Forums Beginner Questions Contaminated Lap?/Over Cutting Facets During Polishing

  • Contaminated Lap?/Over Cutting Facets During Polishing

    Posted by hray on May 23, 2020 at 4:15 am

    I am just getting started with faceting, and have some questions about laps. I suspect my laps might be contaminated as they are very old and I am noticing some deep scratches that aren’t coming out in the polishing stage. I have read that sometimes you can remove contamination by washing the laps off. Is there a certain method to this? How do I avoid contamination in the future? Is it enough to wipe the stone clean before changing to a finer grit? Also, when polishing, do I need a master lap to go under the spectra ultra laps, or can I just put the film on top of my pre-polish lap? Is it advantageous to use a maser lap under a cutting/polishing tin lap?

    When trying to polish a citrine, the more I tried to get the scratches out the more my meets went past their point. Is there always this much cutting that happens during the polishing stage, or is it because I am not using a master under my cerium film? Is it advisable to have the points be just short of meeting in the cutting or pre-polishing stage, so that polishing doesn’t cause them to cut too deep?

    gemmakermz replied 2 years, 10 months ago 10 Members · 42 Replies
  • 42 Replies
  • davidechols

    Member
    May 23, 2020 at 6:31 am

    An old cutter years ago told me to use lava soap and I did and have for many years on both cutting and polishing laps for contamination. Polishing will move meets if done too much. Practice and more stones and polish and meets will get better. I would advise anyone starting to facet not too fret too much about meets but focus on getting the polish right. Good meets with good polish will come after some more stones. In other words take it in stages. Learn machine and cutting, then focus on polishing without worrying too much on perfect meets until you master getting a good polish. It will come together later.

  • Alan Balmer

    Administrator
    May 23, 2020 at 11:53 am

    Too little information. What type of laps are you using for cutting and prepolish? What cutting grits? Spectra Ultralaps are OK though they wear out and may round facets, and should show any contamination by visual inspection. I’d get a master lap. They’re cheap and easy to keep clean.

  • hray

    Member
    May 23, 2020 at 1:44 pm

    @Davidchols, Thank you for this info! As a perfectionist, it is really good for me to hear your advice about not obsessing over meet points as I am first starting out. @alanbalmer, Right now I have a very worn 600 and 1200 crystalite lap. I suspect that the 1600 may be acting more like a 3000 since it is so old, so that was what I was using as a pre-polish. I am considering purchasing a BATT lap and charging with diamond for polishing. Is this preferable to using Ultra laps? Can cerium oxide polish be put on the diamond charged BATT if needed? If you or anyone here has recommendations in regards to grit/brands of cutting and polishing laps that would be helpful as I get started, I would appreciate the advice. Thanks!

  • Frankwood

    Member
    May 23, 2020 at 7:11 pm

    If your going to invest in a new set of laps I would recommend getting a set of 8” laps. Having a much bigger surface area to work with is far better.
    One plain aluminium (Australian spelling) master lap, don’t get a one with the magnetic layer on top, they’re a pain to use. Set of bonded diamond laps, they’re about a millimetre thick and go on the master lap as required.
    Don’t get the ones with the sticky back, as for grits I have 180, 360, 600 and 1200. Two Batt laps, one for 3000 grit and one for 50k diamond powder. Keep them away from each other, every time you handle the 3000 grit lap wash your hands before touching anything else.
    I’ve found diamond will polish anything but Quartz, some guys may be able to polish it but I’ve never had any luck. So I use a hard plastic lap with cerium oxide, having plenty of pressure on the stone seems to work best.
    Have a Darkside lap and a stick of Zirconia for Quartz, but found cerium the best.
    When charging the Batt laps I only use 2 drops of baby oil to mix with the diamond powder, have found Diastik’s slower so don’t use them.
    You will get a lot of advice on the forum as to what oil to use on the Batt laps. Baby oil is perfect for the job, it’s cheap and one bottle lasts a lifetime.
    Hope that covers everything.
    Frank.

  • davidechols

    Member
    May 24, 2020 at 7:53 am

    Unlike Frank I have polished everything with diamond. My quartz competition stones were polished with diamond. The old guy that taught me to use lava soap also said diamond will polish everything. Might not be entirely true but close. I started out using diamond on a tin lap. Batt lap is a harder tin lap and is better. For quartz I cut on 600 topper then 3,000 on batt and finish on a 6″ Matrix with cerium oxide. I have found nothing quicker or better than the Matrix and a small amount of cerium for quartz. Get one other Batt to use with 50,000 diamond for everything else. Two Batts and the Matrix and you will need nothing else for polishing starting out, at least that is what I have found works for me. I have no use for any cutting lap finer than 600. The cheap Chinese toppers work fine for me on a master lap. Get 2 more toppers in 260 and 100 for roughing out the stone. The 100 is only used sparingly and be sure and leave enough for the 260 to remove the 100 grit scratches. Before polishing be sure and remove all scratches with the Batt and 3,000 and your meets will not move at final polish, or at least very little until you learn more. I used those flimsy plastic ultra laps when first starting out and they will work but are much too slow for me. It does not take but a few seconds on a Matrix with cerium in water with an artist brush with a small drip of water after pre-polishing on a 3,000 Batt to polish a quartz stone. Some like those bonded oxide laps for polishing. i have tried them and like the ultra-laps they will work but more slowly than Matrix with cerium. One advantage in using them is less mess but it takes so little cerium on a Matrix to polish there is very little mess.

