# Instruments and Equipment > Builders and Repair >  Processing Raw Abalone Shells for Inlay

## man dough nollij

I picked up some raw paua abalone shells in New Zealand, to fool around with and try some inlay. The shells are small ones (farmed abalone, I believe), about 6" across. I've been playing around with grinding the ugly part off the outside, and cutting them up with a Dremel cut-off wheel. I'm finding that the shells are just too curved to get any flat pieces of any size for inlay. Even a 1"x2" piece has way too much "potato chip" in it to sand flat. Luckily I got a bunch of flat pieces, already polished, too. 

Has anyone worked with raw shells to get abalone for inlay? I wonder if there is some trick to it.

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## Rick Lindstrom

I tried it years ago with some pretty big shells, and believe me- it's way more trouble than it's worth IMHO. And somewhat dangerous to your health as well unless you grind that stuff under water. Think "silicosis" or something like that.

If you persist in this quixotic misadventure, be sure to use a respirator and good ventilation.

Rick

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## Glassweb

Rick has got it right... proceed with extreme caution if you must!

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## sunburst

You need BIG ab shells to get any useful inlay material, and you need wet grinding capability, as mentioned.

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## Rick Turner

Been there, done that...

I got a diamond saw in the late 1960s to to that, and it was really a pain in the butt.  Once I discovered Chuck Erikson, I never looked back.

BTW, Chuck did do the research on the hazards, and it's bad...but not as bad as was once thought.  There was a tale that ab dust was poisonous.  It's not; it's merely really bad for you in other ways; it's like breathing sharp sand.  It's not a bad idea to have a vacuum hose right there under your "bird's mouth" pearl cutting station...with a bit of mesh or sheer panty hose over it so you don't lose small pieces you've just cut.

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## Glassweb

ah yes... so beautiful... yet _so_ deadly...   :Wink:

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## MikeEdgerton

Wasn't part of the abalone/pearl cutting thing attributed to the chemicals they used to clean the shell? This is way back in my memory. I think it came from the button manufacturing industry if I recall (not that you should breathe the stuff anyway).

OK, it was in this thread, assuming it was true and all.

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## JEStanek

Like so much of lutheiry, the materials are bad for you... or at least hazardous.  I'll leave that to the pros and just inflict my damaged playing on the world.  Back when I started my IV mandolin kit I was looking at pearl blanks and laminate sheets to use...  I'm probably just lazy enough to keep all my fingers and lung capacity.

Jamie

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## Mario Proulx

I've tried, too, and came to the same conclusion. The small shell can yield some great dots, and diamonds and squares(guitar stuff...), though! Just don't expect to get large pieces. Save the most colorful parts, and use them as needed, for little stuff, and I bet you'll find better colors than in the large slabs we can buy. Work it wet if you can, also, to eliminate the dust; it may not be poisonous as once thought, but it sure lends to a nasty cough!

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## Spruce

I remember a story way-back-when about a fellow who cut a lot of pearl for Wildwood, Dobro, etc., who woke up one morning with half his body numb...

As in the left half...

He said it felt like someone drew a line from the top of his head to his, _well_, and one half was numb and the other OK...

It was linked up to the pearl cutting somehow, and he got better when he started taking a few precautions....

Does this story ring a bell, Rick??
Up around Arcata, about 25 years ago??

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## Rick Turner

I don't remember that, Bruce, but sounds like a stroke or heart attack.  Pearl dust could certainly mess with your lungs.   I do remember a whole treatise that Chuck did on the toxicity issue, and his conclusion was that it wasn't poisonous, per se, but rather very abrasive to lung tissues.  Whichever way it goes, we shouldn't breath the stuff.

I know that Larry Robinson has hand cut more pearl than all of us here put together.  He uses vacuum extraction right at the bird's mouth and doesn't have a problem.  He's been doing little other than hand cutting pearl and other inlay materials for 30 years now.  I'm more concerned about the fine sawdust and finish dust in the air in my shop than about pearl dust.

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## John Arnold

> I'm more concerned about the fine sawdust and finish dust in the air in my shop than about pearl dust.


Probably the most dangerous to a woodworker is abrasive dust from power sanding. The silicon carbide and aluminum oxide particles that are small enough to float in the air are of a size that enters the lungs and stays there. Silicosis for sure.
Shells are composed primarily of calcium carbonate (lime).
I did make myself sick one time while grinding the bark off the outside of some large red abalone shells.

