@Jaborszki Csaba you want to thin your IPA with distilled water and wipe using the two towel method before it dries. It's important to understand what the IPA actually does is it breaks the bond between contaminants and substrate and allows the contaminants to float in the puddle of IPA so long as it's wet. You need to wipe the surface dry with clean towels, if you allow it to dry the contaminants simple stick to the substrate again accomplishing nothing..pure IPA, well 90% or whatever you can get, evaporates almost instantly and is going to dry way too fast to work properly. As far as primers and sanding grits first of all both sealer and epoxy primer are not sandable. If you need to sand either of them you are either spraying too thick or the surface you are spraying needs refinement. Second epoxy might say it can be sprayed on top of 120 grit scratches but it won't fill them and they will telegraph through whatever is applied over it. 320 grit seems to be a very good universal scratch for epoxy to adhere to and you won't have to sand it. Apply only one coat of epoxy. Same with 2k sealer just one coat. A wet coat but nothing crazy. Your epoxy and sealer should go on wet and dry slick for basecoat to look good. If you are applying polyester putty it prefers 80 grit sand scratches. You sand it with 80 grit and follow with glazing putty which is sanded with 320 and then a coat of 2k sealer followed by basecoat. This is not complicated but you are making it very complicated I don't understand why. I have been doing this years and was taught the right way and never had a come back never had a paintjob peel or fail ever. Ever! Since you sound like a newbie I will give you some very good advice, keep everything you will be using on the job sand paper scuff pads microfiber towels keep everything from when it's brand new clean! Wear gloves whenever you touch something let's take sand paper for example. It should never touch the ground nor should you sand with bare hands. Tape is another one don't lay it on the ground. It's very easy to spread contaminants into your substrate and will lead to problems thT are difficult to pin down. Clean clean clean you can never be too clean with this line of work.

@Joseph Hansen yeah you want to protect metal with epoxy first but epoxy is usually what we use on resto work when it might be some time before anything else is done. Epoxy primer needs a lot of cure time unless you cure it with UV. just straight 2k epoxy sprayed onto metal can take days to weeks to cure and die back. For production work we ain't got that kind of time and in those situations (most of the time) body filler is applied directly to PREPARED bare sheet metal. By prepared I mean it's been cleaned with a solution scrubbed with red scotchbright cleaned thoroughly dried and immediately primed blocked and sealed. We use sealer for protection. It seals moisture just fine the difference is that epoxy bonds with metal really well. Self etching primer works just as good as epoxy come to think of it as far as bonding with the metal is concerned. Epoxy is only really used on bare frames which is also how it's used by the factory. They don't epoxy the whole vehicle I'm not sure if that has ever been explained or not. At the factory the frame and undercarriage get hit with epoxy then sealed and some kind of powder coating is applied. For the rest of the vehicles all the panels for example it's etching primer sealer base clear. That's also the workflow we follow at the shop. At my last shop bare metal just gets hit with sealer unless it's a large area then it's etching primer sealer or 2k filler then sealer etc etc. Body filler bonds best to clean scuffed bare metal. It's hydroscopic sure, that's why we seal it well before base coat. And no matter what you do body filler WILL ABSORB MOISTURE it's inevitable which is why in this trade you must master the hammer and dolly and get your metal work perfect. Body filler should rarely be used and only sparingly. Personally I avoid it unless it's too time consuming to get my metal work perfect. Polyester putty is my go to. I haven't used bondo In ages. And when I do it's always metal reinforced.

Raptor requires quite a bit of prep if you want it to last. Sand down whatever is there to bare metal and apply their self etching primer first is how I do it or it will peel. Also they make a gun so you can spray it I recommend that over rolling it.

@Ron Bell I am not sure raptor is designed to stick to epoxy primer. It's very specific what it will or won't adhere to. As raptor makes its own line of primers I would personally stick with all raptor products if you want the stuff to adhere well and last. I think if done right you'll get 10 or more years out of it. I do recall on reddit a guy having a hard time with it in high humidity (he lives in Texas) and I think what he figured out was when you spray it the temps have to be moderate (under 90 degrees) and the humidity has to be pretty low maybe 30% or lower. He had his peel several times after good prep and through trial and error figured out that it's very sensitive to temps and humidity when applying also worth thinking about is where you will keep the truck when it's off gassing. Your garage at home perhaps but I would keep the door open and a fan going 24/7 for a few days or you risk complications, not quite solvent pop but I do know the coating doesn't like to stick as well as you would expect. It's expensive and time consuming to have to redo it, worth the extra time in prep. Also before and after you abrade the substrate I would clean thoroughly with ipa (90% thinned with distilled water) and a good wax and grease remover. Be absolutely sure both have evaporated before shooting. I don't think you run the risk of solvent pop by running fans so I might suggest considering running some when you apply the coating. You more or less want to force cure the product as quickly as possible before any moisture gets a chance to become a problem. Good luck.

@Aaron Jokela the best paint store nearby (South San Jose) is finish master and from memory they have really gone downhill the last 5 years or so. But I'll give them a shot. They do carry PPG. I'm not sure about HOK there is a supplier that carries it called arellanos I suppose I will try them Tuesday. . Any advice on the actual bodywork any process to follow? Thinking of using slick sand followed by poly2k and lots of blocking. The car itself the body seems to have lots of curved surfaces and it seems difficult to achieve a really perfect body. Whatever shop painted it before (it was in a wreck) didn't seem to do a very thorough job. But it is an old car, the owner seems willing to spend more than the car is really worth to make it look good. If it were up to me I would shoot a good single state and call it a day. As for clears I know you like pro air fast and slow but how durable are they and how well do they stand up to washes and typical day to day use? The owner drives his car a lot it seems. I really wanted to get him a good clear with some self healing ability along with gloss retention that I won't have to kill myself getting it to lay out. Really not wanting to have to cut and buff if i can avoid it. So, basically a unicorn clear I guess. Owner willing to spend a grand on clear so that should help at least. What do you think? If this were your job how would you go about it? Appreciate the insight.

@Randy Sizemore you don't need to use air lines that big for your spray gun, 3/8 inner diameter is plenty. Reduce at the filter or regulator. If using HVLP regulate at the wall if using conventional or HTE regulate at the gun.

@Esa Harvela chatgpt is retarded half the time I take what it says into consideration but never is it the one making final decisions. If you ask it the same question every day it will give a different answer every time

Use compressed air to blow off as much as you can get an angle grinder with a paint eating wheel looks like a mesh fabric sort of remove the rest you are going to need to prime block seal base clear to make it look good do not bother sanding what's there down you'll be sanding down to metal anyway the angle grinder is much faster