Lots of topics on this subject, but I would appreciate your advice on what sequence I should use my existing laps in, and what Diamond (and or Cerium).
I have a 10mm Copper, Batt and Tin that have been resurfaced and untouched, and a 6mm Copper I suggest would be ok for a courser grit.
I have a 120, 320, 600, 1200 , worn 1200 and a new 3000 topper lap; reserving the courser laps for cabochons.
Regards,
John
Have a look at the Dop techniques remember the pre polish is most important
First you need to check the true cutting condition of the laps, ie are they flat and is the grit size true. Many of the 3000 toppers around do not give a good finish ready for polishing.
Then forget the 120 - it will cause too much damage in depth to be useful for anything other than very rough preforming of very large chunks of stone.
Cut accurately on the 320 (if it passes muster as above), then smooth with good 3000 mesh diamond on copper - make sure the lap surface stays properly wetted when doing this; there is a tendency for the water to miss areas and the resultant dry spots will give a poor finish.
My preference for polish would probably be your tin lap (if it really is tin), used with the "Frank Dickson mix" of 50000 diamond in Teflon
The other night I tried dripping water over the copper lap charged with 8000 diamond (after cleaning off the snake oil with metho) as I cut some quartz and was very happy with the result. No scratches and a nice matt finish. Previously I had only achieved this with the Lightning Laps and water. Afterwards I dressed with snake oil before putting the lap away to prevent corrosion.
I have added a couple of drops of dish washing detergent to my water reservoir to act as a wetting agent.
I've also tried it with my zinc lap charged with 3000 diamond. The lap became dirty quickly with sward embedded in the lap surface, but seemed to cut well without scratching. I'll need to use a faster drip as the higher cutting rate left some stone powder around the edge of the lap.
The beauty of using water is that it continuously cleans away the swarf and is thin so less pressure is needed to keep the stone on the cutting surface.
I am interested in knowing if there are any pittfalls (such as the dry patches you mentioned) to using water and hearing if many other people use water on their metal laps.
regards
Gordon Perkins.
PS: thanks for removing the advertising from the Forum.
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