Author Topic: Cheap home plating  (Read 289 times)

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Offline Barnett

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Cheap home plating
« on: November 29, 2020, 10:14:38 PM »
Merv asked if I could post this here in response to a thread running about control cables and me suggesting you can make your own and reuse the components if required. Care with brake cables needed though!

Home Plating Small Parts
E.G. Nuts, bolts, washers, spacers, control cable ferules and compnents.

Find a tallish large glass jar 3/4 - 1 litre, (plastic at a push but not ideal), buy some white vinegar, (cheap!), and find a power supply. An old mobile charger is good, 1/2 to 1 amp 5-6 volt, use batteries, at least 3 volt if you can't find one. Strip wires on output of charger and add a couple of crocodile clips, don't worry about polarity at this stage. Grab some salt, white table salt. Buy a yard of 16amp household single core copper cable, strip and coil up for later.

For Nickel plating you will need some nickel, ebay. Best to use purest possible, 98% plus, I use welding rods for cast iron.

Make solution, you will only need to do this for the first time i.e. once, it will keep forever. Fill jar with vinegar, add and dissolve about two teaspoons of salt to improve conductivity. Warm contents by standing in bowl of hot water. Remove and place on stable surface. Bend a hook in two of the rods and hang over jar in solution as far apart as possible and NOT touching, keep about 1/2 inch off bottom of jar. Hook up power supply and switch on. Observe, the rod that fizzes is your cathode, mark it as such.

Leave for 1 1/2 - 2 hours, the solution will turn a light green, nickel ions are now in solution. You will notice the anode has been eaten away somewhat. As you use time after time the solution will darken as it gets stronger, this is normal. Now ready to plate! Switch off power, remove rods and pop lid on jar, place out of reach of kiddies.

Steel parts must be completely free of rust, dirt and grease. Its all about preparation.
De-rust chemically or using wire wheel on bench grinder till shiny clean, degrease with brake cleaner, wash in strong warm detergent and thoroughly rinse, don't touch with ungloved hands at this point.

Wire up your part with pure copper wire, household wiring pure enough, impurities will give bum results. Take care how you wire part thats going to be in solution, too tight and it won't plate underneath or cause a shadow band. Hook the other end so that when hung in jar using a pencil across the top it doesn't touch the bottom or the anode.

Get your solution and preferably warm up by standing in bowl of hot water, plating works better when warm, 30 - 35 deg. Remove lid, hang part on pencil. Introduce anode rod only, not cathode, your part is now the cathode. Clip power supply negative, (cathode), to your part by clipping on to copper wire hook hanging over pencil. Clip positive to the nickel anode rod in solution. Keep part away from anode and avoid it touching side of jar. Switch on!

Your part will fizz imeadiatly and begin to plate. How long? Depends on loads of factors, current, voltage, area of part, strength of base solution etc.
For a nut, about 20 - 30min. Stir solution very gently with a plastic straw, or wooden splint a couple of times during plating, reposition complex items for even plating every 10min, i.e. just turn dangling part around 180 deg on pencil rod.

Tip, measure part with callipers before plating, check plate thickness after plating. I generally aim for about 0.05 - 0.1mm  max, which is loads.

When finished, rinse part well in water, remember there is salt in the solution! If your very lucky part will be quite bright and looking almost like chrome. Mostly its a matt finish but can be polished up with metal polish. Nickel is quite inert and corrosion resistant but not as good as having a layer of clear chrome on top! Polish it with some wax polish and it will be fine. Alternatively you could clear lacquer spray, it all depends on what your doing and where its going to end up etc.

Store your covered solution safely for next time. If the anode gets dirty and or crumbly clean off under running water using washing up sponge scourer, eventually you will need to replace it. Keep the solution clean! Remove any visible solids by filtering out through coffee filter paper in a funnel.

Getting more technical - bigger containers will need agitation, you will need to visit a tropical fish supplier shop! Improved results can be obtained by acid etching with dilute hydrochloric acid before plating, rinse in water after acid dip! Acid dip for a min or so, no longer. Use dilute HCl, dangerous! Can get from b&q, brick cleaner. Dilute 50/50. Do outside shed, fumes eat everything! Nickel plating is very reliable though, this is not normally necessary.

Using the same apparatus you can copper plate and zinc plate as well. Copper won't plate direct onto steel, nickel plate first. Copper solution will be feint blue. Zinc will almost always be dull grey unless you use brightener, alternately just use metal polish afterwards, shines up nice. Zinc solution has no colour. Get the purest metals for your anodes and cathodes you can.

Do in ventilated area, no naked flames near plating jar. Make sure your power supply is fused with low rated fuse on mains side.

Good luck, its fun, and cos I'm tight as a ducks @*#£ cheap!!
 

Offline mervin

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Re: Cheap home plating
« Reply #1 on: November 30, 2020, 04:29:56 AM »
Cheers Dave

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