46094

Procedure to hobby copper plate 40 cm long x 100 mm dia pipe? [New Zealand] 

August 8, 2007

Sir, You have assisted me in the past with a chemical solution for PC BOARDS great all is well however, I need to Copper-plate my Galv.Pipe about 400 mm in length and 100 mm in dia and it is galvanised steel pipe with a 3 mm wall. The pipe will be sealed/welded closed at both ends so I would not mind if the sides are plated as well. I can have the galv. coating removed in a lathe if necessary but what chemicals may I enquire should I use to Copper-plate the piece of pipe. I have a modern workshop with variable power supplies of any voltage up to 30 amps which I used long time ago for THP of PC BOARDS. I have Sulphuric acid and I have copper rods of a few sizes. Please advise me what steps to take and the procedure oh....I need a coating of about 35 to 40 u copper thickness on the drum or pipe.
Thank you in anticipation

Respectfully
Christopher (Ex-SWEDEN)

Christopher Halgryn
Designer - Auckland, New Zealand.

Hello again, Christopher. Happy to hear of the successful resolution of your previous issues.

Apparently this galvanized pipe is being used because it is handily available and the galvanizing is not required. That's good; it's much better to put the copper plating directly onto the steel of the pipe. The galvanized coating can be easily and quickly removed by dipping into hydrochloric acid. I didn't say 'safely', that's a matter of your training; the acid reacts very quickly with the zinc.

You should really use copper cyanide or copper pyrophosphate or a nickel strike on the steel rather than copper-sulphate based plating solutions because the latter will "immersion deposit" and lack good adhesion. But if you enter the plating solution "live" (with the current already on), the adhesion may be good enough for your needs.

So, I'd suggest cleaning the pipe will with a mild alkaline cleaner, rinse, strip the galvanizing, rinse, and plate. A couple of volts should be plenty, the solution should be copper sulphate with a little sulphuric acid, and supply some form of agitation.

You must have at least one plating book before you start and the Metal Finishing Guidebook is probably the least expensive and easiest to find. Good luck.

Ted Mooney, P.E.  finishing.com Brick, NJ