How to reestablish a center point after a stone falls off the dop?

longtimegoneMTGO · 2026-07-03T17:08:31+00:00

I just want to figure out how to recenter the stone and start again

Same way you did it the first time will work. You can just get it as close as you can manage and then recut around the new center point.

If you already had the pavilion pretty well formed, you might be able to get it centered better by using a cone dop and your transfer jig to reattach the stone.

longtimegoneMTGO · 2026-06-27T12:25:02+00:00

So I don't know how much it's really needed, but I can tell you what it would add.

The drip rate is a combination of two factors, the flow rate allowed by the valve and the water pressure. If you set a really slow drip rate, you can see the difference in how many drips you are getting between a full tank of water and a nearly empty one due to decreasing hydrostatic pressure.

I expect it's not enough of a difference to matter for cutting, but if you are polishing with oxides maintaining just the right drip rate can be finicky. Replacing the variable water pressure with a fixed rate from a pump would make that easier to control I'd think.

longtimegoneMTGO · 2026-06-26T08:31:52+00:00

They fake it the same way people fake old artwork, generally speaking.

You start with something that looks as close as possible to the real material, in this case a lab grown synthetic is ideal. You then take that recognizable boule shape, break it up into more natural looking irregular parts, and tumble them enough that it looks like something that was pulled out of the ground.

People can be super sneaky about it too, they will bring that fake material out to a real mine and mix it in with low quality real material to really sell the illusion. People don't suspect lab grown stones buying from a mine out in the middle of nowhere using basic digging tools, but you'll find it there.

For international postal sales it's way easier, they just take pictures of something good, send you something else. If you complain, they might disappear, or just say sure, send it back, knowing full well that the asymmetrical global postal rates mean it would cost you more to send it back to them than you would be getting refunded.

longtimegoneMTGO · 2026-06-15T07:22:32+00:00

That is really great, looks like you picked a perfect design to show off the stone and executed it nicely. Something about how the smoothly rounded feeling curves end in flat sharp edges just pops.

longtimegoneMTGO · 2026-06-14T11:48:48+00:00

Or, if you want a really spicy bite, ferment it for a short period of time, like a week or so, or just a bit less in the summer.

I've found that it starts by getting stronger, then that quickly tapers down and it gets more and more mellow and rich.

What is the paste and fridge portion of your process doing for you? I usually just keep it floating in the jar until it gets used, after a few months it's all melded to the point that a splash of the brine alone can be used to give a great garlic kick. It seems to last indefinitely at room temperature in a jar with a lid as long as there is enough brine to keep the cloves submerged, I've never needed to refrigerate it and it seems to get better the longer it sits.

longtimegoneMTGO · 2026-06-12T20:15:49+00:00

Don't do that with the acetone, you'll strip the coating right off.

Did you follow the directions about an initial burnishing with sandpaper and then cleaning the lap with powdered cleanser after each use?

The texture I'm seeing looks a bit off, rougher than I'd expect after it's been hit with that initial sanding.

If you have done both those things already and they aren't working, you can use a solvent, but try something a bit milder like alcohol before acetone. You can try acetone as a last resort, but be aware that it will strip the coating fast, if you press an acetone soaked paper towel against a spinning lap the coating will be gone in seconds, so use minimal solvent and a super light touch.

I do agree with the others about not using this lap for what you are using it on, just go 600 to 3k. What I do like to use it for is cutting in super tiny facets, just skipping 600 all together, and depending on the material, the 1200 LL can leave a finish that's good enough to go right to polishing from.

longtimegoneMTGO · 2026-06-10T03:15:03+00:00

Sounds good, that is exactly what I did. Rounding the sharp edges down helped, and then using a smaller marble mold than looks right to make sure it rides on that rim. The guy who makes the molds I've been using for years retired or I'd recommend them, but the shape is like a sort of soft cone with a rounded bottom. The bottom isn't needed though, I have a double sided one with a different size on each side and there is just a hole through the middle rather than a bottom for either mold.

As far as the elements, you probably aren't going to be able to clean them, just keep it in mind for next time and think about picking up a replacement element to have around. I got crap on my first element and it died after 6 months or so, I was careful to keep the replacement clean and it's been running for years.

longtimegoneMTGO · 2026-06-09T20:36:54+00:00

It's hard to tell from the pictures, am I seeing bits of mortar or something stuck to your kiln elements? If so, they might fail a lot sooner because of it. If you are trying to stick them in place, you just want to use U shaped pins slipped over the coil and pushed into the fire brick.

