I'm getting ready to prime and paint my radiator support. I have sandblasted it down to bare metal, and am getting ready to refinish. I am using DuPont products, and so far I have some metal conditioner, some self-etching primer, some prime-and-seal, and a quart of black acrylic enamel. This is the first paint work I am doing so far, and I'm trying to get everything worked out. What I am planning on doing is next metal conditioning it (I know it's not really necessary with the etching primer, but I figured it was still a good idea), and then spraying the etching primer followed by the prime and seal and then topping it off with the black. This is what I was going to use for the front wheel housings and the firewall as well. Please if you have any suggestions let me know, I'm pretty new at this. Is there to be any sanding of the primers? How long between products? What pressure do I spray at with an old syphon gun? How many coats of each product? I think I know what I'm doing here, but I want to double check with you guys first.

Thanks,
Steve

Skip the metal conditioner, and go straight to the etch primer. If the metal conditioner leaves any acid on the surface, you can loose adheasion when the etch primer acid attacks it instead of the metal!
You really need to get the tech sheets or at least read the info online to get all of the questions answered. It depends on a number of things whether or not you need to sand or not. If you stay within the "window" set by the manufacture, you won't need to sand at all.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

What then should I use to clean the bare metal before the etching primer? I got a gallon of laquer thinner for cleaning guns, can I use that?

I agree, i would skip the metal condintioner unless there is surface rust forming on your panel. The etching primer is a wet on wet application. Depending on how rough the surface is from the sandblasting, you may want to go with a light coat of high build primer or any type of primer surfacer. That is a product that requires sanding in order to acheive adhesion, and fills the small imperfections from blasting as well.
if you are spraying a solid color, like black, gun pressure is not critical, but should be somewhere between 40 and 60 psi at the gun. ideally you should ask for tech sheets when you use any product. It always works better when you follow directions.

Yep these guys are right.. Get your etching primer on there and then a buildable primer to smooth things out.. Read the tech sheets.. I haven't so far seen a window over an hour so you have to be ready to spray quick.. You will have to sand your buildable prime, but everything else should flash then coat over top of it... Sounds like you have a good idea on what you are doing!! Good Luck!

A thought that might help about non sanding salers. Take a look at all the late 80 and up GM cars, trucks, and vans driving around with the paint literally flying off the vehicles because of poor primer adhesion, directly related to non sanding primer sealers. They came out with this junk to speed up assy lines.
Personally I don't think this stuff is worth it's weight in horse manure.
Put a good urethane hi build primer on, sand it with 400 grit wet paper, let it dry, tack cloth it, and then shoot it. this will keep your paint where you put it..

Red2Rider, I agree what nonsanding sealers are a waist of orange peel, but you are off on the GM pealers, they had nothing to do with any nonsanding sealer YOU or I will ever see. In fact that wasn't even the problem at ALL, but that is another post.

For shooting things like radiator supports, inner fenders, frames, control arms, etc. There is nothing like a non-sanding sealer or primer. Why in the heck would you want to sand a frame? You sand blast, etch prime (most have a 24 hour window) WITHOUT sanding, you apply an epoxy primer (most have a 24 hour window) or the primer-n-seal and then WITHOUT sanding apply your top coat, lickity split you are done. http://www.chevelles.com/forum/smile.gif

snydes, don't worry about cleaning the metal. It has been sandblasted right, unless you ate a bacon cheese burger on it, don't sweat it. I have seen etching primer sprayed on poorly washed truck frames with plenty of grease or deisel that held on fine. We are talking about an ACID ETCHING primer here. It will stick to glass without sanding, it will certainly stick to your sandblasted radiator support.



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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

So MartinSR your saying that a non sanded primed frame will resist a rock chip better or as good as a sanded final primer coat before painting.
I can't agree with that. I've seen cars that had rock chips on the fronts more severe with the nonsanding than a sanded primer. I might be somewhat old school with all the new products out there. But I stick with my routine because I know it works the first time.
As far as painting goes I think we both can agree theirs many different ways to get the jobs done. I just stick with what works for me.

Well guys, I took the plunge, my first bit of paint work! I did a little wipedown with some laquer thinner at the spots where I had to handle it, and sprayed my primers (etching and sealer). I will topcoat it tommorrow, ran out of time today. It was a learning experience, I made a bit of a mess.
The one thing I'm not real sure how best to do is how much flattener I to add to my paint to get my desired look. I guess It will be hit or miss kind of thing, see how it looks on a test piece and adjust from there.

Thanks for all the help, I made sure to check the boards to read all the latest posts before I started!

Steve

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MY PROJECTS
1967 Chevelle SS396 - Currently under construction

1970 Camaro RS Z28-
Currently thinking about it

snydes, sounds like you are on the way to a fine car. Be sure to check that window on the prime-n-seal, since you didnt' get it shot today. On the flattener, you should be able to get the mixing ratio from your jobber for the correct flatness. I have had problems with that though and end up with the test panels like you mentioned. Be sure to let it dry good so you will get a true example.

Red2rider, I mean no disrespect, there is of course many ways to do things. I was a paint rep for five years and I have seen may people "getting the job done" that were spending may too much time (time=labor costs in a shop). If you are doing this as a hobby then time only matters in the fact that we all wish we had more of it to do our hobbies!

In the examples you give where the non-sanding sealer or primer didn't hold up to rock chips as much as the sanded primer did.
There are so many different variables (as we have already agreed) that we can't say what caused one or the other to react the way it did.
One thing for sure is that the undercoat IS the most important factor in chip resistance. You need a "cush" to allow the paint to flex and rebound when it is stuck. Picture painting a cue ball and a golf ball with the same paint. Drop them both on the concrete. The cue ball will chip much more than the golf ball. The point being that the paint was able to flex more on the golf ball. The application of a non-sanding primer sealer usually gives you much less film build than an application of urethane primer that gets sanded. Therefor the urethane primer that got sanded is better protection, not so much because it was sanded, but because it is thicker and gave the cush that the paint needed.

The paint undercoat of choice for many truck fleets is an etching primer, epoxy or HS urethane primer sealer and a single stage urethane paint. No sanding between any product (sanding a pair of bottom dumps is a BIG job) and these paint jobs hold up better than just about anything you can imagine.

Now, if you want to sand a urethane painted frame before you paint, you WILL end up with a durable finish, probably even more than the "quickie" non-sanding job. BUT if you miss ANYTHING on the frame, that will be a very weak point of adheasion for the paint. That is the biggest reason for the non-sanding primer sealer, you apply it and paint it, no possiblity of missing while sanding and it gets everywhere.

To clarify, I am not a fan of sealers PERIOD. I NEVER use them in painting of exterior surfaces. They are just orange peel makers, but for chassis parts and other "non-critical" appearing parts a non sanding primer sealer is the only way to go. That's just my opinion. http://www.chevelles.com/forum/smile.gif


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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

Don't mean to be picking on anyone but Ya'll need to listen to Martin, he's dead on the money and is trying to save you tons of work. Use etch primer, followed with epoxy primer, then go with a single stage urethane and that's as bullet proof as your going to get with todays paints. If you watch the time thresholds for applications, you do not have to sand it, this is very, very, important and when done correctly this is where your going to save yourself tons of unnecessary work. Trust me if done correctly, you couldn't beat this stuff off with a jack hammer.

Correct etch or epoxy then paint.No fuss no muss.