Another paint question....or two

[Greg L.]

Re: Another paint question....or two

The body materials that I have used have been all Evercoat products and the primer is Dupont Lacquer.

The main body work was done about a year ago and the last coat of primer was applied a few months ago. I just find lacquer primer easier to work with and it's what was originaly used so I thought it would be the way to go again...hope I was right.

The last grit that I used on it was 220(I should probably go finer,right?)and if I spray on a nice thin coat of primer it looks really good with no scratches so I'm not sure if scratch swelling will be an issue, also because of the fact that I'm so slow with body work that everything is well stabilized before it actually gets paint.

[Chuck S.]

So...uh...

How long does it take a young guy on the clock to "take it all off"? Er, to SAND it all off, I mean. It takes me weeks...but then I'm old, tired, and retired, and don't do anything I don't feel like doing. (Yep, had one of those "dues paying" screwups.)

[Chuck R.]

Re: Well S. Man it's like this

I was part of a family owned body shop that was started just as I was heading into high school.

As my Brother Inlaw (more like outlaw!)and his brother were the auto body wizards, and my Dad the finance man, that put me at the bottom of the family food chain!

You could say that I learned the business from the bottom up Yep the crap didn't fall too too far away from my professional tree if you get my meaning!!

Picture it, a young hormone exploding teen being told that he had to sand and mask cars AND clean up paint booths on Saturday nights.

I tell ya Chuck, the paint was oh let's say rather aggressivley removed from more than a few of those now classic autos

Chuckster

[Dick W.]

Re: Another paint question....or two

Prior to painting I would spray a coat of DuPont sealer to help prevent sand scratch and body repair swelling. I am not familiar with DuPont's products any more and cannot suggest a product #. The way paint's are changing it is hard to stay up with the latest and greatest. My salvation is PPG's area rep is a good friend. He is the reason that I switched from DuPont to PPG. At one time DuPont had the premier rep in my area. Both are good products.

[Chuck S.]

So You Think Hell Is...

Suffering endless pain and agony in a lake of burning sulfur?

My personal vision of hell is spending eternity being compelled to "take it all off" a sea of Surburbans, freshly primered with multiple coats of fully cured and aged catalyzed urethane primer, in a parking lot as far as the eye can see in any direction. Oh, yeah, the hours are 24/7, with no breaks for breakfast, lunch, dinner, or water, and the parking lot is located under the Texas sun, where the temperature is always 100 plus deg with 100 percent relative humidity. There is no protective clothing, sunglasses, sunscreen, or cold water. And, your every move is also closely supervised...if you "dog off" for half a second, a Taser is immediately applied to your backside. Ouch!

Whew...Having said all that, I think I should work more diligently on my few remaining sins.

[Tracy C.]

Final sand should be wet with at least 400 grit...

Especially with lacquer primer. It may look good now with 220, but the sand scratches will eventually swell. I like to wet sand as it prolongs paper life. (400 grit loads quickly)

Before you start sanding, fog a light coat of primer of a different color over the car to use as a visual indicator. When the fog coat is sanded off, you're about done...time to move on to a new panel.

tc

[Greg L.]

Re: Final sand should be wet with at least 400 gri

Thanks for that tip Tracy. Does it really matter what color the final primer coat is. Right now it is red oxide.

[Tracy C.]

Re: Final sand should be wet with at least 400 gri

Greg,

I think Red Oxide was used by the General. (John or Michael can verify) However, most modern day paint shops use grey for light color finish coats.

Your selection really hinges on what paint system you will finish up with. Base/Clear finishes use a pretty thin color coat and primer color should be close to the finish color. (Red Oxide may alter the finish color charactistic of a light color as might grey lighten a darker color)

If shooting single stage enamel, polyurethane or lacquer, primer color will be less of a factor. Suggest you talk to your paint jobber about a professional recommendation.

tc

[Stephen W.]