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## Paul Hostetter

The act of sawing or sanding shell results in a dust that is quicklime (CaO). Quicklime becomes extremely caustic when combined with water, which is what happens when you snuff it up and it goes into your sinuses and down your throat and windpipe and into your lungs. The resulting caustic deposit on these mucus membranes burns them, opening them to bacterial infection if not not just simple inflammation. 

Left in the environment for awhile, CaO absorbs water from the atmosphere and converts back to CaCO3 (calcium carbonate) which is less caustic but still not a great thing in dust form.

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## Capt. E

You might contact Tom Ellis. His Precision Pearl Company does half the inlay for US manufacturers of guitars and mandolins (Taylor, Gibson, Collings among others). I have toured his shop a couple of times and I do believe he processes at least some of the pearl he uses.

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## Paul Kotapish

Portland luthier Eric "Ricco" Meyer, who specializes in custom fittings for violin-family instruments, had a creative way of handling potentially toxic wood, shell, and metal dust in his shop--he wore his CPAP (continuous positive air pressure) mask and ran the machine while the lathe or mill were running. That constant positive air pressure from the CPAP kept the dust away from his nose and mouth while working. 

Clyde Curley wrote a story about it in Strings magazine about eight years ago, but it doesn't seem to be online. I don't know whether Ricco is still working that way or not, but it seemed like an interesting approach.

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## Mario Proulx

The CPAP mask will only be good if he also had a really good filter on it, which is doubtful. Maybe he kept the pump in another room and fed the air via a long hose? At any rate, it doesn't have enough positive pressure to keep out all the nasties, methinks. In the spray booth and for nasty-dusty jobs, I use a pressurized hood unit that is fed pressurized, filtered air from a small turbine in another room; makes all the difference in the world for me, as I'm sensitized to many chemicals. There are smaller, portable versions that clip to your belt, also. Good units aren't cheap($1,000 and up), but neither are lung transplants.

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## Dale Ludewig

I think Tom cuts his pearl under water, iirc.

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## Rick Turner

Paul, great information there.  Thanks...

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## Paul Kotapish

> The CPAP mask will only be good if he also had a really good filter on it, which is doubtful. Maybe he kept the pump in another room and fed the air via a long hose?


I can't remember the details, Mario, but I'll try to dig up that article and repost what I can. I know he dealt with filtration one way or another. Ricco is a pretty savvy guy, and maybe he's found a better way to cope in the intervening years, but I thought it was an interesting approach at the time.

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## Mario Proulx

Sounds like he had it figured out, so he must have found a way to filter the air. It's a great idea, but we do need to consider the quality of the air being fed to us. A positive pressure system is also the only way for us bearded ones to be safe around really bad dust, and for some reason, a lot of luthiers have beards, myself included.

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## sunburst

> ...for some reason, a lot of luthiers have beards, myself included.


Yep, lots of us do. Why?
Once, when asked "why I don't you get a hair cut", I replied "because I don't have to".

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## JEStanek

I'll somewhat hijack on a similar note to post a great funny photo to me.  This is a long time volunteer at the Philly Folk Fest.  He's trying to smooth the mud in our performers parking area so the ground can dry and we can have space to park them.  There were plenty of sulfer reducing bacteria in that clay and it stank of hydrogen sulfide.  I don't know what good his respirator was doing *but he was wearing it*.  

We return to your shell cutting, dust breathing, hazardous posting.

Jamie

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## Rick Turner

Respirators don't work well with beards...

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## MikeEdgerton

> Respirators don't work well with beards...


I spent a few years as the head of the emergency response team in a chemical factory. None of us could have facial hair for that same reason.

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## JEStanek

I usually have a beard but always shave when I have to wear a respirator or SCBA for work.  A respirator over a beard is about as useful as a band-aid on a brain aneurism!

Jamie

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## Paul Hostetter



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## toddjoles

Danger will robinson!  Danger!  Danger!

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## sunburst

...

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## man dough nollij

I can see the benefit of cutting 'em underwater. With that rig, you could cut and grind 'em 300 feet deep!

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## Paul Hostetter

But forget about spraying lacquer down there.

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## Rick Turner

Do dehumidifiers work down there?  Have to ask Henry...

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