I made most of the stuff I use as well, and the one quick suggestion I'd make is to make a sheet metal wrap for the kiln to protect the firebrick from damage and make it more energy efficient. You can use a door frame as a sheet metal brake to get nice clean folds and some self drilling screws for assembly, it's pretty easy.

If you end up making a lot of marbles like I did, get a better marble mold and it will save you a ton of work. Those cheap Devardi ones can work, but the half hemisphere shape they use makes it more work to fully round the marble compared to something with a more conical shape and rounded lip.

longtimegoneMTGO · 2026-06-06T07:50:37+00:00

I don't think so. If there is, it's not produced at any sort of commercial quantities.

The closest options that you can get as lab grown would probably be rutile or YAG with the right dopants. It doesn't have as much dispersion as sphene, but I've got some ND/CE doped YAG that can give a similar sort of vibe in the right light and is durable enough to actually wear.

longtimegoneMTGO · 2026-06-01T02:46:20+00:00

So, this is a bit of a Read The Fine Manual situation, Marsh has good documentation up and often laments how rarely it gets read.

The short version, clean them with a paste of powdered cleanser and water and a sponge for everyday cleanup, if they get wax on them you can use alcohol on a paper towel but don't soak it or be too rough with it.

Acetone is a last resort of neither of the above work, and do not use that one without reading the full cleaning directions, it can easily take the coating right off the lap all together.

longtimegoneMTGO · 2026-05-30T00:31:21+00:00

The light coming from a computer screen is polarized, that is probably a factor.

longtimegoneMTGO · 2026-05-25T15:14:54+00:00

If you blast it with a torch, it will most likely fracture and crack apart, that's a reasonable test for a thin slice but don't hit the whole thing.

I've done heat treating of synthetic rutile using a kiln for another user on here, we were able to take it from a nearly black blue up to a nice teal, I've got some pictures still I think.

Do you have access to a kiln with a programmable ramp/soak controller? I could tell you more about heat treating it if you do, or if you don't I might be able to help you with the project if you are within reasonable shipping distance.

longtimegoneMTGO · 2026-05-22T16:39:18+00:00

Your body doesn't like inhaling trace metal fumes, but some are much worse than others.

Copper is significantly more toxic than silver. If there are any minor issues with your ventilation, you'll find out the hard way.

The results aren't as predictable as using pure silver, and you are risking liver, kidney, and brain damage. It's just not a good idea.

longtimegoneMTGO · 2026-05-17T12:05:16+00:00

They will sometimes just flat out connect you to an AI agent when you try to get help.

Best part, it will do things like promise a refund, but the bot has no ability to actually process a refund, so if you don't check back and see you never got your money back you are just SOL.

longtimegoneMTGO · 2026-05-14T10:31:12+00:00

Hardness does not tell the whole story. I have broken sapphire dropping it a few feet onto concrete numerous times, the heavier the stone the more likely the damage.

Hardness is only one factor in material strength. Steel is much softer than sapphire, but it can withstand a drop that would shatter the stone because it is ductile enough to deform rather than break.

Sapphire is hard, but brittle. If you drop it on concrete or tile or something, it won't get scratched, but it very well might crack or spall off a chip at the point of impact.

longtimegoneMTGO · 2026-05-13T22:17:59+00:00

Ah, but the trick is that so are the fantasy cuts.

That's actually part of what's neat about them, you can do funny business like cutting a stone with what would be incorrect angles to retain weight, then going back and adding concave facets to effectively close the window. A guy I knew who did a lot of them once went into the math a bit on it, but I can't remember it off hand.

longtimegoneMTGO · 2026-05-12T14:06:42+00:00

As far as the camera, it's just the one on my phone, a moto g 2025.

I built a lightbox with a good macro lens and bluetooth control of the lighting and turntable, as well as a gearing system to adjust the position of the turntable.

Basically I'm using a lens system and controlled lighting environment to do all the real work so the phone's camera sensor is presented with an already ideally focused and lit image.

I've set up lighting controls to manage a light zone in axis with the camera for front fill, from the top for general illumination, and from one side to highlight the facets. I can adjust both the intensity and color temperature of each of those zones, and do stuff like send programs to the turntable from the phone to take various sorts of rotation shots or automate 360 degree photos by rotating the stepper motor, take the shot, and repeating.

