Author Topic: painting bare metal-what do you recommend  (Read 7721 times)

seattle_Jerry

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painting bare metal-what do you recommend
« on: January 19, 2008, 14:08:29 »
I want to do spot fixing of surface rust before it becomes something worse. What do you guys use as a temporary primer? I'm not planning on sanding the whole car down til next winter at the earliest.

I spoke too soon on the mostly rust free. I found some on the underside of the trunk above the gas tank. Thats what I get for removing the gas tank.

Do rattle can primers and rustoleum really keep out the moisture?

1967 230SL Havana Brown Auto with A/C

ja17

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Re: painting bare metal-what do you recommend
« Reply #1 on: January 19, 2008, 19:32:34 »
Hello Jerry,

Regular primers will not stop moisture from getting to the metal. They are designed only as a basecoat. It will only take a week or two before rust shows up on exposed primer. Most primers condition the metal and create a good bond for finish paint. Think of them as a "sponge" very porous, to catch and hold the finish paint. The finish pain seals off the system. Aerosol paints are thinned excessively so they can spray out of a can, so they provide the least coverage and protection.

Some more advanced primers (epoxy primers, primer/sealer and commercial two stage primers) will do a better job as a sealer. But non of these are intended to be left exposed to the weather for a long period of time.

Here is one easy solution for the amatuer, you can buy some Rustoleum "Rusty Metal Primer" it is a very good bare metal primer to go over bare metal. It is easily available, inexpensive, brush on, or spay can, (brush is best). I think a quart can runs around seven or eight dollars at almost all department stores or hardware stores.  It has fish oils and a lot of other conditioners for preventing rust. It is great for floor pans, frame channels, underbody etc, Use a semi-gloss or flat black rustoleum to seal it off. The non-gloss finish will accept your finish paint color sometime in the future. You will have plenty of protection until then.  However it will need a day or two to completely dry.

Many more exotic and more expensive products are available from companies like "The Eastwood Company" check it on the web.

Joe Alexander
Blacklick, Ohio
« Last Edit: January 19, 2008, 19:33:14 by ja17 »
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

cth350

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Re: painting bare metal-what do you recommend
« Reply #2 on: January 19, 2008, 21:12:37 »
One of those "more expensive products" is POR-15. It works rather well for areas that are out of the way, like the inside of your trunk.  It's a bear to get off once it's on and it requires some sort of top coat.  Don't use it on anything you want to repaint later.    My local ATV store sells the stuff, if you need it "right now".  Otherwise, mail order is a bit less.

Be rather careful with this stuff and similar products. The thinner is rather toxic and if you spray it, special respiration equipment is necessary or else you'll paint the insides of your lungs and that is likely fatal.  If you get it on your hands, only wearing away the skin will remove it (about 2 weeks of labor).  That part I learned by doing.

-CTH

Richard Madison

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Re: painting bare metal-what do you recommend
« Reply #3 on: January 20, 2008, 04:23:45 »
Just to mention that Eastwood also has a Paint On Rust product that "cures" under high heat. Used for painting hot items like rusty exhaust systems, manifolds, and other hot pieces (after brushing the loose rust off.)

Comes in gray, and maybe black and other colors.
 
I used it on a rusty '66 Mustang exhaust...looked great and lasted until I sold the car several years later.

Richard M, New york City
1969 280 SL, Tunis Beige, Euro Model (Italy).

230slhouston

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Re: painting bare metal-what do you recommend
« Reply #4 on: January 20, 2008, 11:13:34 »
I am using POR-15 to do some undercarriage painting and my trunk. I have some rust scaling and after cleaning, I am coating it with POR-15.

I do plan to give have the car stripped and painted in about 2 years, this is an interim measure while I get the car roadworthy and drivable.

Does anyone know if the body shop will have a problem stripping the POR-15 later on?

Thanks
MB

Maistran (MB)
230sl