Metal Prepping

[Atazman]

I'm beginning to remove my paint down to the bare metal. and prep it for new paint.  Can someone who has done this tell me exactly the metal prepping material that you used (or is recommended) on (a) the aluminum doors, hood, trunk lid, and (b) the steel body?  I'm looking for the right stuff to "condition" the metal before laying down any primer.

Your input will be appreciated.

[mdsalemi]

I believe it would vary depending on the paint system you choose.

First choose your paint brand and type, and then review and purchase the appropriate materials from the same supplier to ensure compatibility and proper prep for the paint.

[Rolland]

Michael,  you are spot on.  I used to sell house paints, and while they are vastly different than automotive paints, they all have their "systems" for what they were going on (type of surface) and the correct way to prep the surface and get it ready for the top coat of paint. 

Rolland

[Atazman]

Thanks, Michael and Rolland.  Your advice is appreciated.

I got on the PPG site and found a "Wash Primer" which they recommend for both aluminum and steel.  Other than a good cleansing, no metal prepping is needed before laying down the "Wash Primer".  I have heard good things about PPG products, so I'm hopeful I can use their products exclusively.

[George Des]

Don,

I painted my 67 230sl with PPG Omni single stage polyurethane over their epoxy primer (DPLF-50) and PRIMA K36 Primer surfacer. The metal prep I prepped the aluminum and steel were also PPG Metal Prep and Aluminum prep. If you do any filler work--you undoubtely will to get seams to line up on the doors--follow the PPG instructions and apply the filler over the epoxy primer and not under it. The filler actually adheres better to the epoxy and the epoxy seals the steel or aluminum from any moisture that may be carried by the filler. Hope this helps.

George Des

[Atazman]

Thanks for the input, George.  Wish I had mine done.  Biiiiiiig job ahead.

[George Des]

Don,

This is a big job if you take on yourself like I did. Endless hours of research on different paint and prep products as well as investments in the right tools--forced air breathing equipment, MIG welder, HVLP spray set-up, etc. I did this all in my garage over a period of about 3 years after a complete disassembly and rebuild of all components including the engine. The worst part of the paint job was the stripping to bare metal and judcious use of filler in areas to get the seams to line up. I used a combination of stripping methods including a dry stripper that avoided the gooey mess of wet strippers and sanding where it made more sense.Like your car mine is an Italian model and had very little rust to deal with-- filler was only applied to build up areas around the aluminum doors to get the seams right and to cover some small areas I needed to weld in some new sheet metal. I'm sure many of the purists would find flaws in the paint job, but after color sanding and buffing, I'm more than satisfied with the job and have the satifaction of knowing what is under all those layers of paint, primer and surfacer. Will post some pictures when I get some time.

George
1967 230SL 5 speed ZF DB-050 Italian model
Owned since 1976

[stickandrudderman]

Once you get the paint off, you should apply some (any) primer just to act as a barrier to oxidation. This primer is sacrificial (you'll take it off again as you work the peice). Failure to do this is likely to lead to micro-blistering many years down the line.

[Atazman]

Thank you, George and Stick, for the guidance.  Some questions........... (1) Stick:  Does the "micro-blistering" happen with aluminum too?  I have had my hood sanded down for a few weeks now.

(2)  George:  I'm investigating the PPG Omni paint systems right now.  PPG lists which paint components meet the Bay Area Air Quality Management District (BAAQMD) VOC requirements.  Not sure where you are located, but did you have environmental restrictions as well?

I'm also contacting the BAAQMD to determine what other requirements I must meet besides the VOC limits.  Waiting for a response from them to determine if painting my car is "doable" in this highly restricted San Francisco area.  My plan is to sand the body down to bare metal (orbital sander and by hand where necessary) rather than try  blasting or paint removers.  But I'm waiting to sand down the "steel" to bare metal until I know for sure how to treat it and what products are compatible with each other.

So.............lots of planning and investigating is still ahead of me.

