Rust Prevention

Frequently asked technical questions and common modifications/improvements
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mat_fenwick
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Re: New rust location

Post by mat_fenwick » Sat Jun 15, 2013 8:55 am

Post no. 27 on this thread onwards is the sort of thing you're talking about and what I hope to do. I might make a 180 degree fold in the metal to simulate a rusted seam to see what effect they have on slowing trapped corrosion.
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Re: New rust location

Post by BX Bandit » Sat Jun 15, 2013 9:12 am

We've hi jacked a thread here actually mate, but I'm wondering if we need a rust and body work section or at least a rust thread in technical FAQ.
That was an interesting thread mate and led me to here and also they showed a diagram of the car with injection points for cavity protection, just had a quick look but can't find one on tinternet. Anyone know of one?
Last edited by BX Bandit on Mon Jun 17, 2013 4:33 pm, edited 1 time in total.
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Re: New rust location

Post by Vanny » Sun Jun 16, 2013 8:19 am

mat_fenwick wrote:The 3 cold galvanising coatings I know of are Zinga (96% zinc), Galvafroid (90-92%) and (Bilt Hamber) Electrox (90+%).

Any thoughts on etching primer?

I find most of the zinc or zinc/aluminium primers don't tend to stick too well to bare metal or painted surfaces, even with a thourough roughing up.

My tendancy is to apply the following layers
  • etching primer
  • zinc rich primer (not needs be weld through, often a Upol one)
  • seam sealant
  • High build primer (grey)
  • top coat (cellulose)
  • anti stone chip (if required)
  • black top coat for the anti stone chip
  • laquer
Number of layers of each will dependant on how well i put the coats down, and where the paint is going (eg underside, non visible etc). All bar the anti chip is from aerosol cans for now, though that is likely to change in the near future to spray gun and compressor.

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mat_fenwick
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Re: Rust Prevention

Post by mat_fenwick » Sun Jun 16, 2013 9:00 pm

I think etching primer under a cold galvanising coating is going to negate some/all of the benefits of the coating as it will electrically insulate the zinc from the steel. Under a standard zinc/aluminium rich primer which I presume has significantly less sacrificial metal, the pigment will be isolating the zinc from the steel to some extent, so an etch primer may have little effect. Just my speculation though...
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Kitch
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Re: Rust Prevention

Post by Kitch » Mon Jun 17, 2013 12:09 pm

Another vote for PU sealant here. We use the Wurth stuff - sticks like shit to a blanket!

Seam sealer I've found cracks in certain conditions. Not what you want IMO!

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Re: Rust Prevention

Post by Defender110 » Mon Jun 17, 2013 12:44 pm

Yes seam sealer cracks if you try to apply it too thickly, a couple of thinner coats are better.
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