Galvanising Bodyshells

[paulk]

Ok its a bit of a rant but here goes

How do modern manufacturers manage to galvanise bodies?

I know some use galvanised panels and then braze them together but I'm sure someone must just dip the plain shell. If so How?

The reason for this question is yet again I have picked up a galvanised steel building frame for work to find that the galvanising is frankly pants (big frilly pink pants at that)

The section is 3-6mm thick so there is little problem of heat deformation but they still manage to make a complete dogs dinner of it nearly every time.

This got me wondering How do car manufacturers manage? If they used the Muppets I use they would have lumps, bumps and drips all over the place and would scrap more shells than they sold.

If anyone knows please tell me because I just can't imagine how they do it

[Alec]

Hello Paul,

I would doubt that they use a hot dip process as your 'Galvanisers' use, and also pre galvanising panels then asssembling to make a shell is also impractical as the welding would burn the zinc coating.
My best guess would be some sort of electrolysis process so as to put an even thin coating. I would imagine that the hot dip process puts on a relatively thick coating.

Alec

[paulk]

I know someone does use pre galved panels and then brazes them!

I've seen the word "Galvanised" used in sales brochures and always thought this only related to dunking steel in molten zinc ie Hot dipped galv surely electrolysis only gives electroplating?

[Alec]

Hello Paul,

who does that, as brazing in itself is a rare method of car production except for tubular frame construction. (E Type Jaguar front subframes are brazed, for example.) However any welding or brazing on the galvanised portion removes the protective coating at the weld area?

Galvanising as a word indicates an electrical process which really is a misnomer for the hot dip process.

Alec

[jonathon]

The best preservation process we have come across has been the acid dip then e coating. There has been a post on this previously, but if you require further info please pm me.

[lowedb]

The steel is pretreated as it's made. British steel used the trade name Zintec, but other manufacturers do the same stuff.

I assume the coating is thin enough to allow the spot welding process to still work.

There's then an electrocoat put on top of the finished shell by making the shell an electrode and dipping.

[paulk]

I've spent a while looking back through my stuff to find out who brazes there bodyshell and can't find it.

The info I had was from Either EWM or Fronius both welding machine manufacturers who I spoke to last year about some new kit. The Ewm which I bought has a brazing feature but thats about all I know

[jtd.75]

I seem to think that there was a thread on here about DIY E/plating but I have been unable to find it, or did I read it some where else!! can any one shed some light on this topic please

[paulk]

Frost do various kits for small part E/plating with chrome or other various finishes.

They aren't cheap but you can keep on coating whatever you like with new fluid.

[Alec]

Hello Paul,

not really applicable for bodies as you need to immerse the article to be plated. By the way the fluid is an electrolyte, you also need the (consumable) plating material as small ingots to actually plate your article.

Alec