I recently received a BATT and charged it with 3000 bort according to the instructions that came with it. I used it on the pavillion of a tourmaline and it gave a nice pre-polish. I used WD-40 as lubricant and occasionally wiped the lap to remove the swarf.
By the time I finished with the pre-polish, there was a lot of swarf on the lap. I know that people use water on BATTs when used as cutting laps and don't use water when polishing with diamonds. My question, is what to do when using a 3000 pre-polish? It seems water would help with the swarf build up but I am concerned about the diamonds clumping / scratching. I would appreciated it if anyone could share their experiences.
Joined: Tue Jun 12, 2007 6:41 pm Posts: 5534 Location: Massachusetts, USA
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By the time I finished with the pre-polish, there was a lot of swarf on the lap. I know that people use water on BATTs when used as cutting laps and don't use water when polishing with diamonds. My question, is what to do when using a 3000 pre-polish?
Diamonds love oil, oxides love water. When using coarser grits on BATT to CUT, however, the cutting speed and swarf buildup is so fast water is needed to remove both heat and dust. The cooling water looks like milk when it comes off the lap. In the case of cutting, all Work is done by the embedded grit. this is why the surface finish is usually one abrasive grade better than the actual cutting grit size.
On a WD40/Oil based prepolish laps, much of the swarf is stone dust, and is a potent scratch and heat -maker. The black tint is from nanoscale metal particles, and even a fraction of a percent is a poweful pigment.
Wipe it off, and keep it clean. I use a -slightly- dampened (WD40) piece of tissue, wipe dry, add powder if the speed has slowed, repeat as needed. A perfectly conditioned 3K prepolish BATT has a lightly frosted appearance, not bright metal. This appearance means a pefect balance of diamond and fluid has been reached. As time goes on you will find that less and less diamond addition is needed as the lap surface loads.
Early on when diamond was more expensive I was often tempted to leave the "Black Stuff" on, rather than "Throw away diamond". This was wrong. The diamond that is most important in the material embedded.
Black Stuff is the enemy. keep it clean. It is not so serious to have that load up on prepolish as it is on polish.
Stone dust contained in the Black Stuff does nothing but add heat and scratch risk..it does not contribute to cutting or polishing.
Joined: Wed Nov 15, 2006 9:44 pm Posts: 1079 Location: Washington State
The only diamonds which do much actual cutting are those which are embedded in the surface of a lap. The swarf should be removed after the lap has been charged and I just spin the lap at low rpm, give it a squirt of wd40 and wipe it with a clean paper towel until it looks clean and dry. A hint of wd40 remains and provides sufficient oil to keep any excess diamond from agglomerating. Do that every time the lap builds up a layer of swarf and you're good to go until the cutting slows and then give it another shot of diamond and repeat.
I find that the lap is too aggessive with a fresh shot of diamond and so I'll run it in with a waste chunk of corundum, until the cutting is less aggressive, then give it a wipe and use it.
Joined: Tue Jun 12, 2007 6:41 pm Posts: 5534 Location: Massachusetts, USA
One pecuilarity of using the 3K/BATT prepolish is that cutting nearly dry produces a near-polish (HSN would call it "Done") and cutting wet nearly cuts and moves meets well, to the extent that stars can be cut on it.
Thanks for your comments. I will try keeping the lap wiped clean. There is definitely a lot of black stuff to removed. Perhaps I'm a cutting too much when I should be polishing.
Joined: Thu May 29, 2008 8:32 am Posts: 1730 Location: Suwanee, GA US
I use too much diamond, but I love aggressive laps. That said, if you get to much swarf, if does get a bit difficult to remove. I run a WD-40 squirted paper towel on it (which does a miracle clean) and the wipe while running. If it is too junky, doing what Gearloose does in the initial charging video... diamond and rub with your finger... cleans it off.
Joined: Thu Jan 24, 2008 4:01 pm Posts: 1902 Location: Pine City, NY and Dothan, AL
Gearloose wrote:
One pecuilarity of using the 3K/BATT prepolish is that cutting nearly dry produces a near-polish (HSN would call it "Done") and cutting wet nearly cuts and moves meets well, to the extent that stars can be cut on it.
That's not a peculiarity - it's what other laps wish they could do.
