Plating a chassis - is it possible?

[Mike313]

This is probably a silly question. Feel free to laugh .
The back-ground to my question is I've just been watching a Youtube video about galvanising (I need a life..).
Some of the body-off re-builds documented on here show extensive work being done to the chassis and I just wondered if it is possible/feasible to have the chassis galvanised? I've read that hot-dip galvanising can distort the metal but what about electro-plating? Also can other metals besides zinc be used, such as copper-plating to protect against rust. My thoughts were - you could custom build a bath to fit the chassis into - either in fibreglass or even simply build a strong wooden frame and drape a heavy duty tarp into it to form a bath. Could it be done? Would it work?

 

[petak]

Had some toughs about that but got answers and decided to skip it.

Hot-dip galvanizing is hard to do because plates are tin and would for sure wrinkle when you put it in hot bath.
It can be done if you first slowly heat chassis up to zink bath temperature, then dip it in zink bath and then cool down slowly to room temperature... I could not find anyone who is capable of doing it (in Croatia)

Problem with electroplating is that it would get zink only on outside part of chassis..
Zink would not get in any hole....
So it would be safe from road chip stones but not from internal rust when water lay down in holes (sidemembers and crossmembers)
This can be easily done (and should not be so much expensive), and afterwards fill in sidemembers and crossmembers with car body wax

I decided not to go that way.

But would like to see if someone can do it. Very like....

 

[chudson]

Electric galvanizing is very thin and doesn't protect as well as hot dip. But it would reach the inner surfaces of the body. There are some holes that would allow the water to float inside ( maybe a few extra holes would have to be drilled ) The problem is removing all the paint and wax from the inside before doing it ( acid wash would be required.
But eletric plating isn't just the tank and water. You need appropriate rectifier to do it and in my opinion it isn't so easy.

 

[Mike313]

Thanks petak & chudson.
Some more questions ( ) could the thickness issue be addressed by multiple sessions of electroplating? Likewise, is copper-plating effective against rust - just thinking of copper roofs I've see; they develop that green patina which seems to protect them from further corrosion .....

 

[malcolm]

Copper is between nickel and zinc in the periodic table which is a good start. You need the coating to be more reactive than iron in order for it to corrode in preference to the iron (steel is mostly iron). But copper is not used as a rust prevention coating on steel. Probably the problem with copper is it forms the green oxide which stops it corroding so much so the iron starts corroding instead. (From The Fredrick the Frog Book of Chemistry Guesswork).

I thought about this sort of thing at one point. Galvanising shops are a bit rough and ready so the floor panels will likely distort. The floor panels are the only thing that stops the chassis from twisting so chances are that won't be straight after the process. Petak's idea of doing things slowly might help. I ended up using a 95% zinc paint on mine (Bilt Hamber). I think that did help a bit as there are scrapes underneath I've not got around to fixing that aren't rusty yet.

 

[Mike313]

Thanks Malcolm,
Well if Fred the Frog said it, it MUST be true
I hadn't thought about the periodic table, decided to have a quick look and the first link I clicked on was 'The Periodic Table of CARS'
http://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=394
Not relevant to this topic in fact not much help for anything but a (little) bit funny (-ish).
I read that electroplating can give uneven deposits, with more metal being laid down near the electrical connection on the item being plated. I was thinking that this might be improved doing the electroplating process slowly and then moving the electrical connection to different parts of the chassis at timed intervals. Maybe I'll get around to doing a little experiment later in the year ....

 

[malcolm]

Fredrick the Frog liked that - you are the first person to believe anything he says.

Can't see any harm in electroplating a chassis using metals other than copper. The inside of the chassis members are in primer so it won't be so effective in there, but it will likely help elsewhere if you give it a good shotblast first. Shotblasters are as clumsy as galvanisers and can distort panels by doing them too quickly and getting too much heat in. I did mine myself.

With the chemistry stuff I can imagine the plating would attracted to the electricity connection. I've only done it to A level and haven't tried anything practical. Moving the clamp around will probably help.

 

[iMacThere4iAm]

I've recently been reading up about electrolysis for the purpose of rust conversion & parts cleaning. It would seem that electrolysis only takes place on surfaces of the part which have direct "line of sight" to an anode. I guess electroplating would have the same restrictions, i.e. that it wouldn't coat inside surfaces.