glenn

I have been painting for 33 years, and I have tried many methods of regulating air pressure, and I still rather have maximum possible pressure at my gun, and regulate it with the gun mounted, or integral, gauge knob.

Regulating it at the wall still has the negative effects of pressure drop and increase, depending on the compressor load or build up, because the pressure the regulator on the wall is set at, is directly connected to the amount of pressure being fed into it.

If you have 100psi entering that regulator, and turn the dial/knob to set it at 30lbs exiting it to your gun,...if the pressure builds to 150lbs entering the regulator,...that adjustment would need to be dialed back to keep it at 30lbs exiting.

I rather have that control at my finger tips, at the gun,..then have to go to the wall and adjust there.

Not to mention, often while spraying a vehicle, or a bumper on a stand, you need to close the fan to get into a tight spot, so you also need to lower the air pressure when you close that fan, or the previously set air pressure will be way too high. I don't want to have to continually go back and forth to the regulator on the wall for that.