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ride26fast 12-13-07 11:54 PM

Steel
 
I have done my first still frame, and am now looking to paint it...i was wondering if i left any of the steel bare (no paint covering it), can i just put the clear coat on top and it will be fine? or will it rust..?

ride26fast 12-13-07 11:55 PM

haha.. typed to fast... i meant: "my first STEEL frame"

thanks

Falanx 12-14-07 05:03 AM

I think this has come up before...

Clearcoats tend to be a little porous. It's a combination of their polymer chemistry and the fact you're not going to be putting down two coats of primer, three coats of paint and then your lacquer layer...

If you can give the frame a damned good going over with fine emery cloths and find yourself some oxalic acid to wash the frame in (you can buy it to make up with water from some hardware shops - although I'm not sure which ones to recommend on your side of the pond), then that's the best possible start you can give raw steel for a clearcoat.

Then:

PUT LOTS OF LACQUER ON. In as many fine layers as you can ;-)


But the short answer is, it's far more likely to discolour and rust with just clearcoat than it is with primer and paint as well..

velonomad 12-14-07 06:16 AM

I didn't have any longterm success with clear coat over bare steel. best I got was about a year before it began staining under the clear coat. Finally I gave up on making repairs and did a proper paint and clearcoat. I used Audi paint color " Aluminum Silver" ( code LY7M) which looks a lot like clear coated bare aluminum. If you were to squint your eyes while drunk you might think it is clear coated steel.

Oxalic acid here in the colonies is better known as "wood bleach".

Falanx 12-14-07 02:08 PM

Is the stuff retailed as wood bleach pure oxalic? Or does it have some other stuff mixed in there? I'd recommend actually buying it from a schools/colleges/universities/research chemical supplies wholesaler, but you're gonna get stiffed for the cost of it.

The reason I'm suggesting oxalic is because you get a degree of passivation of the steel, without generating black iron oxide (magnetite), which is anodic to the steel underneath and while it protects the steel, it does so only until it's scratched - then it accelerates the corrosion.

It's the only oxidising reagent that's reasonably safe to use, cheap and doesn't grossly alter the observed colour fo the steel.

ride26fast 12-14-07 03:49 PM

haha, guess it is going to be all paint....dont want to take any chances with my first :)

Falanx 12-14-07 03:50 PM

Good idea :-)

velonomad 12-19-07 03:12 PM

Quote:

Originally Posted by Falanx (Post 5809605)
Is the stuff retailed as wood bleach pure oxalic? Or does it have some other stuff mixed in there? I'd recommend actually buying it from a schools/colleges/universities/research chemical supplies wholesaler, but you're gonna get stiffed for the cost of it.

Here in the states the primary industrial use for oxalic is in paper making . The oxalic bleaches the pulp to make white paper so it is known as " wood bleach".
I don't think the hardware stores sell it, But I have bought oxalic acid from industrial paint suppliers to bleach stains out of oak flooring

pumpy schwartz 12-19-07 03:19 PM

http://www.woodcraft.com/family.aspx?familyid=5535

Falanx 12-20-07 03:59 AM

Quote:

Originally Posted by velonomad (Post 5838132)
Here in the states the primary industrial use for oxalic is in paper making . The oxalic bleaches the pulp to make white paper so it is known as " wood bleach".
I don't think the hardware stores sell it, But I have bought oxalic acid from industrial paint suppliers to bleach stains out of oak flooring


I shall remember that... cheers :-)

Iowegian 01-02-08 10:40 PM

I've bought oxalic acid here

jemoryl 01-03-08 09:29 AM

I've seen it done, but why? It looks like crap!

ColinT 01-04-08 04:58 PM

What about this stuff. The landscapers use it on their bare shovels in the beginning of the season so they dont rust. You will probably have to do a new coat once a year to keep up with it though.

http://www.rustoleum.com/CBGProduct.asp?pid=42


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