jhdeval
Well-Known Member
lol I will try not to tell em.
Just painted the engine bay
- Thread starter jhdeval
- Start date
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DaveBonds
Garage Trash
Shop Line is very similar to PPG Omni, with higher solids.
All of PPGs formulas have a tendency to run a bit dry on a dry/ sanded panel.
I prep everything with 600 to help basecoat lay out and I use a tac cloth between base color coats to eliminate dust buildup. If I see something high that is trapped under the surface of the color layer, I'll nib it with 1000 dry after letting it sit 20 min, tac cloth it off and hit it one last time with base.
I'm not much of a PPG fan for my own cars. I use Glasurit, because it's extremely high solids on my own cars, but my boss buys PPG from the paint shop and I use it on everything we do with success.
What I've found works fantastic with their clear lines is to follow the formula, exactly.
We use Concept clears and I have used the Shop Line stuff as well. It usually calls for 4:1:1 clear:reducer:catalyst, but check yours to be sure.
I've used everything and have my preferences. I like how DuPont and Nason handle, I like the final finish of Glasurit looking wet after a year with a single color sand and buff with zero die-back/ haze/ shrinking and I like the price of Shop Line.
So, I use all kinds of stuff, depending on how important the finish is.
You should be able to get paint to lay down flat, even on a scotch-brite prepped original paint job that only needs clear to complete panel work for something like collision repair on the other end of the panel.
So I know any amount of sanding within 400-800 should be fine and won't show sand scratch swelling, once the paint has shrunk after all of the solvents have evaporated. It takes at least 6 months for that to happen, so don't wax it for at least that long. cut and buff all you want, but do not wax it until it's hit 6 months.
As for your panel pattern;
It looks like you've got ok coverage, but don't even worry about spray pattern overlap on basecoat. Nothing matters on color/ base, except color coverage and how even the metallics lay out. I usually back the gun off a bit (10"-12") and do medium to light coats on my metallics, with more coats and tac cloth between coats, after each has a 10 minute flash dry. This helps disperse the metallics more evenly.
As for your clear, it looks like it's beading, even with good pattern overlap. You want to shoot for 2/3 overlap. 1/2 or 50/50 overlap is a little too dry, but honestly, the first coat of clear that I lay down looks just like what you have, because it helps me prevent runs and sags. The suggested 45-55 static is perfect. That usually gives you about 25-30 while spraying. Higher end on that scale with high solids paints, like clearcoat.
I leave the first coat for 30 minutes and come back with a 2nd, medium/ wet coat and it grabs the dry coat nicely and lays out, without wanting to pull the paint down, because the stuff underneath has more surface tension and doesn't want to lose it's place a bunch with the 2nd coat.
I usually put 3 coats on horizontal areas and 2 on vertical panels, because horizontals get hammered by the sun and 3 coats lay out flatter than 2 on horizontal panels, helping my color sanding.
One thing that I've switched over to, with color sanding is using Kovax D/A sand paper with the 3M soft backing pad in 1200 and 1500 grit. This stuff is dry sand, which I didn't want to wrap my head around when it came to color sanding, but it's so nice, because it doesn't leave slop all over the panel and you don't have to use a squeedgee block to dry it and check your orange peel level. Whatever hasn't been sanded is still glossy and it's right in front of your face, while you sand, so there is no depth guess work.
It's also about half the price of the 3M Trizact, so I don't see any point in going back to that line and doing any wet sanding for color. Block sanding by hand gouges, each time the block reciprocates and it's difficult to get it to look even.
When you use the sander for color sanding, just be sure to wipe the panel with a microfiber, before passing over it a 2nd time and check the paper with the cloth as well, as it removes any dust it takes out and you don't want that dust leaving odd patterns in the clear as you sand.
If I were in your position, I'd remove that wiring and do as much small removal as possible. When I did the bay in the Scamp, I just disconnected the bulkheads from the main on the firewall and popped it through, then masked the hole. I pulled the master cylinder away from the firewall, but I left it connected to the lines and bagged it.
If you spend a few hours in preliminary removal, it makes a big difference in the final product.
