Galvanised 7 chassis?

[Goochie]

Everywhere I look I see threads about rusting chassis on 7 type cars and this got me thinking, why on earth dont the manufacturers galzanise the chassis before powder coating it ? I realise that theis would require a large dipping tank but a place I used to work at produced similar sized things that were sent out to be galvanised so it should be possible.

Obviously it wouldnt' be quite so suitable for builds where you need to drill lots of rivet holes but for many it should be a viable option?

[Compo_Simmonite]

Personally I'd have it done - but regard it as a rustproofing coat rather than final finish. Etch primer and then topcoat is the way i've gone with my new galv chassis on a Land Rover and will be doing the same on my Herald idc.

There are different qualities of galving. Cheap means probably very little care is taken and not recommended. I found a firm, in Liverpool, who specialise in quality finish of delicate items and their "party trick" is doing body panels which most galv'ers would distort. At one show I saw a Fiat 500 that they had gal'd the whole shell !

With galving you cann't have any enclosed sections otherwise the process will cause the air trapped inside to expand and burst open welds etc. That means EVERY such area needs to have holes drilled and that might be the killing factor on having a 7 chassis done due to possible weakening.

Another option is having it hot metal sprayed but of course that won't cover any internal sections.

Probably the easiest option is specify unpainted from manufactueer and use POR 15 ?

Paul H

[Shaun_E]

My Caterham chassis was zinc phosphate primed before powder coating when I had it refurbished at Arch Motors. I'm pretty sure they are all done this way now.

[thescamper]

Compo_Simmonite said:

With galving you cann't have any enclosed sections otherwise the process will cause the air trapped inside to expand and burst open welds etc. That means EVERY such area needs to have holes drilled and that might be the killing factor on having a 7 chassis done due to possible weakening.

But at least this weakening can be mitigated against whereas weakening from rust which cant be seen cannot.

[The Black Flash]

I looked into this for mine, and was advised against it by the galvanising firm.
I've heard that dip galvanising is very hard to do on a tubular chassis, ending up with pools of zinc and uneven weight distribution.

Would be nice if there was a way though!

[Goochie]

The Black Flash said:

I looked into this for mine, and was advised against it by the galvanising firm.
I've heard that dip galvanising is very hard to do on a tubular chassis, ending up with pools of zinc and uneven weight distribution.

Would be nice if there was a way though!

That sounds like a rubbish excuse to me - I dont see any "pools of zinc" creating anymore weight distribution problems than the driver sitting on just one wide of the vehicle, or carbs hanging off just one side of the engine.

[minor5]

the next problem is that hot dipping causes one hell of a lot of distortion!

[Mr2Mike]

minor5 said:

the next problem is that hot dipping causes one hell of a lot of distortion!

This is the main issue, a typical 7 chassis would come out of a hot dip tank looking like some kind of modern art sculpture, and would never be usable.

[elwe]

It would be easier to just make the chassis from stainless (the right grade of course!) which has been done. This also gets over the problem of drilling holes during the build. Of course the right grade of stainless suffers from ligt surface rust in the presence of salt so you either have to keep it polished or paint it. I am opting for the later after trying the former.

[singlecoil]

Galvanising does add quite a bit of weight, too.

I prefer to paint the chassis. Good quality primer, then two coats of something tough, and different colours so that when you put the next coat on you can see where you need to paint!