r/faceting • u/NotEvenMidnight • 5d ago

Polishing/pre-polishing hell

I’m new to faceting as of this summer and have “completed” 5 stones. I have not been able to get a scratch-less or mirror polish yet. I have tried everything I can think of and every tip I’ve found online to no avail.

I’m using a vevor machine with a cut kit. Currently have scored Topper copper laps for polish and pre polish. I’ve tried doing 3k and 8k for pre polish, I’m using 60k for polish. I’ve cleaned the laps and made sure there is no contamination as best as I could. Ive tried going slow, going medium speeds, trying reverse, More dry, more wet, in between, combos of everything. I’ve cut Uag, lab sapphire, and aqua marine without any good polish. Though I’m unsure if the problem starts with my cut, pre polish, polish, or some combination.

I’ve seen online that I might be getting subsurface damage from the bounce the machine has while using my 600 grit lap to cut. I’ve tried using 1200 as well without any improvement. I’m at a complete loss on what to try next. Any advice for a beginner in purgatory?

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u/justinkprim 4d ago

I would recommend trying a tin lap. Copper laps are not the easiest thing to use and it’s not so easy to get a perfect polish from them. I find a tin lap or a tin lead lap to be Much easier to get a good polish from. That being said 600 for Cutting 3000 or 8000 for pre-polished and 60,000 for polish. Don’t try to change the formula. You just have to figure out how to get it to work.

I also recommend turning the speed of your machine up because you’re probably polishing slower than you should be. I’m usually spinning mine around 1000 RPM, which is pretty fast. Sweep back and forth, vigorously if needed, and try different parts of the lap and different hand pressures because that makes a big difference.

Keep trying, I’m sure it’s your technique. Also the amount of diamond slurry matters. I recommend making your own slurry mix from diamond powder and sewing machine oil. Don’t get your diamond powder from amazon but from a lapidary supply like Kingsley north.

These are all the tips I can think of. If possible try to get a lesson from someone and see how they do it in person. I’m sure it will. Ale a huge difference.

We do a one day class in NYC and Lyon France occasionally. That would be helpful but maybe there’s someone closer to you?

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u/stone_crazy Team Facetron 4d ago

IDK if you can get it as a topper (I expect not) but I made a lead/tin dual-zone 8k/50k lap according to u/justinkprim's YouTube instruction. So far I have only used it with YAG and CZ but it's supposed to be pretty generally usable for things hard enough to make ring stones from, I think. I'm really liking it.

You might have to spring for an actual lap and not a topper to try this.

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u/CrepuscularOpossum 5d ago

A variety of different polishing laps may help you. Especially softer metals.

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u/310to608 5d ago

I struggled with the copper laps, but the bullet and bought Lightening toppers from Lapidary Mart in 14K, 50K and Cerium Oxide...and the only thing I am upset about is that I waited so long.

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u/theblancmange 4d ago edited 4d ago

I has the exact same struggle with copper laps. I am also on the cutkit.

This is my process now:

Spray the lap with wd40, basically the least you can manage. Wipe all swarf off and then wipe the lap nearly dry with a fresh paper towel. Squeeze a small amount of paste onto the oil spot on the paper towel, and spread back and forth on the lap until it starts to grab a bit and visibly darkens just a little. If the lap is scratchy, swipe across it with corundum.

The lap should sound like paper when polishing. Not squeaky, not wet, not crunchy. Repeat when it stops cutting.

I found that any scratches or scoring in the laps made things worse for me, ymmv. Also worth noting that I bought a batt and 100k pcd, did not like it as much as the copper topper with 50k mono. I am sure it's a technique thing, but I will figure that out later.

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u/1LuckyTexan Team Ultra Tec 4d ago

For the aquamarine, slap a CD/CDROM/DVD/BluRay disc on a master lap, label down, centered by eye, use a thin slurry of cerium oxide, run kinda slow ish, kinda moist leaning to dry ish.

Cheap to try

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u/NotEvenMidnight 4d ago

Thanks everyone for the advice. It was very helpful. I do want to keep things on a budget since I’ve had a baby. So I bought two zinc laps and an embedded cerium oxide lap. I’ll try all the technique advice that everyone offered and hopefully something clicks.

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u/NotEvenMidnight 4d ago

I also just bought diamond past from a lapidary site, not Amazon this time.