When you shoot the body, go around on the small, awkward areas first, like the wheel lips, headlamp/ grille bucket area, jambs, etc. so they look glossy, before hitting the main surfaces. This helps prevent sagging and runs at the ends of the panels, due to dry oversights. For example, if you paint the fender nice and glossy and forget to do the wheel lip, it's very likely to sag or run right at the edge of the panel break, because the paint no longer has anywhere to flow. Check your gloss with a small flashlight in questionable areas.
Sometimes, if you get a sag in an odd area, you can chase it down with more paint until it's at the very end of the panel, where it's easier to sand out later.
There is another method I use that utilizes very low pressure and gets excellent gloss that I do on smaller things, like door jabs, in engine bays, etc. It requires a slower pace and more passes/ stripes made with the gun, because less material is being laid down. It also requires closer distance and less fan, but I gain a lot of control by doing this in my small areas and on small parts like bike tanks. I turn the gun down to about 30psi static and see about 15psi spraying, but I limit the trigger to about 1/3 distance. I used to do this when I would do touch ups at dealership lots on bumper covers. It keeps mess down and works on small square footage areas that don't lock up before finishing the spray out.
All of PPGs formulas have a tendency to run a bit dry on a dry/ sanded panel.
I prep everything with 600 to help basecoat lay out and I use a tac cloth between base color coats to eliminate dust buildup. If I see something high that is trapped under the surface of the color layer, I'll nib it with 1000 dry after letting it sit 20 min, tac cloth it off and hit it one last time with base.
I'm not much of a PPG fan for my own cars. I use Glasurit, because it's extremely high solids on my own cars, but my boss buys PPG from the paint shop and I use it on everything we do with success.
What I've found works fantastic with their clear lines is to follow the formula, exactly.
We use Concept clears and I have used the Shop Line stuff as well. It usually calls for 4:1:1 clear:reducer:catalyst, but check yours to be sure.
I've used everything and have my preferences. I like how DuPont and Nason handle, I like the final finish of Glasurit looking wet after a year with a single color sand and buff with zero die-back/ haze/ shrinking and I like the price of Shop Line.
So, I use all kinds of stuff, depending on how important the finish is.
You should be able to get paint to lay down flat, even on a scotch-brite prepped original paint job that only needs clear to complete panel work for something like collision repair on the other end of the panel.
So I know any amount of sanding within 400-800 should be fine and won't show sand scratch swelling, once the paint has shrunk after all of the solvents have evaporated. It takes at least 6 months for that to happen, so don't wax it for at least that long. cut and buff all you want, but do not wax it until it's hit 6 months.
As for your panel pattern;
It looks like you've got ok coverage, but don't even worry about spray pattern overlap on basecoat. Nothing matters on color/ base, except color coverage and how even the metallics lay out. I usually back the gun off a bit (10"-12") and do medium to light coats on my metallics, with more coats and tac cloth between coats, after each has a 10 minute flash dry. This helps disperse the metallics more evenly.
As for your clear, it looks like it's beading, even with good pattern overlap. You want to shoot for 2/3 overlap. 1/2 or 50/50 overlap is a little too dry, but honestly, the first coat of clear that I lay down looks just like what you have, because it helps me prevent runs and sags. The suggested 45-55 static is perfect. That usually gives you about 25-30 while spraying. Higher end on that scale with high solids paints, like clearcoat.
I leave the first coat for 30 minutes and come back with a 2nd, medium/ wet coat and it grabs the dry coat nicely and lays out, without wanting to pull the paint down, because the stuff underneath has more surface tension and doesn't want to lose it's place a bunch with the 2nd coat.
I usually put 3 coats on horizontal areas and 2 on vertical panels, because horizontals get hammered by the sun and 3 coats lay out flatter than 2 on horizontal panels, helping my color sanding.
One thing that I've switched over to, with color sanding is using Kovax D/A sand paper with the 3M soft backing pad in 1200 and 1500 grit. This stuff is dry sand, which I didn't want to wrap my head around when it came to color sanding, but it's so nice, because it doesn't leave slop all over the panel and you don't have to use a squeedgee block to dry it and check your orange peel level. Whatever hasn't been sanded is still glossy and it's right in front of your face, while you sand, so there is no depth guess work.
It's also about half the price of the 3M Trizact, so I don't see any point in going back to that line and doing any wet sanding for color. Block sanding by hand gouges, each time the block reciprocates and it's difficult to get it to look even.