Thank you guys, .......and let me know if you have any other thoughts or good ideas.

[stickandrudderman]

The problem is more prevalant with steel, but is does happen on aluminium (a-loo-min-um to you who would corrupt the Queens English!) too.

[mdsalemi]

I'm also contacting the BAAQMD to determine what other requirements I must meet besides the VOC limits.  Waiting for a response from them to determine if painting my car is "doable" in this highly restricted San Francisco area.

Uh oh.  If you already contacted them you MAY have let the cat out of the bag.  If you wanted to do this yourself without a government partner, it might be too late.  If they hold you to the same standard as commercial operations, you may simply want to cut your losses now and send further work out to someone who has the [ungainly and ungodly expensive] equipment to deal with the emissions, dust recovery, etc.  Remember the old adage, 'tis easier to obtain forgiveness than permission.  My brother twisted that around to "To seek permission is to ask for denial"

In this Michigan area, which probably doesn't have nearly the standards that you do in the beautiful bay area, the paint booth equipment at my local place cost hundreds of thousands of dollars.  I think the same story exists at the Classic Center in Irvine.

Fun, challenging as it might be, present and coming laws do not make it easy for someone to do these kinds of things legally any longer, in their garage.

[graphic66]

You may be required to use "waterborne" paint. A real pain to use and it has durability issues according to my body man. In New York you will soon be required to use it, the place he works has made the switch. They dry it by blowing air on the car, not heat. You must have a completely clean area or you get dust blowing into the paint. He says there compressors are now overworked and they need to be upgraded to handle the supply needed. I don't think waterborne paint is for someone not equipped to spray it. Not like laquer or enamel that just dries with time. I am not a painter, but have been warned by my friend that soon this will be the only paint you can use and many small shops will not be able to afford the upgrade. Big brother gets bigger! 

[mdsalemi]

On a similar but related topic: today's NY Times had an article on "barbeque" pork ribs being done in the oven (oh, the heresy!) at LA's Animal Restaurant.  http://www.animalrestaurant.com/  Real chefs, as it were, would never consider ribs without smoke and flame as properly prepared.  Why does this trendy restaurant make them this way?  Because the smoke scubbers for their KITCHEN would have cost $1,000,000+ to comply with local laws!

Would you like to go green?  Throw out your grill.  Eat only raw food.

[George Des]

Don,

I'm in No. Va. I don't know what the restrictions are, and I did not ask. Like Michael siad, better to beg for fogiveness. I was able to do this in my garage after setting up a paint booth with plastic sheeting, air filters and a blower system I also had a hobby air supplied air breathing system because the Omni paint and primers I used contain the polyisocyanates hardeners that are very harmful to breathe. A normal charcoal respirator is not effective against these. I did a lot of research before I undertook this project. Len Stuart's  Autobody website was a hugh help in this regard.

George

[Atazman]

Thanks to you all for your advice and comments.  I'm still in the sanding stages, but it would appear that I will have to take the car to a professional painter when the time comes.  That is not all bad for several reasons. 

Just wanted you to know the status of my car.

[stickandrudderman]

I will have to take the car to a professional painter when the time comes

A wise move that you will not regret, unless you take it to the cheapest painter you can find.

[mdsalemi]

I'm still in the sanding stages, but it would appear that I will have to take the car to a professional painter when the time comes.

One more piece of advice, Don--while you are working on the body now, might be a good time to actually find that painter.  The good one will become your friend, and help you along in the process.  There are those that will not want your participation, and those that will work with you.  There are those that will give you advice to help you, and eventually help them, too.  So, don't wait until the car is ready for paint, start your process of finding a good painter.  My guess is the best painter for you will become very obvious after getting a few recommendations in your area and talking to them.  Best of luck and keep us informed.

[JamesL]

Would you like to go green?  Throw out your grill.  Eat only raw food.

actually, eat only raw veggies. Them thar cows are a huge source of methane.....