Quote:
Originally Posted by jf
I've successfully plated over steel and zinc with copper. Buffing has been a frustration. First of all, sandblasting off old chrome does not work with glass beeds. You must use the black stuff (silicon carbide?). (Not explained in Caswell instructions). When you use the black stuff it leaves a rough finish, so then you have to sand, sand, sand before buffing. OK now on to buffing. I'm using the white compound as recommended by Caswell. The black gunk (compound) created while buffing sticks to the part. Some have said that the part is not hot enough and the compound is not liquifying. If I put enough pressure on the part to heat it up, that wears off the copper and I have to replate copper. Buffing is not rocket science so do I have bad compound, bad buffing wheels or what. What am I doing wrong...too much compound?, too little compound?, wrong speed?, too much pressure?, too little pressure?, too hot?, too cold?. Somebody out there has to have a source for buffing instructions other than Caswells, which are worthless.
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I'm not a plater, but:
The buffing compound is sticking because the part is still too rough for that compound. When I'm polishing aluminum, as soon as I see white rouge sticking, I immediately go back to emery compound to get out the unseen scratches that I missed the first time.
If you have to polish that much after the plating, the part was too rough to begin with. You need to do all your smoothing _before_ you plate. It is my understanding that the part needs to be _polished_, not just sanded, before plating begins. Furthermore, once it's completely polished I do believe it's to be chemically treated to give it some tooth (but not roughed up) before plating.
Have you asked this question in the plating forum?
P.S. - I have successfully used greaseless compound to remove chrome plating (the finest grit that will work), although it may be rather time-consuming if the part is of a complex shape. I also understand that you can somehow use the plating equipment to "reverse" the system to remove the plating electrochemically.