My Latest Nickel-Plating Tanks

[awemawson]

This was prompted by going to use my big combination wood working machine, and finding some of the rollers rather rusted  Obvious thing to do - nickel plate them.

Now I've done a bit of nickel plating before, both in a bucket and in a trough. Bucket has limited depth and trough, although the right sort of shape is a pain to work with as getting agitation to the whole length and not sloping expensive nickel salts everywhere was difficult.

So I decided to make a couple of dedicated 'vertical tube tanks' from some 6" plastic underground drain pipe. Dedicated glue on caps are available, so sealing the base should not be an issue, and a loose cap can go on top to keep dust out when not being used (ie most of the time) so the chemicals can stay in.

However, as the nickel anodes need to hang on the lip of the tube, this would prevent putting the cap on unless cunning was applied . . . . so looking in my book of cunning tips, I decided to form an inner ledge from pipe off cuts. Slicing a 1" long bit of pipe off, I then cut it so that it's circumference was smaller, and spaced it off the inner wall of the main tube with four small sections of a 1/2" pipe slice - all glued in place with solvent weld adhesive.

Worked out rather well 

Now the commercial nickel anodes are lumps about 1" square and 1/2" thick roughly cropped from a sheet. These need suspending in an inert basket that will conduct electricity. Titanium is about the only stuff that fills the bill. So I bought a sheet of 'expanded titanium mesh' and bent up some suitably long thin baskets into which the anodes will slide.

I had intended to TIG weld the join, but in the end I laced it with titanium wire - seems to work. Then I riveted on a hanging strap cut from sheet titanium that will grip on the previously described ledge.

Now usually the baskets would be placed in 'anode bags' made from polypropylene material to save any gunge settling out into the tank - not essential but nice to have. A length of supposedly polypropylene  cloth arrived today and being plastic I had hoped to heat weld seams to form bags. This stuff behaves more like cotton and chars rather than fuses so I'm pretty sure it's not what it claims, so the hunt is back on for genuine polypropylene cloth to make bags 

Currently the tanks are full of hot water doing a leak test - I'll leave them over night and if they are ok I just need those bags 

[Joules]

Nice use of Baldrick's Book of Engineering.  I suppose you can also make copious quantities of GREEN......

[John Stevenson]

So what would an engraved machine dial come out like ?

[awemawson]

Probably quite nicely. My plating has all been for rust prevention rather than looks, but if it's done at a low current density over a longer timescale it polishes up nicely with 'Solvol-Autosol' to an almost chrome like finish.

Not a good picture but this locking shaft that I did a few weeks ago came up nicely

I've previously experimented with plating over a lightly sand blasted surface and that comes up a nice matt effect

[Pete W.]

Hi there, Andrew,

I'm finding this thread interesting, thank you.          

Do you use rectified AC or smoothed DC?

I thought the 'pukka' preparation for nickel-plating was a copper flash?? 

[awemawson]

Pete I'm using a controlled lab supply at a constant current.

It's actually the other way round, steel needs a nickel flash for copper to stick properly. They call it a 'nickel-strike' :

https://en.wikipedia.org/wiki/Copper_plating