Polishing Lap de-lamination???

[FlashGP]

Was trying to polish cat hairs out of a large facet on a comp entry I am working on, when at 10.40pm disaster struck.

The facet ploughed into the lap and shaved about 8 wafers from my Batt Lap as the stone bounced.  I was using 100k polish with Snake Oli as a libricant but polishing with the lap running counter clockwise (front to back on the dop side).

The furrows are about 0.1 mm deep 3 to 4 mm wide and 6 to 10mm long.

Does anyone know if I was polishing too fast or let the lap run dry momentarily or ...

Looks like I'll have to send the lap for re-surfacing. 

Regards
Gordon

[Moth]

Flash you have my sympathy I have been wrestling with a smoky quartz petal cut for a comp.  Reckon I have put 60 hours into the f$%^ing thing - first one I got to the polishing on the pavilion and was at 50K when deep scratches started - changed to cerium but couldn't get rid of the scratches and ended up ripping the stone off the dop and giving it an aerodynamic test across the room. Second stone I got to the pavilion stage and resurfaced my steel lap (180 followed by 360 followed by 600 wet and dry) and was doing ok priming the lap with WD40 before 50K paste (singer oil and sorbilene) then the CP fragmented so I had to start again - finally got through the pavilion with 100k (tin lap) and now just about finished I normally cut a comp stone around 94 - 96% but think I have left a couple of meet point mistakes in this one but at least the bloody thing hasn't beaten me.

[FlashGP]

Hi Moth

Shame you couldn't salvage the couple of earlier stones for Jewellery.

Luckily my CZ seems unharmed.  Am going to try 100k on the darkside to get rid of the cathairs.

The design only has 13 meetpionts so I need to get them all spot on.

I have a steel lap from the 2nd hand relic I bought years ago.  How do you find the steel lap compared to the electroplated laps?

Regards
Gordon

[Moth]

I like it and simply resurface by seating  various grades of wet and dry on a glass sheet then I use a little jig I made to hold the laps while I re-rough the surface.  With CZ I find there will always be a facet which either scratches or orange peels - I polish 3,000 and 16,000 (Copper Lap) then 50,000 steel and 100K tin lap but sometimes I repolish with the 50k and then return to the 100k which seems to work for me - I am pretty slow with CZ as I always have to leave room between meet points and polish up to them for the above reasons

[Spaghetti888]

Was trying to polish cat hairs out of a large facet on a comp entry I am working on, when at 10.40pm disaster struck.

The facet ploughed into the lap and shaved about 8 wafers from my Batt Lap as the stone bounced.  I was using 100k polish with Snake Oli as a libricant but polishing with the lap running counter clockwise (front to back on the dop side).

The furrows are about 0.1 mm deep 3 to 4 mm wide and 6 to 10mm long.

Does anyone know if I was polishing too fast or let the lap run dry momentarily or ...

Looks like I'll have to send the lap for re-surfacing. 

Regards
Gordon

Hi Flashgp, I was just about to post the exact same thing! I was polishing a sapphire last night and the same thing happened to my batt lap (second time I have done this)
It happens to me when I have the lap running counterclockwise and place the stone on the wrong part of the lap, so for me, at about 4 o'clock rather than at 2 o'clock if that makes sense. Vice versa. For me the amount of lubrication doesn't really affect this issue.

What I did want to know, is if Batt laps are able to be dressed like tin and copper laps with wet dry sandpaper, or am I better off just sending for resurfacing?

[FlashGP]

I dressed my Batt Lap when it was new.  The first time I used it diamond collected in the m ax chining grooves and scratched, so I lapped the lap on wet and dry to remove the machining marks.

The level of dam as ge will probably dictate whether the lap neefs resufacing

[Spaghetti888]

What did you dress a batt lap charged for 100000 with?

[FlashGP]

Sanded it with 600 and 1200 wet and dry. Then scrubbed it with Solvol and finally with a piece of cuttlefish bone and Palmolive dishwashing detergent.  Then sprayed 100000 diamond on it, applied a couple of drops of snake oil and while spinning ran a piece of tumbled quartz across it to embed the diamond.  Then with a maleup remover pad with a squirt of 100k diamond on it and 3 drops of snake oil, wiped the lapclean, continuing to do so while faceting. 

[FlashGP]

Infotrunately was running the lap ccw instead of towards me (cw).  First time I have had a polishing lap grab the stone.  Previously it was the 8k on zinc during sanding.  This time flakes of lap thinner than alfoil came off.