    While learning always remember to have fun and enjoy. You will have some trial and errors but with practice you will be competing one day. Get some cheap man made quartz and do not fret too much when it does not turn out like you want. Take it off the dop and start another one.

  • Lowjiber

    Member
    May 24, 2020 at 9:36 am

    The “cheap Chinese toppers” that @davidechols refers to above are incredible. A good friend from Australia put me onto them.

    It seems that China has the corner on the market for industrial diamond, making the price about half what one will pay for US toppers. They’re all over eBay. I use both 6″ & 8″ toppers almost exclusively when cutting.

  • hray

    Member
    May 24, 2020 at 3:39 pm

    Thanks Frank, this is so helpful! In addition to washing my hands between laps, do I need to also clean the master lap and the stone somehow? I have been wiping the stone with a damp cloth, but am not sure if that is a thorough enough method.

  • hray

    Member
    May 24, 2020 at 3:40 pm

    David, Thank you so much. I wonder if part of my problem is that the lap I used for a pre-polish wasn’t a fine enough grit. I will definitely purchase some BATTs. Do you charge with diamond powder, spray, or the diastiks? Where do you purchase the Chinese toppers from? I am hoping once I try the lava soap on my old laps they might have some life left in them, but it is good to know if they are past the point of no return (and for the coarser grits) there is a reasonably priced option for replacement.

  • hray

    Member
    May 24, 2020 at 3:41 pm

    Thanks @Lowjiber! I hadn’t thought to look on eBay. Do you have a particular seller you have had good luck with?

  • davidechols

    Member
    May 24, 2020 at 7:09 pm

    https://www.ebay.com/str/thkdiamondtools

    I have been buying from him for years. New toppers need some breaking in. Quartz works fine breaking in but the first few stones will have some scratches. Batt with 3000 will take care of them. For a beginner diasticks would probably be the way to go, easiest to learn how much and technique. I use oil, usually WD40, squirt on paper towel and apply then wipe almost all off then apply loose diamond sparingly and rub in with finger. If use you too much diamond or oil you can try wiping it of with a piece of paper towel and try again. It has been years since I used any of my diasticks but they work pretty much the same. Put some on, spread it around lap then wipe some off. With practice you will learn how much to use and omit wiping off.

  • Frankwood

    Member
    May 24, 2020 at 9:12 pm

    You have to get all the 3000 diamond off the stone and out of the crevices that form in the glue that the stones glued to the dop with.
    I hold the dop vertically with a tissue round it and wash the stone with an artists size brush with that alcohol based liquid you get at the hardware. Have a small stiff brush to clean out the crevices.

    After charging the lap with 3000 grit, just use the outer half of the lap. Initially the stone will pick up a lot of diamond/oil mix, but after a short period the lap surface will become much drier. That’s the sort of surface you want, as it dries further occasionally move the stone into the wet area to pick up more diamond.
    The lap speed I use for 3000 grit on a Batt lap is about 300rpm.

  • hray

    Member
    May 25, 2020 at 4:22 pm

    David and Frank, thank you for all your help with this! I now have a clearer idea of the next steps to take. Thanks!

  • scottwkelley

    Member
    May 26, 2020 at 8:37 am

    Hi, welcome.
    I am a novice becoming a master, lol. I had all these same questions. I started out using my cabbing 8″ flat laps. Used the ultra’s and finally ended up using Lightning Laps from Kingsly North a US company. By the way guys there stuff is better and affordable, you get what you pay for. I use 100 topper to remove material fast, but it has to be large, ( time saver ), 220 topper I use to rough in to 2 mm of the size I want or am to get. From there right to my fine 1200 lap ( meets) from kingsly and I will be getting that 3000 when available. LL makes a cerium topper for $30, well worth it. I use all their laps up to and I have 200k, I am not there yet, but ready, still learning on quartz and cz. How in the heck does one polish corundum?
    Lot of good advice here.
    Thanks to everyone for being here, I am so grateful.

  • Lowjiber

    Member
    May 26, 2020 at 9:07 am

    @scottwkelley… You’ll need to use diamond to polish corundum.

  • scottwkelley

    Member
    May 26, 2020 at 9:20 am

    i get that @Lowjiber. But, i get different results, i get to 8k and after that 50k doesn’t touch it. I was blaming pre polish. i decided to ask, learn and try again. it finally came off the dop, thats when i stopped.

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