Re: surface grinding copper
Surface Grinding of copper...
Easy. Use a solid metal wheel - a dead soft aluminium, and a hard and fine compound - such as a automotive valve lapping paste for a fine finnish.
The hard material embeds in the aluminum, and this grinds the copper away.
Use a mix of lubricants, a deodorised kerosine ~ 10 - 15% for a thinner, and a boundary lubricant such a lard.
If your doing this commercially, use a bottom sucking recirculating pump, to keep it all cool and the abrasive in suspension.
For a 1 off, get your copper block flat, with hammer or lathe etc., and get some 6mm or 1/4" dead soft pure aluminium sheet ~ 30cm x 30cm, some thicker cloth such as felt or windcheater material to carry the sheet and some chip board to carry the lot; then use some automotive valve grinding paste, then rub the copper block in small circles over the entire glass area, and then slowly rotate the copper block to eliminate any abberations caused by uneven finger pressure.
This will bring it up a treat.
If you can't get dead soft 6mm or 1/4" aluminum sheet; some plain kind of fiberboard will do fine.
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