As we have stripped down the assembly, it’s time to do some “finishing” prior to a (hopefully) final erection of the major components.
At the SBA social in Hereford in the Autumn John Winn had given a talk on Nickel Plating as a way of reducing the polishing needed to maintain the engine. Given that Befur is destined for Salty Water this seemed like a good plan. I had done plating in the past with complete success, using a Dynic Nickel Plating kit on the loco, so decided to have another go on the bright-work on the engine. However, on the last batch of plating I had contaminated the solution by letting the brass anode hangers get into the bath (even though they were varnished over. So it now produces a rather nasty looking black (but corrosion proof) finish.
Dynic seem not to exist any more, so eBay provided replacement Nickel Salts (Frost Restorations), and the local gardening store provided a nice plastic trough capable of holding the rather larger parts needed on the Leak.
I had not done any plating on steel or cast before, and did not imagine it would hold any problems. The whole game plan is to CLEAN the parts to be plated – any failure here and you WILL get crap results!
You can use an Acid Bath to start with, but Dynic provided de-greasing solution that you boil the parts in, and then you scrub and wash them repeatedly using scouring powder – and DO NOT TOUCH the parts once they leave the de-greasing tank.
Well, we followed the previous plan, with mixed results – everything “looked” OK, but after a short time tell-tale rust was showing thru but not on the really polished parts of the components (The parts rust very fast (10 mins) in the open air as they are SO clean).
So some analysis suggested that we had failed to get the grease out of the minute holes in the less polished parts of the components, so back to the start – stop-off the bits that were OK with varnish, re-boil the parts in the de-greaser, re-scrub and re-plate. The results look pretty good to me… See Pictures below>
Connecting Rods, Cleaned waiting under water for the plating Tank
Scrubbing after degreasing – each component is scrubbed then washed at least 3 times.
Like any Chemistry this is messy – Chinese Fish-tank Heater, Maplin Constant Current Supply, Bath, anodes and components.
The Engine Columns in the Plating Tank (Nickel Sulphate provides nice colour)
The end result seems quite nice – I stopped off the sliding surfaces on the piston rods – we will see how the plating survives in the stuffing boxes!