What next?

B

BFLIT

I am getting close to choosing a final coat color paint for my restoration project. I know nothing about the different options. I hope I can get some info from this forum. I am painting the car in pieces, that is I have all body parts off the frame, it is completely stripped, no chrome, no glass, nothing but metal to paint. I have cleaned (power washed and degreaser), sandblasted, sanded with 80 grit, applied 2 coats epoxy primer, did body work with filler, applied 3 coats poly fill primer, block sanded, more coats of poly fill as needed, block sanded again and then applied 2 coats of epoxy to seal everything up. I have also been wiping with water born W&G remover every time before spraying any paint. I have religiously kept to all flash times, I have not rushed through any of the primering or cleaning. I have used all SPI products up to this point. By the time I get to putting on final color coat some of the pieces will have been sitting that way for close to a year. I know I will need to scuff the primer before I paint but do you think it is a good idea to spray another coat of epoxy just before I final coat? Which is better, mechanical bond or chemical bond?

I also need to know about the different kinds of paint. What is the difference between acrylic enamel, acrylic lacquer and acrylic urethane? I know urethane is the most popular paint today but I am wondering what makes it so good? Is it available in a single stage? I want the car to be as close to factory original as possible but that is not a deal breaker. I am leaning toward a single stage solid color because I think it would give the car a more factory original look. I’m not after a deep, deep shine but would like something that will last for 10 – 20 years. It will not be sitting out in the sun for long periods of time.

I have heard some say that base coat / clear coat is actually easier for first time painters. I find that hard to believe. My thought is the more time I have a paint gun in my hand the more time I have to mess something up. However, if I am able to buy a small amount of bc/cc I may do some practice to see how it goes.

One other question, not so much about paint but more about the process. Would it be better to final paint all parts off the car and then try to reassemble it CAREFULLY so I don’t nick any thing? Realistically I don’t see how I can do that even though I will have a helper. Or could I paint parts off the car reassemble and then do another final final coat. I also know at some point I’m going to need to cut and buff. I assume it would be best to do that after car is put back together.
 
BFLIT;33948 said:
...I know I will need to scuff the primer before I paint but do you think it is a good idea to spray another coat of epoxy just before I final coat? Which is better, mechanical bond or chemical bond?
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There's a lot in your post, so I want to snip it up and briefly answer your questions! Yes, you need to spray one coat of epoxy on top of your sanded, cured epoxy to get adhesion. The science of adhesion is complicated; there are also dispersive and diffusive adhesion to consider. What is best is to get more than one kind of adhesion into the mix, to "stack the deck" and make sure what you put on sticks tightly.

I also need to know about the different kinds of paint. What is the difference between acrylic enamel, acrylic lacquer and acrylic urethane?
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I'm going to have to let someone else cover this, but essentially the differences have to do with whether the material forms crosslinked molecular bonds, how it accomplishes this, and how well it does it. True polyurethane is best, but it is a term that has been misused (not by SPI of course). Next best is acrylic urethane, and the rest you shouldn't worry about using.

I know urethane is the most popular paint today but I am wondering what makes it so good? Is it available in a single stage? I want the car to be as close to factory original as possible but that is not a deal breaker. I am leaning toward a single stage solid color because I think it would give the car a more factory original look. I’m not after a deep, deep shine but would like something that will last for 10 – 20 years. It will not be sitting out in the sun for long periods of time.
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Yes, single stage (SS) urethane is very popular and a good choice. It's best because it forms the largest, toughest molecules due to its chemistry and isocyanate activator. I should add that the same goes for urethane clear. It's generally accepted that in many cases, clear coat will protect the color longer, because pigments are not exposed to weather and UV the way they are in single stage. The ultimate in durability might be a single stage urethane followed by urethane clear.

I have heard some say that base coat / clear coat is actually easier for first time painters. I find that hard to believe. My thought is the more time I have a paint gun in my hand the more time I have to mess something up. However, if I am able to buy a small amount of bc/cc I may do some practice to see how it goes.
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It's easier because it dries quickly so mistakes can be repaired in a timely fashion. It is also generally more tolerant of small amounts of contamination, urethanes are not so tolerant and will fisheye easier.

One other question, not so much about paint but more about the process. Would it be better to final paint all parts off the car and then try to reassemble it CAREFULLY so I don’t nick any thing? Realistically I don’t see how I can do that even though I will have a helper. Or could I paint parts off the car reassemble and then do another final final coat. I also know at some point I’m going to need to cut and buff. I assume it would be best to do that after car is put back together.
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Painting apart eliminates problems associated with overspray in jambs and poor coverage in inaccessible areas. It takes a high degree of skill to do an overall while simultaneously painting the jambs. So, especially with a solid color that will touch up very well, it's usually worth the risk to paint in pieces, but you have to pre-fit all parts and document shims, etc. There are many tricks to this that can help reassembly.
 
It sounds like you have done all of your blocking with polyester primer. If I were you, I would guide coat the 2 coats of epoxy that are currently on the vehicle and block it out again. This way you're making sure you didn't miss anything and you're scuffing for a fresh coat of epoxy at the same time.
 
Just wanted to redouble crashes bit on assembling the whole car and disassembling before laying any color. Panel figment can be a real pita and I actually have a door I have to touch back up from where I boogered it up getting it and the fender lined up. Strums recommendation of guide coat is also an excellent one and a good cheap one I learned from jimc on here was to use dykem. Works wonders and you may even find some fine texture you weren't aware of. I may go overboard but I even guidecoat my last pass with the interface pad just to be safe.
 
This is why I like this forum so much. I would have never thought of fitting the doors, hood, front fenders and trunk before painting. Thanks for pointing that out. That makes a lot of sense. I am replacing all the body mounting pads so it is going to sit a little different on the frame than it did. Even though it is built like a tank (1948 Pontiac) there will be some give and take. Fitting parts before paint will be much easier. Thanks again.
 
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