Re: Final sand should be wet with at least 400 gri

Okay folks I've read through most all of this thread and I would like to share my years of hands on in the dust of the body shop and at the R&D center for R&M Paints in Whitehouse Ohio. As a paint rep you get to see everybodys complaints and problems and my years of service was before the dawn of BC/CC through to the years when I was removing factory pack lacquer off the jobbers shelves because shops were not using it anymore.
The metalic is for the most part alumninum that is ground to different sizes. They experimented with "chopping" it for a sharper effect. They experimented with ground glass too but fortunately for the painters out there they didn't use too much of it. The new "flake" that adds brilliance is Mica. Translucent it passes light through it so in effect "it" lights up and its a lot cheaper than "mother of pearl".
Sand scratch swelling... This is something I spend years trying to educate body shops on. You cannot have a sand scratch swell unless there is a void in it. The reason they show up in final finishes is because the solvents are richer and reflow the dry undercoats causing them to sink into the void that was always there. You now have a 220 grit scratch looking like a 36 grit scratch. The biggest issue I had with shops was their use of cheap fast drying thinners in their primers. They dried so fast they would bridge over the void (scratch) instead of filling. The shop would go all through the steps of primer only to see a disaster when they applied a wet topcoat. Most beginners apply the primers too dry causing the same effect as cheap thinner.I got the call cause they blamed my paint. Cure? mix per label directions. Clean surfaces, properly matched thinners for temp ranges and products. DO NOT FORCE DRY.
proper dry times , temperatures , air flow.
.
Top coats... DO NOT load up a real heavy wet coat of color to "sink" the metalics. You just made an unstable paint finish. Dont spray a dry color to make the metalics stand up... you just made an unstable and blotchy finish. Spray a propery mixed color coat with the right temp range thinner and complete even passes. If you need a richer color that will retain a high gloss reduce you color with a slow drying thinner ( inside jams ect) and maybe add some retarder for hot days. Build your color till hiding and go three more to be sure you have enough to buff ( lacquer). Give sufficiant dry times and use some retarder in the last coat(s) to keep the surface open to breath and lay down.

BC/CC There has been a lot of good posts about this for trying to "make" it look like lacquer. Adding amall amounts of flatener ( talc powder in solution)... will produce a more satin finish for jams.
Don't ever try to use a true base color alone... It will not work.
Best advice here is to talk to your jobber and find out when the paint rep will be in town. He can put you in touch with the guys in the R&D center. Those guys love to talk paint and most will be glad to help.

I hear some say lacquer doesn't shine...
The amount of "shine" is simply a matter of how much light is reflected back to our eyes. Primer shines when its smooth and wet. If the finish had peal or is wavey there will not be as much light reflected to our eyes so there is less shine. Cut the surface glass smooth and not all the light is uniformly returned to our eyes and you have a very shiny finish. The 3 mils of clear on a bc/cc is what we detect on the bc/cc vs lacquer where you have the binders and clears mixed with pigments. BC is ALL high solids with agents to "FIX" the metalic and color so the application of the clear will not move it. Yes they do add flateners to base colors but that is done to correct for "flip/flop" effect. This is when a shop paints a door and it looks great from one angle but look too bright from the other.

With the far superior undercoats ( primers) and use of sealers we should have a very durable long lasting lacquer finish. It will always be hsrder & more brittle that the urathane clears so it will chip. Apply it too heavy and it will crack very easy too. Do it correctly and it will last for years and be original.

Hope this helps.

[Dick W.]

Re: Final sand should be wet with at least 400 gri

Steve a very good post. Lots of good points. Lots of things that I knew and forgot, quite a few things that I learned. Have not picked up a spray gun in seven or eight years. And with the way my lungs are, I will never again. Two words that need to be emphasized are RESPIRATORY PROTECTION. No, paint did not cause my problems, but it sure did not help either.

[Stephen W.]

Re: Final sand should be wet with at least 400 gri

Dick... I had several friends that found out the hard way about the bad stuff in paints and the introduction of hardeners was a new ballgame. I worked when they still had all the great lead pigments that made the reds so bright and beautiful. As I'm sure you know I still have all that lead in my system and will till I die.

As for our bc/cc paints and all refinish products... Protect yourself... Not just your nose! Your skin breaths it in too! Your eyes take it directly into your body. Buy the gloves and painters suit ( less dust in your paint too)
Use a full face mask if you cannot get a positive fresh air system. Only stay in the paint area as long as necessary and get out to fresh air.

[Tracy C.]

Thanks Steve...great post ! *NM*

[Dennis C.]

Re: Thanks Steve...great post ! *NM*

[Stephen W.]

Re: Thanks Steve...great post !

Glad I could contribute. Sorry for the spelling erros I should have proof read the post before posting.
I wanted to say the smoother finish is the more light is reflected back to our eyes so the greater the shine.
Very often the paint companies will have clinics or demos set up at local shops. Talk to your local jobbers and see if they have any scheduled or find out where they will be having the trade shows. There is a lot to be gained by getting the paint reps phone number. Back in 1984 I had a customer request a formula for a bright yellow that was used on a Corvette for a show. The color was not offered for production but my company had the formula because we supplied the paint to GM. The car was painted by Malcolm Konner Chevrolet in Paramus N.J. I could never understand why anyone would do a color change on a brand new Corvette...., But I helped him do it.