DIY electro plating

R

rogerthebodger

Well-Known Member
Joined
3 Nov 2001
Messages
14,330
Visit site
I have a number for small components (gears) made of plain steel to be fitted inside my new yacht that I would like to protect from rusting.

The options are

1) print, but the paint would wear off

2) zinc plate

zinc plate would be best and has anyone done this at home say using a spent anode and 12 VDC battery.

If so what is needed and what problems would there be

I do not have a problem with H & S except my own
 
0r, if you really really really want to zinc plate them, you can buy a kit, which isn't cheap. The process isn't as straightforward as it may seem, and involves nasty chemicals, regulated currents ....
 
I have tried DIY zinc plating some years ago on some car parts, although it worked I was not that impressed with the finish and now I would take any parts to a plating company (probably works out cheaper)
 
In a previous life as a science teacher, I tried plating with various metals, zinc, nickel, chromium, copper and even silver. None really worked apart from demonstrating the principles of electrochemistry. The coating (where I actually got one) was soft, dull and powdery and readily rubbed off. I found out that the process is highly technical, requires careful control of current, voltage and acidity of the plating solution together with thorough preparation processes.
 
The best DIY way of plating is soldering, OK on flatish surfaces but not gears,you need a good flux and the steel must be clean using a gas gun and a wiping cloth, armature winders use a solder with a silver content which works reasonably well, but as suggested why not take to a plating works.
 
The corrosion protection of steel by using a zinc coating is directly propostional to the thickness of the coating.
Electroplating can typically achieve about 8-10 microns (there's 1000 microns in a millimtere), while hot dip galvanizing (on a gear) would probably be about 120 microns.

Further, electroplating is not metallurically bonded to the steel where hot dip galvanizing is. In fact HDG is an alloying of zinc and the metal, and consists of several layers of different ratios of zinc and iron, all overcovered with "pure" zinc. (Its not technically pure, but perhaps 98%)
Its not difficult to seperate the electoplated zinc from the iron, while its very difficult to seperate the HDG zinc from iron.
The alloy layers in a HDG coating are harder than mild steel. In a way HDG puts a hardened layer on the item.

The wearing faces of the gear will probably wear off the zinc even though its hard, but thats not the high corrosion area in a gear.

Electroplating is more expensive that HDG.

So, in this application, why would you even consider plating over galvanizing?
 
Whatever you have on the contact faces of the teeth will wear off but you will probably have some kind of lubricant on there which will prevent corrosion. The sides of the gears can be painted if they are not bearing on anything that will rub the paint off. Or you could coat the gears with some kind of corrosion inhibitor, e.g. Quicksilver, or is appearance an important factor?

What are these gears for anyway? If they are only lightly loaded you could perhaps use plastic or non-ferrous metal instead of steel.
 
My plater makes a minimum charge of around £30 for most plating materials save for the precious metals. He will mix components if they are not too disimilar. But HDG is a much better choice although propbably more difficult to find a professional for a small batch.
 
when in apprentice training school we made various tools for our own use . instructor heated them up and plunged them in oil . the surface went black and stopped swetty fingers making the surface rusty. not plating but quick and easy to do and better than nowt . has any one else experience of this
cant remember if it was any good long term.
 
If it was that easy I would be out of a job.

Zinc plating by itself is not very good as a rust preventative. It needs a coating of at least 8um, as had been said already, but then needs a top coat of passivating. Hexavalent chrome passivating was the accepted method, but now we have to use trivalent passivate for 'elf an safety.

I don't think that DIY electroplating will work at all. Too much nasty chemical needed.

If you want to go down the electroplating route use a zinc/nickel alloy plate with a trivalent passivate. This gives exceptional corrosion protection with only 8um coating. ( Any threaded component would become almost unuseable with HDG.)

PM me if you need more details.
 
[ QUOTE ]


Further, electroplating is not metallurically bonded to the steel where hot dip galvanizing is.

[/ QUOTE ]

Electroplating IS bonded to the base material by the formation of an "epitaxyl layer", whereby the first atoms of the coating are alloyed with the base. Without this layer all subsequent deposition would fall off.
 
I spent the first 12 years of my working life as an Electroplating Chemist, working for major chemical supply companies testing literally 2,000 electroplating solutions per year.

I have seen amateurs who think they can produce their own solutions make total f'ups and ruin previously good pieces of metal (and plastic - yes you can plate plastic as well). This is why the specialist chemical supply companies make a good living, they have invested years into developing additives (and potions) which make metal plate shiny and adhere to substrates.

As suggested above either get it plated professionally, or get it HDG.
 
[ QUOTE ]
I have a number for small components (gears) made of plain steel to be fitted inside my new yacht that I would like to protect from rusting.
The options are
1) print, but the paint would wear off
2) zinc plate


[/ QUOTE ]

Anything on the gear meshing surface is going to wear off in pretty short order - so I'd consider cold-galvanising (aerosol spray zinc paint) or Zinga (if you're very rich) to non-meshing areas. Then apply a synthetic grease to the meshing surfaces. Power-Gel 250 is excellent for this kind of job - being a food-factory grease it withstands salt-spray and sticks like goose-sh#t to a blanket.
Colin
 
Thanks guys, it looks I need to find a local electro plater.

The items are for remote operation of some seacocks that I willnot be able get to very easy and they do heve threaded holes and quite small gear teeth so HDG would not be an option.

I do use HDG quite a lot on the internal structure of my new steel yacht
 
You could always plate with hard chrome. This would give wear resistance, as well as corrosion resistance. It will probably require several layers of plating. The car trade used to use micro cracked chrome plating, as this reduced corrosion. I believe it changed the electrical characteristics of the surface.

Philip
 
[ QUOTE ]
( Any threaded component would become almost unuseable with HDG.)

[/ QUOTE ]

You can have components Hot Dip Galvanize Spun where you dip the component and then spin it 'ala centrifuge' to remove excess zinc.
It works well with threaded components.
 
You must log in or register to reply here.

Share this page

Top