Polishing help for Single Stone Contest. !!

[Markos]

Inefficient pre polishing is the first thing that comes into my mind looking at your lap sequence. Skip the 1200/3000 crystalite on corundum and from the 600 go straight to oil, 3000 Batt, 8000 copper, or 14000 ceramic. Then polish with 100000 PCD grit on your Batt+.

[Jordi]

Thank you so much for your advice. Perhaps you’re right and I should refine the pre-polishing more. I’ll do some more tests. Cheers!

[Jordi]

Thank you so much, going from 600 to 8,000 on Batt has really given me excellent results!

[Markos]

Nice. Batts are great.

• This reply was modified 3 months, 3 weeks ago by  Markos.

[John Mc Keown]

I agree with the 14000 pre polish, it’s what I tend to use the most.

Cutting I have no set size mesh, big stone use smaller numbers small stones can get away with 1200 to 3000

[Markos]

Spot on.

[brianmaxwell]

Hi Jordi

It will add a bit more to your outlay, but my suggestion would be to get one of the Gearloose Ba5t Laps and some good quality 100 000 diamond grit with oil for polish. I have used this combination since the Ba5t became available on everything I cut including quartz ( despite what Martha Vargas used to say about that ) and have yet to encounter a problem.

My sequence is: – 240 plated diamond from Hong Kong for rough shaping

sintered 600 brass with oil to set facets

Batt with 8000 ***

Ba5t with 100000 ***

**** all diamond powder with 2 drops of oil -worked in with silicon carbide stick – on 8 inch laps

For both the Batt and Ba5t, I apply just the smallest amount of diamond dust with the point of a toothpick – smear it into two drops of oil near the centre on a slowly rotating lap with the ball of the little finger and gradually work it towards the outside of the lap. Once the surface is covered almost to the outside with an even layer, I then employ the silicon carbide stick over the whole surface. There are lots of videos available showing this process.

Hope this is of some help

Brian in Oz

[Jordi]

Hi Brian, thank you so much for your advice. I just ordered the Bat5lap and I’m looking for some 100,000 grit diamond powder of sufficient quality. I’m going to try what you suggested and see if I get good results. I understand that the Batt lap I’m currently using with 50,000 grit can be used with 8,000 grit without any problem, right? And I would use the Bat5 with 100,000 grit. I also have the silicon carbide stickc to charge the lap correctly, as you indicated. I’m going to try it and I’ll let you know if I’ve improved. Another cutter told me that to polish corundum, I should also try a copper lap and 0-2 micron diamond powder with oil ! What do you think of this?

Thank you very much for your advice, Jordi

[brianmaxwell]

Hi Jodi

I get all my diamond powder from Roy James at Beta Diamond in Anaheim Ca. I have never used copper to polish anything but I have a solid 8-inch copper lap with 8000 diamond and oil that I use to put a prepolish sheen on girdle facets during the shaping process. You are right that you can go to a larger size of diamond on any lap without a problem but the reverse is not possible of course.

As I said, I polish everything with Ba5t and 100 000 diamond so there would never be a reason for me to try any other combination and if I did those two would be way down the list.

Try to use the smallest amount you can of both oil and diamond for best results as this is certainly a case of “less is more”.

This is the third time I have tried to do this reply – so if it doesn’t go this time you will have to wait until tomorrow. It would be useful if when typing a reply you could still see what you are replying to!

Good Luck

Brian in Oz

[Jordi]

Hi Brian in Oz, yesterday I received my Ba5t along with the 8.000 and 100.000 diamonds. The first thing I did was clean my old Batt, which I used with the 50,000 grit, and recharged it to 8.000, then I recut the sapphire directly with the Crystalite 600 and then Batt 8.000. So far, the result is excellent. Tomorrow I’m going to prepare the new Ba5t with 100,000 and do the first final polishing tests. Thanks!

[loydblankenship]

1200 and corundum don’t get along.

[Jordi]

Thank you very much, I will keep that in mind

[Jordi]

You are right !

[brianmaxwell]

Best of luck Jordi. Hoping to hear that everything went well. There have been lots of occasions when I have had to make a few attempts at something new to get results to the standards I set for myself – but each attempt is a learning exercise.

Brian in Oz

[David]

Polishing was one of my greatest challenges when I started faceting. I tried different polishing compounds from serum oxide Mylar toppers, to diamond paste, batt sticks, different lubricants, different polishing laps from copper to a batt lap. I finally figured out how to get a good polish after watching a tutorial on faceting on YouTube by Arya Akhavan. My main problem was using too much polishing compound and lube. I now get fantastic polish routinely. I use a batt lap and I suspect copper would work equally well. I wipe down the surface of the lap with WD40. Then wearing a finger cot I put a dab of 50-60k diamond powder on the tip of the finger cot and smear it into the WD40 film left on the lap. When it is evenly spread I would use a scrap piece of corundum to push the diamond into the lap. This is called charging the lap. Then start polishing. You should only need to dress the lap once with the corundum. I will then occasionally clean the lap with WD40 And add more diamond powder as needed. You might want to try other lubricants like musical instrument valve oil or liquid paraffin. Arya says WD40 is toxic so I mentioned alternatives but I also use finger cots because I don’t like getting messy.

[Jordi]

Hi David, thank you so much for your advice. I’ve also noticed that I need to use very little diamond and oil for a much better polish. I use a procedure practically identical to the one you describe. I mainly use WD40 to clean laps, and to apply the diamond, I use the specific cutting oil “La Jurassienne,” which gives me excellent results. I’m currently in the process of polishing a cobalt sapphire as best as I can for the USFG cutting contest, and my final step will be to use Ba5t with 100,000 diamond. I’ve also realized that I was using too low a speed on my cutting lap, and by increasing the speed (perhaps to around 600 rpm), I’m faster and getting better results. Best regards, Jordi