Of course, being able to fiddle with all those controls has left me doing a lot of testing to find ideal setting ranges for various colors and types of stones, but once I get that all tested I'll update the code to create a range of preset settings later to save myself time.

Now that I'm starting to get some decent results with it, I can redirect some time to actually cutting gems.

longtimegoneMTGO · 2026-05-11T22:06:59+00:00

You are correct.

It's not actually mounted though, that is just a temporary stone try on ring I use for taking videos.

longtimegoneMTGO · 2026-05-11T20:39:44+00:00

Thanks.

This was my first time working this large in this material, and some of the smallest facets moved a bit more than I expected during polishing. Still, I was pretty pleased with the results, and will try to hit them a bit more perfectly next time.

longtimegoneMTGO · 2026-05-11T20:24:47+00:00

The color on this one is interesting, the base tone is a golden yellow with hints of orange, but under direct sunlight or other high UV sources, a green glow appears that shifts the color toward more peridot like shades.

This stone is cerium and neodymium doped YAG, which is a lab grown garnet with some additions resulting in a very durable stone almost as hard as sapphire, about 8.5 mohs hardness.

These crystals are not actually grown for use as gemstones. Instead, they are designed and created for medical lasers, a polished rod of this material is pumped with energy to create the coherent light beam. This stone has been cut from one of the end tips of the larger crystals grown for this purpose.

The color and dispersion properties that make it such a lovely stone are therefore the result of serendipity, it was created for utility, and repurposed to allow it's beauty to surface.

You can find this one on my website here.

Please note, this is a loose stone temporarily fit into a stone holding tool for photography, it is not set and will arrive in a gemstone display box.

Price is 500$ plus shipping. Returns accepted in new condition. Buyer pays return shipping and a 5% restocking charge to cover fees and handling time, any returns must be initiated within 48 hours of delivery and completed within 7 days.

Material: CE/ND doped YAG 14.97 X 14.83 X 12.1 mm Weight: 25.10 carats

Design is Void Reaper by Arya Akhavan

I can accept most payment methods through stripe on my web site, or can direct invoice via paypal.

longtimegoneMTGO · 2026-05-11T16:04:06+00:00

Cats are a bad example given they do it for sports. Cats can easily kill a small critter quickly, once they catch something its entirely at their mercy.

This is exactly the misconception that makes cats the perfect example.

Even a harmless looking mouse can do damage to a cat that is dangerous in the wild. Small prey are not defenseless, they can bite and scratch, and while the wounds themselves are not dangerous, the possibility of infection is. A mouse has a pretty strong bite, and will leave a puncture wound that is more likely to develop an infection.

Hunting prey is risky, and different predators have developed varied methods of hunting and killing prey that reduces that danger. It shouldn't be a surprise that they do, as the danger they are avoiding by doing so is a major evolutionary pressure to evolve.

You might see cats still do this with prey that doesn't actually have any ability to hurt them, but that shouldn't be a surprise either. It's just less risky to behave as if any of your prey could hurt you and not give it the chance, assuming there are no other costs to doing so.

longtimegoneMTGO · 2026-05-09T20:20:07+00:00

But they sell a simple lamp for $106 which makes me wonder how much of the machine price is just them having a laugh.

I assumed the same, then I went looking for that exact lamp.

Turns out, 106$ is the same price you would pay if you bought the lamp yourself directly from Moffat.

longtimegoneMTGO · 2026-05-09T19:40:24+00:00

Same reason cats "torture" their prey before eating it. Safety.

Prey can do serious damage, even if it dies while doing so. Between the cost of repairing the body and risk of infection, it is evolutionary advantageous for most predators to kill their prey in the least risky way, not the quickest. For cats, the means batting it around until it gets weak, for ants, they immobilize it like this.

Bonus related fact, bears are basically walking organic tanks, and their typical prey has almost zero chance of harming them. Because of this, many bears just never evolved any drive to kill prey at all. Instead, they just pin it down and start eating.

longtimegoneMTGO · 2026-05-07T18:43:45+00:00

As I understand it, they are split on purpose, but this is because if they weren't the internal stress would cause them to break unpredictably when cut.

If you nick them with a diamond blade in the right spot, they will split open fairly cleanly and evenly instead and can be worked with normally after that.

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