Best faceting prepolish lap

I often get asked what gives the best pre-polish and final polish in a lap.Well that a very broad question.
The answer is what stone are you cutting.
Sapphire copper 8000 Tin alloy or Type metal with 100,000
CZ same.
Zircon, periodot, Topaz, quartz etc copper 3000 or Zinc then Tin alloy 100,000 or you can get away with 50,000.

But I don't use these laps as I make my special alloy that gives the best prepolish and final polish of all laps Ive ever used.
Its available from Gemcuts or Dazlyn Gems who are my NSW and VIC distributors. So don't go rushing off to China and give us Aussies a fare go.
I also make Copper, Tin alloy and Type metal laps for these companies as there is no one else available to do so.
So Im trying to keep innovative faceting ideas alive in Aus but theres not a lot of financial gain in it for me,just helps keep the bills paid.

Whats your best polishing experience. Id like to here it.

Hi rough2cut,
This topic is a bit like poking a bull ants nest with a stick as I would send anyone selling the multitude of imported laps broke. Any material harder than quartz I use 8000 on a ceramic lap to prepolish and then 100,000 on type metal to polish. That's it. What is worse, I only use two solid copper laps 325 and 1200 and over the years as diamond is added they improve no need to buy new ones! Softer stones such as Apatite I have just left out the ceramic. Of course the ceramic lap has to be mastered but does a great job when it is.
Unfortunately this approach is considered old hat not much profit in it for lap sellers.I learned from a world ranked competition cutter and it worked for him. Commercial cutting where time is the issue is a whole different game no doubt.
Ted

I haven't used a ceramic for years but Im getting Bruce Copper out at Lismore club to test a few laps for me as an independent. he uses the ceramic lap with Frank Dixons Teflon oil and grease mix. I recently told him to try adding boron nitride powder to the mix for increased lubrication.You can get this on Ebay Aus as a makeup addative.
Its like adding the old graphite pencil only six times better.
So far the special alloy over 12 or more stones hasn't produced a scratch according to Bruce. I use it as a split lap with 3000 on the out side track and 100,000 on the inside ring.
In my opinion its the best prepolish of all laps Ive used and hasn't failed to polish anything to a very high nearly final finish on 3000 and best final finish on all but but WA opal.
Nice to here from you on this forum. I can tell you anything I want about laps here without affecting someones elses commercial interests. King Sol is up at Oberon so there will be more chat about sapp soon. That's reminds me. Ive been polishing Madagascan sapp an found a very quick way to polish it on the special alloy.It would work for tin too.

So Ill tell you when thres a few more replies.

All good I'm all for information and innovation as long as its a step forward. I tried an imported polishing lap(which will remain unnamed) for curiosity but found it took 10x as long to polish adjacent facets on quartz than my type metal using 100,000 diamond.Worth remembering it took the US facetors many years to catch up to the Aussie faceting standards when they started the faceting competition.They can't get type metal laps no doubt due to the lead content,and seem more concerned with sellable gymics than skill and technique.
Tried a cosmetic cream instead of the vasaline I mix my diamond with, it was such a good lubricate it stopped the diamond cutting/polishing altogether. Apatite was a polishing challenge yu just got to hold yu tongue at the right angle and have a dash or two of patience. Black spinel was another one looked perfect under light bulb but viewed in sunlight hmm back to the lap.
Apart from laps, perfect polish, is a matter of seeing, needs point light source, the right angle of light and good lenses and no doubt younger eyes help too. We can't do much about the latter. Good luck with your laps I might need a new type metal one in a few years they seem to crystalise in the surface layer with time but I've got a few shaves left yet.

Limited experience here but I've just bought a cabbing machine and have found that a soft lap on the ancient little Hall Junior faceting machine I've had sitting here for ages seems to give a better polish using tin oxide on the things I've tried. The 6-wheeled cabbing machine has a rubber-backed canvas polishing pad that mounts on the side with #14 000 diamond paste supplied. It seems to polish flat faces quite well but hasn't been all that flash on the dome so far - perhaps I just need to apply more paste to the pad?

