Thread: Galvanic corrosion.........

Are zinc blocks/sacrificial anodes as used on steel boats of any use on a land rover?

and also used in hot water tanks................im thinking not unless you park in a dam or swimming pool

Originally Posted by Andrew Morris

Are zinc blocks/sacrificial anodes as used on steel boats of any use on a land rover?

Yes, in the common rust areas.

How so? I thought what Andrew was describing was more or less ERPS???

Originally Posted by uninformed

How so? I thought what Andrew was describing was more or less ERPS???

No, not really though I'm sure the designers of those things were thinking along the same lines.

Zinc blocks and/or sacrificial anodes are just where 2 metals are togther and electrically connected. When combined electrically, one of the metals will corrode in place of the other until it is consumed, and then the other will start to corrode. Galvanising (Zinc coating) is a great example of this, as it not only forms a protective barrier but works through cathodic protection - note how the edges where the steel is uncoated also doesn't rust.

Originally Posted by uninformed

yeah Ill have to try another, Where im going atm is my local nut and bolt specialist.

Nutz+bolts in ipswich and my personal fave

GM bolt in about the same area. One of the guys there takes it as a personal challange to get what you need in about the same way I take it as a personal challange to get old engines that dont want to to want to again.

Originally Posted by Andrew Morris

Are zinc blocks/sacrificial anodes as used on steel boats of any use on a land rover?

yes, but a bit cumbersom to install. I've heard tell of a guy who cast up a heap of really small ones in the shape of a cup washer and just bolted them in place where needed.

Originally Posted by Andrew Morris

Are zinc blocks/sacrificial anodes as used on steel boats of any use on a land rover?

This is effectively what galvanising is. The problem with using the zinc block idea on a Landrover is that the protective effect only extends as far as the vulnerable metal is immersed in the same body of liquid as the zinc bloc. This implies a very large number of blocks, unless your vehicle is completely submerged full time. In practice, use galvanised steel where possible - the protection will extend from the galvanised steel to surrounding metal, to the extent that the surrounding metal is in the same bit of moisture. This usually works quite well using galvanised fasteners, as away from the bolthole the metal can be protected by moisture impermeable paint, which is likely to be damaged under the fastener, which is also where mud and water will be trapped.

John

Originally Posted by redneb72

Can anybody recommend a good inhibitor - i.e.. grease or the like?

"Duralac jointing compound DTD369B prevents bi-metallic & galvanic corrosion

Key Features

• Between aluminium alloy plates, extrusions and bolts or rivets used in buildingapplications.
• In general engineering applications where dissimilar contact cannot be avoided.
• In vehicle building where aluminium alloy contacts steel.
• For marine application where corrosion is accelerated by brine concentration.
• In close proximity to the sea where a salt laden atmosphere will meet with structures and set up electrolytic cells.
• In aerospace where rivets/bolts are secured into aluminium plates DTD 369B

Available in a 150gm tube, 500gm, 1litre and 5 litre tins Uncured Properties
Colour Yellow
Viscosity Viscous liquid
Shelf life @ 20C:12 months in dry conditions"

$32.95 a tube at www.whitworths.com.au. A tube will go a long way.

And for bolts etc. try

Bolts Nuts Screws Online |bolts-screws-decking screws-rivets-stainless steel-socket head cap screws- Stainless Steel-High Tensile bolts-screws-socket screws-decking screws and rivets Phone 1300 589 836

cheers

Wayne