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This list digest contains the following message subjects:

1. LapDigest News for Issue No. 34 Thursday 7/24/97
2. NEW: Automatic Cab Grinding Equipment
3. NEW: Saw Sludge
4. RE: Gem & Lapidary Club Directory - Canada
5. BIO: Bill Cordua


Subject: LapDigest News for Issue No. 34 Thursday 7/24/97

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I have updated two Archive files: Contents-33.txt and Index-33.txt. Contents-33.txt is a collection of all Tables of Contents from all issues through #33, and Index-33.txt is an index of all topics through #33. Use Index-33.txt to search for all instances of a single topic, or just to see the broad range of the topics we have covered.

As you will see, it was a 'slow news day'. We had hardly any postings so I took this opportunity to post one on SAW SLUDGE.


Date: Wed, 23 Jul 1997

Subject: NEW: Automatic Cab Grinding Equipment

Has anyone had experience (or own) some type of equipment for automatically grinding cab pre-forms and/or domes?

I've seen a pre-former/dome grinder (dop stick holder) in the Graves' catalog, and some other company's little dop stick holder in some magazine advertisements. Both claim to automatically grind cab pre-forms and domes.
....Do they work?
....Are they worth the money and/or effort?
....Do they save any time over hand grinding?
....What grinding equipment is required (diamond vs carbide) - etc?

I'm also considering making one - if I can come up with a design that works. Any suggestions?

Jim Schnell
Storage Technololgy Corporation
(303) 673-2685
(Ed. Note: For a query like this, I first look at the latest LJ Buyer's Guide. In the 1996 issue (the issue I happened to have at hand), they show one company making Automatic Cabbing Machines: The Addexton Company, PO Box 3171, Auburn, CA 95604. I know that there are others.

Next, I looked in 'LJ INDEX 1947-1991' (another good book to have around)
for an old article on automatic cabbing or making a cabbing machine. Didn't see one which was obvious from the title, but there were several which MIGHT have referred to an automatic cabbing machine, including:
New Lapidary Marvels 48:06:92,
and Williams Cabochon Machine 55:08:248.
Of course, an article directly about automatic cabbing machines may have had one of those 'cute' titles which hides the contents of the paper. You are going to have to check it out yourself - you might get lucky. And if you do, there is a file in the Archives named LJReprints.txt which describes how to get reprints from LJ.

That is all I can add to this topic. Can anyone else add more?) -- hale

-- non-commercial republish permission granted --

Date: Wed, 23 Jul 1997

Subject: NEW: Saw Sludge

One of the first references I remember reading about SAW SLUDGE was by Vince King when he described the problem of Plaster of Paris (PoP) saw particles mixed with Almag; he said it formed an almost homogeneous mass which just would not settle out. Peter Rowe suggested that he pour the oil in double bagged Kraft grocery bags, the whole being supported above a plastic tub. Vince placed a 1/4" mesh circular gravel screen, as used in gold panning, atop a 5 gallon plastic bucket, and placed the bags in that. That setup worked, and in several days much of Almag oil had separated, with the mass of cuttings retaining enough oil to take on the consistency of clay.

My only problem of saw sludge was how to get it out of the saw reservoir without spilling any on hardwood floors. (She doesn’t like it when I spill oil on HER floors!) I solved that by getting a hand pump used to pump kerosene from a can to a stove tank; price at Wal-Marts. about $3.50. That gets the reservoir almost empty, then I hand clean the rest.

About the time LapDigest started, a thread appeared on Rocks-and-Fossils mail list on Saw Sludge . A summary of the messages is given below, with comments. Permission has been obtained from each author whose item is quoted.

Erich started the thread by saying that he had a 24" saw, and had been using a mixture of motor oil and kerosene. He wanted to know what to do with the sludge. Candy said she uses Pella Oil, and just pours dirty oil in a gallon milk container and lets the sludge settle out. Apparently it separates cleanly, so she pours off the good stuff and reuses it. (Without filtering it some way, I would worry about small suspended particles which did not settle out.)

Cleaning it and reusing it! That's great! But this begs the issue of what to do with the remaining sludge. I phoned the Environmental Hazards office in several local cities and communities and put the question to them. The answers varied so widely that my only conclusion is that it depends on where you live, and if you want to know for your community, ask your local Environmental Hazards office.

JR had a different idea. He suggested soaking it all up with kitty litter, but acknowledges that he doesn't know what to do with the oily kitty litter. (I would disposed of it just like sludge.) He uses kitty litter for the final cleanup in the bottom of the saw after hand removing the bulk of the sludge.

John describes filtering the trash from his saw fluid by putting the sludge in small paper bags(doubled) which hold a couple quarts of sludge. He puts them in a container, raised several inches above the bottom by wooden blocks or bricks. In several days, he expects that over half the saw fluid will have separated out.

