Lap contamination query

[FlashGP]

I would like the opinion of experienced faceters and lap manufacturers on this issue.

I have been teaching beginners to level and sand the backs of their open backed settings on worn 240 and 600 latps.  Recently it was mentioned this may contaminate laps and cause scratching of the stones

My thought in the issue has been that as silver is softer than most of the stones we cut any residue on the lap is likely to wear off as the stone is being cut. 

Does anyone know what metal is used to bond diamond to the lap on plated laps.  Is it likely to react with silver?

I have a set of diamond knife sharpeners which I have used to sand silver, hone tools and put bev ed ls on stones to be set and have not noticed any deterioration in the last 10 years.

Your views??

regards
Flash

[REXL]

The only metal that I know of that will react with silver is mercury and that would not be in a lap.
If the laps are washed after use then how can they scratch?

REXL

[jhonnygem]

Hi FlashGP I don't know about silver scratching your stones, but I once flush cut a inlayed  silver ring. grinding it on a 220 grit diamond wheel , it clogged the wheel really bad. I still used the wheel, but it never worked right again, and the silver wouldn't come out.

[REXL]

If you want to save your laps. Get a large ceramic tile or some plate glass from local recycling centre. Glue strips of wet/dry paper on using disc adhesive so you can peel off and replace when worn. You can even stick on strips of leather or felt for polishing. This will give you a perfectly flat, hard surface to work on.
REXL

[FlashGP]

Thanks,

I was sing wet and dry on a sheet of glass, but found the flat lap much faster and we were going through heaps of sandpaper.

On the topic of a clogged lap, have you tried to use Solvol on it?  It cleans most things from my laps, I also use a bit of cuttlefish.

cheers