Brett Jenkins

I'm going to give painting a bumper a try. Worse comes to worse, I can just strip it again and send it to a painter, but I'd still like to give it a try.

What primer should I use? Is there any kind I shouldn't use to avoid adhesion problems between primer and base?

I have a quart of black DuPont chromabase. What do I use to thin or reduce it down and to what ratio?

What kind of flex additive do I use and what other, if any, additives do I use?

How many coats?
Do I sand in between?
Do I sand before/after clear coat?

Any other suggestions, tips, caveats?

Thanks in advance.

BBX

Brett, you might get better advice from a body shop. Not to say that their aren't some great painters here, but I would ask someone that does it for a living. (just my 2 centavos...)

Brett Jenkins

Rennlist is vast and encompassing. Good chance that someone here does do it for a living, or at least does it on the side and quite well.

Brett Jenkins

Came off the car. I was rear-ended, but the damages was mostly just paint. One small indentation to repair but nothing major. I'll need to strip it down and start from scratch.

Garth S

One tip of advice from the shop that resprayed the nose cover of my C4S was to use very little, if any, of the flex additive: reasons being that it was difficult to achieve a matching gloss level if the additive was present .... and secondly, that any future impact severe enough to bring the merits of a flex agent into play will necessitate paint repair anyway .... so why bother - so I didn't .

Brett Jenkins

I don't have clear yet. Suggestions?

soupcan

Why not stick with the same line and use Dupont ChromaClear.
I used 7900S Clear and midtemp activator, the activator is numbered for temp 7975=75F,7985=85F,7995=95F

BBX

Brett, so the bumper never actually cracked? That's great news.
If you were local, I would let you borrow my sodablaster to remove the paint safely and quickly

BBX

Since so many of you are in the painting field, what do you think about sherwin willliams auto paint? I talked to a shop and they said the sherwin stuff is replacing the ppg stuff because it's a better quality. Is this true?
What is the highest quality paint you all know of?

Garth, doesn't the flex additive also let the paint stretch with the climate change?

RyanPerrella

You know i would have the entire bumper blasted first.

This was something Brendan first suggested to me years ago and i thought it was unnecessary. But these bumpers will easily crack if not prepped properly.

I would check into having the bumper stripped with a media blaster first then you have a clean even porous base to prime then paint. If your going to do it right, you can, but there is just a bit of extra prep you may want to do with THESE bumpers.

JHowell37

For starters, factory paint doesn't crack and peel like that. You have to strip it down completely and start from scratch. If you don't it could cause problems in the future.

The plastic those bumpers are made from is the reason why so many painters hate painting plastic. It will require an adhesion promoter, and it will require flex additive. I'm not sure where people come up with ideas like "flex additive causes problem X, Y, or Z." It doesn't. Use it, you'll be happy you did.

As for the actual process and the specific chemicals you'll need, you should go to the DuPont website.
http://pc.dupont.com/dpc/en/US/html/...omasystem.html

They are the chemical engineers. They know their product. Relying on old wives tales to get it done is a surefire way to increase your frustration and cost of this project.

Look through the section on plastic repair and refinishing. All of the info you'll need in order to do this job properly is on the DuPont site.

To be honest, there's a lot of **** you'll need to buy in order to get it done, if you haven't taken on a painting project before. If you want to do it just to do it, then go for it. For just a bumper, I'd strip it, to make sure it was stripped, and then take it to someone else to paint, and make certain they are going to do it properly.

JHowell37

If it's peeling and cracking like the pic shows, it needs to be stripped. The current paint already has adhesion issues. Maybe it doesn't have to go down to raw plastic, but you'll need to remove every layer until you get to one where the entire layer is stable.

BB79, one of the primary reasons why a shop chooses one brand over another is price. When I think of SW, I think of house paint.

Personally, I like Glasurit, which is made by BASF. Now that makes me a snob in the eyes of many because Glasurit has a reputation for being expensive. I'm lucky because the wholesaler for BASF products will sell me Glasurit 55-Line for 10% less then what the DuPont wholesaler will charge me for Chromabase. And you can forget about Chroma Premier, or Spies. Both are DuPont's high end products and my wallet can't touch the prices they charge for them at the local supplier.

slate blue

By JHowell37Agree with all that.
Again, perfectly correct.

Again I used Glasurit on my car and Standox for the wife's, both are concours winning cars in their respective categories, Glasurit is the better paint, Standox is a watered down Glasurit. I would use the flex add, I had my car painted before I decided to do it, the bumpers cracked on the way home on the truck! Even when my wife smashed my car into another one of my cars in the driveway the paint didn't crack but the metallic did slightly craze. If it was a sold colour, there would have been no damage.

Greg

Tampa 928s

928TT: I seen him in action, my car is beautiful and I hammered him with every question known to man kind. He helped me touch up a Honda a few months ago same issue cracked paint on bumper and fender. Very little fan fair to repair it and paint it. One thing to remember all the products in the world are not going to help if you do not know how to paint. With a leaned hand blending a bumper is not an issue. If you follow advice your into a big project with the same results. There is no magic in this except for years of experience in the prepping and application. I screwed up my front fender over sanding, I thought I'm screwed all the work, sanding, priming etc. 928TT came in in ten minutes straighten it out you will never know it was there. I would suggest you listen and have a professional paint it for you. The blending involves a different pressure and mix to blend in and a artful hand.
Just my 2-cents worth!

Larry Velk

Some guys argue about flex, some say it is only for the installation and "flashes off" after a few weeks. I don't know for sure, but I have done several Merkurs which have our style paint - some sort of German enamel in single stage to color solids. There are miles of flex panels on Merkurs and I've used PPG flex agent in all the urethane parts. We pound these cars winter and summer - they sit outside and teenagers drive them. The flex is fine and you can't tell the flexible panels from the rest of the car - this is after many years of salt and sun. The PPG was Concept. It gives a finish very, very similar to our solid color 928's. I even painted the gas cap with flex by mistake (I had it hanging on wire with the other stuff) and it had the same color intensity as the steel without flex. Some guys flex the whole car, 'tho I'd not do that.