Then came two rather creative suggestions. First, Mark Case saves the material and burns it in an oil furnace in his workshop in the winter for heat. Next, Derek Levin said that his daughter burns the oil from his sludge, screens the residue and uses the fines for pottery glazing. Apparently, this is the kind of material that potters like to use as a glaze. His sludge comes mainly from cutting quartz-type material, along with some beryl and tourmaline and a few others. He noted that each batch gives different glazing results. And his daughter likes the results she gets.

An interesting and humorous response came from Jim Crowe, who said: "Like other suggesters I recycle most of the liquid. My coolant is Al-Mag. The final solution for the nearly solid residue was accomplished almost by accident. While carrying around a bucketful I noted a hole beneath the garden gate where dogs had been burrowing under in order to assist in fertilizing the plants. I dumped it there which immediately discouraged the trespassers. After a few days the sludge had hardened to a cement-like consistency. The next step would be to dig up the newly formed sedimentary rock, re-cut it and once again make small rocks out of one large one. After all, is that not the purpose of the lapidary pursuit? Unfortunately the hardened sludge is not very colorful. Try putting the residue in a form and make stepping stones from them."

Why would it harden into a concrete like mass? Is there a chemical reaction going on, as in concrete or PoP? Or was it just a matter of the liquid slowly draining out and into the ground, leaving behind just a compacted mass of saw dust and chips? Personally I would vote for the later explanation. And if that is so, then all we have done is to return earthy materials to the earth, along with some oily materials. And with the oily materials, some environmental concerns.

Gary Ogg <> suggests using a commercial french-fry grease strainer. He uses one to strain oil in his deep fryer at home, and used one when he worked in a restaurant to strain the oil in the french-fryer. He also uses a similar technique at work to remove particles from the motor oil that they use in hydraulic pressure testing. Motor oil, being much more viscous than vegetable or cutting oil, strains much more slowly.

Gary says: "First, there is an expensive type of filter that filters and pumps clean oil back into the cooker, but the less expensive unit is a simple gravity filter that works much like a drip coffee filter. There are two parts; the filter and the filter holder. The nominal size is 10 inches. The filter holder is a cone shaped wire frame with two handles and measures 18 inches across at the handles. It fits well in a 5 gal. bucket. The filters are made of heavy paper, and fit down into the wire frame. These filters will trap all but the finest particles and the oil will be clean enough to put back into your saw. When the oil has finished draining from the saw, you can scrape out the remaining sludge and put it in the filter to recover as much oil as possible. And since oil is considered hazardous waste, dispose of the filter and sludge responsibly.

These items are available at restaurant equipment supply businesses. A recent price check found a wide range of prices, so shop around.
Strainer (wire frame) - new - $9.45 to $18.00
- used - about $4.00
Filters (box of 50) - $10.25 to $35.90
The wide range in prices may indicate differences in quality, so I wouldn't buy them sight unseen. The wire frame can be cleaned in your dish washer. (Be sure you clean it well before you use it to clean the oil in your Fry Daddy!)"

That’s about it; if any of you have any other suggestions for cleaning or using or disposing of saw sludge, please write and tell us about it.

-- non-commercial republish permission granted --

Date: Fri, 7/25/97

Subject: RE: Gem & Lapidary Club Directory - Canada

In Issue 32, we gave Club Directories for Australia and the US. Here is a great one for Canada. The Directory is put out by the Rock and Mineral Association of Carada, and the URL is <<>>. If you want to see what a good directory looks like, look at this one!

Date: Wed, 23 Jul 1997

Subject: BIO: Bill Cordua

Hello everyone.
My name is Bill Cordua and I am a professor at the University of
Wisconsin - River Falls. I teach introductory geology, oceanography,
mineralogy, and petrology. I was born and raised INSIDE THE BELTWAY of
Washington, D.C. which explains alot of my quirkiness. I got bit by the
dinosaur bug when I was a kid. On one of our visits to the Smithsonian, my
mom and I wandered into the Hall of Minerals there and I was hooked for
I studied geology at George Washington University, then got a
Masters and PhD from Indiana University. I have been teaching
undergraduates and anyone else who wanted to learn about geology ever
since. I don't do lapidary,as I have too many thumbs to be succcessful.I do
like to hear what people are doing and can answer questions on the
geological and mineralogical nature on gem material. Those questions get me
thinking and curious about many interesting areas of the field.
I give a lot of talks and write a lot for the newsletter of my
local club (The St. Croix Rockhounds). Other newsletters pick up my
articles, which is great. The more people read them, the more worthwhile it
was writing them. I must do a good job, because my club nominated me and
got me admitted to the National Rockhound and Lapidary Hall of Fame in
Murdo South Dakota.I have also published recently in Mineral News and Rocks
and Minerals magazine. I'm working on a state mineralogy for Wisconsin and
hope to see it in print eventually.
You are invited to check out my web page at I've got information on my minerals
of Wisconsin work, courses, a vita,and a geology links list. Glad to be
Best wishes - Bill Cordua

Dr. William S. Cordua Professor of Geology/Mineralogy
315 Ag Science Univ. of Wisconsin - River Falls River Falls, WI 54022 715-425-3139
"Speak to the Earth and it shall teach thee" - Job

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