Whatever, I have just been saving the diamond-charged pad for when I cab something really hard and leaving the #360 flat lap attached to the side instead and polishing on the Hall. Another advantage of the tin is that one quick wipe with your thumb lets you know how the polish is going - the diamond is in greasy base (lanolin?) and you can't be certain of the polish level without getting up and washing with soap and water to remove the grease.

I am glad I bought the Cabking though - all of the stages before polishing are dramtically faster then when I was using the Hall for everything. It is also very much quieter running than the 35-year old clunkers at the club, though the actual grinding of stone is never silent. First couple of cabs on it were a bit wobbly, I had been used to standing in front of the wheel and felt awkward at first but have now gotten used to sitting and it is better.

One thing I do want to do though is cab small - 6-10mm - transparent stones such as garnets, amethyst, smokey and citrine and also star sapphires - would I be better off getting cabbing laps to use on the Hall rather than trying to use the cabbing machine?

I like type metal. It does all,but is a little higher maintainance than most laps and subject to more wear and tear. And yes it builds up a layer eventually needing a skim to restore good polishing. But Im making them different. I cast them then compress them at 400 ton in my press. If you give it a good whack with a hammer it breaks up instead of bending. This closes the grain making a better type metal than others. I also do this to tin making it as good as rolled tin like crystallite and having it alloyed
removes the rippling to a fair extent. Fosskieract you can name that lap here its safe to have your say without the threat of removal as long as its contructive.
Any laps a good lap as long as it keeps you faceting. Not many have mastership over a ceramic lap. I like cutting cabs on my faceting machine. In fact I haven't owned a cabbing unit since I was 10 years old. It takes me about 12 minutes to cut an agate cab 30 x 22 oval.

Hi rough2cut I also tend to do some cab work on my faceting machine.

Its great to cab on a faceting machine. Its clean, comfortable and with the right setup of sanding disc and polishing pads very quick. You don't have to outlay for a full new
machine and wheels etc.

Hey I thought we were talking about faceting. Lefty, start your own cabbing topic.

That's a big call " favourite " lap ! I guess my favourite one would be the one that stays on the machine , as opposed to what might , or has flown out the window . I have many laps I'm trying to work out . Don't think I can judge a lap untill its done quite a few stones . And then ... It's going to depend on what material your cutting . As I'm doing a lot of quartz lately ( something I thought I'd never really cut) but now am enjoying when I can get it to work properly . At the moment I'm running 600 straight to polish . Sometimes it worksrough2cut laps have worked well for me , just a little problem( probably me !) on quartz . Topaz , sapph ... No problem . And fast.

Ive been getting good feedback on my new polishing and prepolish laps. Im also starting to make laps for more lapidary companys. Ive changed the way I do things. now they provide all the materials and I supply the labour and machinery to make the laps. So now Im more a machinist than wholesaler.
I still make the sintered diamond laps as my own product and of course my systems. Ive been acussed of self promotion but I make more money cutting than making laps. I do this as a service to fill a gap in the lapidary community and keep some laps as Aussie made.

http://gemcutters.blogspot.com.au/

Have a look at the blog

Hi rough2cut, we cut sapphire from our mine in the gemfeilds, do you recommend 8000 on a copper lap, and 100,000 on a tin lap, at the moment having a few problems getting supoer fine scratches in the final polish, the are very hard to see, need to keep turning the stone to catch the sratches in the right light using a jewlers loupe, currently using a copper lap with 3000 polish, and a tin lap with 50,000 for the final polish

I have been making laps by annealling an 8 inch copper lap and machining out the centre. i then pour my special alloy in the centre and press it at 300 tonne. this makes it a very compact polishing section ideal for sapphire. You can substitute type metal or tin and pressing is optional. then machine both sections at once to form a rapid sapphire polishing lap. The second part is the special polishing compound I use which is very good. These days its all about the polish more than the laps. I make a special polishing kit and use high speeds of up to 2000 RPM. 8000 prepolish 100,000 final polish.

Thanks rough2cut, have bought 8000 grit for prepolish and 100000 for polish, will be giving that a go soon.

Its not just about diamond size, its more about the things you add to the polish as well as what you are polishing. i make a full flexable kit now and have stopped making polishing compounds in jars. the process needs to be flexible to cover different varieties of gems and different types of laps. By using different mediaumd from wax based to oil based polish i can quicken or slow the polish to suit the stone.