Rust Prevention

Frequently asked technical questions and common modifications/improvements
User avatar
mat_fenwick
Moderator
Posts: 7278
Joined: Tue Sep 20, 2005 4:08 pm
Location: North Wales
x 13

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.
Image

1993 1.9 TZD Turbo Estate
1996 3.9 V8 Discovery
1993 VW LT35 campervan
1985 Hyundai Stellar V8
2016 Hyundai iLoad

User avatar
BX Bandit
Backslash Bandit
Posts: 2587
Joined: Thu Aug 31, 2006 7:46 am
Location: Home
My Cars: Cars
x 1

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.
1990 BX 16V Platinum Grey
1990 BX TGD White
1960 Morris Minor Clarondon Grey
1971 Triumph 2000 Auto Valencia Blue

User avatar
Vanny
Merseyside resident
Merseyside resident
Posts: 3443
Joined: Tue May 17, 2005 11:48 pm
Location: BX Pub
My Cars: BX 16v Ph2
x 16

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.

User avatar
mat_fenwick
Moderator
Posts: 7278
Joined: Tue Sep 20, 2005 4:08 pm
Location: North Wales
x 13

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...
Image

1993 1.9 TZD Turbo Estate
1996 3.9 V8 Discovery
1993 VW LT35 campervan
1985 Hyundai Stellar V8
2016 Hyundai iLoad

User avatar
Kitch
Over 2k
Posts: 6204
Joined: Sun Jul 03, 2005 9:36 pm
Location: Fareham, Hants
x 49

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!

Defender110
Over 2k
Posts: 5898
Joined: Wed Dec 16, 2009 8:02 pm
Location: Harwood, Bolton
My Cars: Citroen BX MK1 Break.
Land Rover Discovery Series 1 200tdi 3 door
Land Rover Discovery Series 2 Facelift TD5
BMW X1
x 25

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.
Kevan
1987 Citroen BX MK1 diesel estate.(Currently in dry storage)
1997 Mercedes C230 W202 - daily driver.
2010 BMW X1 SE 2.0D Auto - Her indoors daily driver.
2003 Land Rover Discovery Series 2 Facelift TD5 - Daily driver / hobby days and camping.
1993 Land Rover Discovery 200tdi Series 1 3 door - in need of TLC