Joined: Sun Dec 30, 2007 12:01 am Posts: 556 Location: Vancouver, Canada
Gearloose wrote:
One pecuilarity of using the 3K/BATT prepolish is that cutting nearly dry produces a near-polish (HSN would call it "Done") and cutting wet nearly cuts and moves meets well, to the extent that stars can be cut on it.
My pre-polish BATT is 8,000 Diamond and it is quite capable of producing a polish equal or better than 14,000 on tin. It will cut facets on small stones, I get a lot of them. I use 8k because it doesn't seem to to take any longer to get a fine pre-polish but it does mean that the following 200k polish is instantaneous, no sweeping or rubbing needed. Saves me some time.....
Joined: Tue Jun 12, 2007 6:41 pm Posts: 5534 Location: Massachusetts, USA
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I use 8k because it doesn't seem to to take any longer to get a fine pre-polish but it does mean that the following 200k polish is instantaneous, no sweeping or rubbing needed. Saves me some time.....
There is a paradox that was explained to me by the industrial diamond supplier when I worked at the optics company:
Sometimes in certain situations finer grits actually cut faster, particularly in bonded tooling.
"More diamond particles per unit area".
It makes sense but not till you think about it. At least for me.
I understand that black stuff is bad and that I should keep the lap clean, but what is a clean lap? I can think of two criteria:
1. The lap is clean when I can see no black stuff on it.
2. The lap is clear when I can no longer wipe it with a tissue and get black stuff on the tissue.
Condition 1 occurs long before 2. Is condition 1 is adequate? If so I could save a lot of time (and tissues).
Based on Tony's comment, I've started using 8K polish on the Batt. I assume that it will take a long time for all the effects of the 3k initially added to go away, but I'm patient.
I definitely noticed the frosted appearance mentioned by Jon when I was using the 3K but it seems much less frosted with the 8K. I assume this is normal.
Joined: Tue Jun 12, 2007 6:41 pm Posts: 5534 Location: Massachusetts, USA
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1. The lap is clean when I can see no black stuff on it. 2. The lap is clear when I can no longer wipe it with a tissue and get black stuff on the tissue.
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Condition 1 occurs long before 2. Is condition 1 is adequate? If so I could save a lot of time (and tissues).
1 is adequate. Consider polishing brass or silver with metal polish. The black stuff never stops coming as long as there is any metal left. Swarf and diamond make a good metal polish. The more I use my brass XS3 the better it looks. Finely divided metals make potent pigments. As I had written someone recently, note the grease on your car door hinges. it was not black when it was applied.
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Based on Tony's comment, I've started using 8K polish on the Batt. I assume that it will take a long time for all the effects of the 3k initially added to go away, but I'm patient.
The biggest reason I myself do not use 8K is that it is too much like a polish. I fear skipping a polish step. Certain TV Retailers would probably call an 8K BATT polish "Done". We wouldn't.
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I definitely noticed the frosted appearance mentioned by Jon when I was using the 3K but it seems much less frosted with the 8K. I assume this is normal.
It is a function of abrasive particle size. People who use BATT to cut with have _really_ frosted laps.
Joined: Tue Jun 12, 2007 6:41 pm Posts: 5534 Location: Massachusetts, USA
Here is my personal 3K prepolish BATT™. This is the way it was put away last time I had a chance to cut a stone. The next time I will use it, I will apply the usual trace film of WD40, and 3K powder.
So, this lap is fully conditioned, and it will look like this as long as I use it..in other words, I regard it as being in a stable state.
Higher Magnification:
Dark spots are traces of WD40 being released from intergranular spaces. This is why "Nearly Dry" polishing works on these laps.
Recently I was trying to polish an apatite and was having a horrible time. I tried 3 different polishing laps (ultra, wizard and darkside) with several different polishes (diamond, cerium and aluminum oxide) and sometime with vinegar . Most of the facet would polish well but there would always be one or two large scratches on most facets, apparently due to pieces of the apatite breaking off and being dragged across the facet.
Following Tony's advice, I noticed that 8K on my Batt (previously charged with 3K) gave something like a polish on other stones so, I gave it a try on the apatite. Though not really a good polish, at least it did not have the big scratches. I flipped over the batt and charged it with 100K and got a nice polish, with no scratches.
I am a bit worried that I will eventually cross contaminate the lap by charging different grits on different sides, but so far I am happy with the experiment.
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