Car touch up paint process suggestions

[skeer]

So here's something that I've never heard or read anywhere but is gonna be obvious to most of ya'll. Waiting for 'flash off' or, initial drying is important right? Don't wanna put another coat on top of aerosols that aren't evaporated yet. Waiting too long is almost as bad, I did not know this. I've painted tons of stuff over the last 30 years.. admittedly never a car though. Never something I'd polish to be shiny.
I've definitely waited longer than that flash off period between coats during this recent project.

I've thrown a 2nd or 3rd coat on in the late afternoon, then either a final color coat or starting with clear the next day without a bit of sanding. <sigh>

 

[skeer]

A procedural question for anyone who is a pro and/or does this sort of stuff for a living. When it's time for the painting to start, all the prep is done and the surface is ready for spray.. Is it common for the piece to have all three layers applied in a single day?

Like primer, color and clear with the delays being flash offs only? In other words, spraying 1st coat of primer, waiting the 5-15 minutes (depending on chemical makeup and weather), applying second coat, flash, third coat, flash, first color, flash, second color, flash, third color, flash, first clear, flash, second clear, flash, etc, etc.

Doing all of that in a single "session" if you will.

 

[NFT5]

If I had somehow sanded through the clear on those areas then I should have seen the line right? Between clear and not clear, yeah?

No. I hadn't realised that you'd used spray cans for this job, but they melt into each other so there is no defined "line".

Spray cans give very poor atomisation due to the low pressure available and the product is way over-thinned so that it's even possible to spray it. That means that the solids content is very low, sometimes only around 15%. So the thickness of the coat you've just sprayed on loses 85% as it flashes. End result is that you need a lot more coats to give the kind of thickness that is needed to then be able to wet sand and buff. When painting with acrylics I will commonly put on 4 coats of clear then leave overnight, very lightly scuff/sand to level out and then spray another 4 coats. Of course, with a gun, not a spray can, but you need to put it on wet enough to flow out before those very fast thinners start drying off and the surface gets the kind of texture that you have on that bonnet.

 

[NFT5]

So here's something that I've never heard or read anywhere but is gonna be obvious to most of ya'll. Waiting for 'flash off' or, initial drying is important right? Don't wanna put another coat on top of aerosols that aren't evaporated yet. Waiting too long is almost as bad, I did not know this. I've painted tons of stuff over the last 30 years.. admittedly never a car though. Never something I'd polish to be shiny.
I've definitely waited longer than that flash off period between coats during this recent project.

I've thrown a 2nd or 3rd coat on in the late afternoon, then either a final color coat or starting with clear the next day without a bit of sanding. <sigh>

Yes, flash off time is very, very important. even more so when using high solvent content paints like those in spray cans where the solvent also flashes very quickly. I mentioned before that acrylic paints (you call them lacquer) actually melt together, coat to coat, so it's not really necessary to sand if the time from the previous coat application hasn't been that long (like the afternoon before).

A procedural question for anyone who is a pro and/or does this sort of stuff for a living. When it's time for the painting to start, all the prep is done and the surface is ready for spray.. Is it common for the piece to have all three layers applied in a single day?

Like primer, color and clear with the delays being flash offs only? In other words, spraying 1st coat of primer, waiting the 5-15 minutes (depending on chemical makeup and weather), applying second coat, flash, third coat, flash, first color, flash, second color, flash, third color, flash, first clear, flash, second clear, flash, etc, etc.

Doing all of that in a single "session" if you will.

Sure. I do a lot of small jobs - single panels, bars etc. and I don't want one job holding up the booth with multiple visits, nor do I have the time for multiple masking sessions. So I will often take a job in, mask and then prime, base and clear in the one session. Over the last few years the paint companies have been developing products to speed this up even more. With wipe-on sealers and UV cured primers it is possible to paint a full panel primer/base/clear in 30 minutes. Another 15-20 minutes of bake time and the car is out of the booth in less than an hour, start to finish. I don't have a heated booth, nor do I use the UV primers, but 3 jobs a day, through the booth is not that difficult.

 

[K13]

A procedural question for anyone who is a pro and/or does this sort of stuff for a living. When it's time for the painting to start, all the prep is done and the surface is ready for spray.. Is it common for the piece to have all three layers applied in a single day?

Like primer, color and clear with the delays being flash offs only? In other words, spraying 1st coat of primer, waiting the 5-15 minutes (depending on chemical makeup and weather), applying second coat, flash, third coat, flash, first color, flash, second color, flash, third color, flash, first clear, flash, second clear, flash, etc, etc.

Doing all of that in a single "session" if you will.

Unless it is a wet on wet sealer then no primer is not usually sprayed in the same continuous session as the base coat and clear. Especially multiple coats. In bigger shops primer can have it's own area and staff doing the work. All the rest would be sprayed back to back just waiting on flash coats.

 

[Metal-Marc]

Like primer, color and clear with the delays being flash offs only? In other words, spraying 1st coat of primer, waiting the 5-15 minutes (depending on chemical makeup and weather), applying second coat, flash, third coat, flash, first color, flash, second color, flash, third color, flash, first clear, flash, second clear, flash, etc, etc.

It's all written on the can, wether it's a rattle can or a gallon. Flash time, recoat, etc.

All paint companies have similar but different instructions. I read them and stick with them.

 

[Hank11]

It's all written on the can, wether it's a rattle can or a gallon. Flash time, recoat, etc.

All paint companies have similar but different instructions. I read them and stick with them.

This.