When you use the sander for color sanding, just be sure to wipe the panel with a microfiber, before passing over it a 2nd time and check the paper with the cloth as well, as it removes any dust it takes out and you don't want that dust leaving odd patterns in the clear as you sand.
If I were in your position, I'd remove that wiring and do as much small removal as possible. When I did the bay in the Scamp, I just disconnected the bulkheads from the main on the firewall and popped it through, then masked the hole. I pulled the master cylinder away from the firewall, but I left it connected to the lines and bagged it.
If you spend a few hours in preliminary removal, it makes a big difference in the final product.
When you shoot the body, go around on the small, awkward areas first, like the wheel lips, headlamp/ grille bucket area, jambs, etc. so they look glossy, before hitting the main surfaces. This helps prevent sagging and runs at the ends of the panels, due to dry oversights. For example, if you paint the fender nice and glossy and forget to do the wheel lip, it's very likely to sag or run right at the edge of the panel break, because the paint no longer has anywhere to flow. Check your gloss with a small flashlight in questionable areas.
Sometimes, if you get a sag in an odd area, you can chase it down with more paint until it's at the very end of the panel, where it's easier to sand out later.
There is another method I use that utilizes very low pressure and gets excellent gloss that I do on smaller things, like door jabs, in engine bays, etc. It requires a slower pace and more passes/ stripes made with the gun, because less material is being laid down. It also requires closer distance and less fan, but I gain a lot of control by doing this in my small areas and on small parts like bike tanks. I turn the gun down to about 30psi static and see about 15psi spraying, but I limit the trigger to about 1/3 distance. I used to do this when I would do touch ups at dealership lots on bumper covers. It keeps mess down and works on small square footage areas that don't lock up before finishing the spray out.
jhdeval
Well-Known Member
Awesome information thank you I will definitely use this as reference. Experience speaks volumes.
DaveBonds
Garage Trash
Here are some reference shots of what I took off and how I did the engine bay in the Scamp. I did the bottom of the hood and the hinges at the same time.
The master cylinder looks like it was taken off, but it got bagged with the engine and the lines were masked. The E brake, wiper motor, heater inlet and outlet as well as anything else that shouldn't have paint on it, like insulation clips were all masked.
That shows a picture of the components restored that went back on, including the wiring and shows that the engine was not removed during paint.
I pulled a lot of the top end of the engine and cleaned everything up in a blasting cabinet.
Flip flopped the masking and did the engine stuff. Pulled the manifolds, pulleys, PS pump and I needed a new gearbox, so I pulled the old one while I was in there prepping for paint. I also blacked out the grille areas as per the original pattern, so body color wouldn't show through the grille.
The wiring harnesses are original, but I unwrapped them, tagged branch areas with red tape to keep everything intact and replaced entire wires as needed as well as terminals with soldered ones and heat shrink tube, before hanging one end from a wire, pulling the wire tense and re-wrapping each one. I also managed to gain 4 volts acrossed the headlamp and ammeter circuits after going through everything. I media blasted the bulkhead pins and coated them with graphite paint, which is conductive and helps keep it from corroding.
The master cylinder looks like it was taken off, but it got bagged with the engine and the lines were masked. The E brake, wiper motor, heater inlet and outlet as well as anything else that shouldn't have paint on it, like insulation clips were all masked.
That shows a picture of the components restored that went back on, including the wiring and shows that the engine was not removed during paint.
I pulled a lot of the top end of the engine and cleaned everything up in a blasting cabinet.
Flip flopped the masking and did the engine stuff. Pulled the manifolds, pulleys, PS pump and I needed a new gearbox, so I pulled the old one while I was in there prepping for paint. I also blacked out the grille areas as per the original pattern, so body color wouldn't show through the grille.
The wiring harnesses are original, but I unwrapped them, tagged branch areas with red tape to keep everything intact and replaced entire wires as needed as well as terminals with soldered ones and heat shrink tube, before hanging one end from a wire, pulling the wire tense and re-wrapping each one. I also managed to gain 4 volts acrossed the headlamp and ammeter circuits after going through everything. I media blasted the bulkhead pins and coated them with graphite paint, which is conductive and helps keep it from corroding.
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