Best way to polish alloy

[rolesyboy]

Hi. I have various bits and pieces that I would like to polish to a high standard eg a rocker cover. It has some pitting to the surface and so I wondered would I have to get it on a lathe or milling machine to 'skim' the top? Never used a lathe or seen one in operation to know th answer. Also what steps next? I have a bench grinder with polishing wheel and paste but wondered what the best process to get the best results. Cheers. Mark

[Tim]

It depends on the depth of the pitting. If its badly damaged you may need to hand sand by working through various grades of wet and dry paper to remove the pits. If the casting has porosity, you may not be able to sand them out, by taking the top layer off you'll just open up more bubbles beneath. A polishing buff on a bench grinder is the next step, again there are various grades of cloth wheels and abrasives to work through. Professionals use a hand held tool that looks like a bench grinder with a long shaft and a handle, but for something like a rocker cover a bench grinder is fine.

Tim