[meteorite-list] Lessons from the Saw - Cutting Meteorites for Newbies and Curious Onlookers

From: countdeiro at earthlink.net <countdeiro_at_meteoritecentral.com>
Date: Thu, 3 Jun 2010 00:01:03 -0400 (EDT)
Message-ID: <1067984.1275537663881.JavaMail.root_at_wamui-hunyo.atl.sa.earthlink.net>

Thank you, Mike

Count Deiro
IMCA 3536

-----Original Message-----
>From: Matthew Martin <mmartin at meteoritetreasures.com>
>Sent: Jun 2, 2010 7:30 PM
>To: Galactic Stone & Ironworks <meteoritemike at gmail.com>
>Cc: Meteorite List <meteorite-list at meteoritecentral.com>
>Subject: Re: [meteorite-list] Lessons from the Saw - Cutting Meteorites for Newbies and Curious Onlookers
>
>Mike,
>
>That was very nice of you to share your very comprehensive list of
>cutting experiences and lessons learned with the list. I enjoyed
>reading it. Thank you.
>
>Aloha,
>
>Matt
>
>
>
>Quoting Galactic Stone & Ironworks <meteoritemike at gmail.com>:
>
>> Hi Listees, Listoids, and Lurkers!
>>
>> I just past my first anniversary of owning a lapidary saw and I am
>> preparing to cut some unidentified NWA material that is likely a
>> howardite or eucrite. Cutting material like a howardite is very
>> different than cutting something harder like most H-chondrites. This
>> got me to thinking - I often asked the List about various aspects of
>> cutting and polishing, and rarely would I get any useful answers. A
>> small handful of people did contact me in private to give me some
>> pointers, and I would like to thank them again for sharing their
>> wisdom with a rookie cutter. But, in public on the List, you could
>> hear crickets and see tumbleweeds blowing by as I waited for answers.
>> A long-time veteran collector and List member told me the reason is
>> because the skills involved when cutting meteorites are learned
>> through trial and error, and they are akin to "trade secrets" - no
>> successful cutter is going to divulge these techniques because it
>> amounts to helping out the competition.
>>
>> Well, a year later, I am a pretty good cutter - or so I am told by
>> several people who have used my cutting and polishing services. I can
>> make nice even cuts and I can produce a hard polish that is mirror
>> smooth. Recently, I started shopping around my services as cutter to
>> collectors and dealers who don't own saws. In the process of doing
>> so, I had a lot of questions thrown at me - about cutting,
>> preparation, blades, coolants, sanding, polishing, etc.
>>
>> This List has been very gracious to me over the 3 years I have been
>> here, so I wanted to contribute some knowledge back into the List -
>> for the benefit of the newbies, lurkers, and people who are
>> considering whether or not to purchase a saw.
>>
>> First, I want to give a little background on my own cutting, so this
>> will give some context to the tips and pointers I am going to offer
>> below.
>>
>> I use a Lortone Rock Rascal 6-inch lapidary saw. I paid about $300
>> for it. It is now discontinued by Lortone, but they are still
>> available for purchase from some vendors as NOS - New Old Stock. It
>> is the only rock saw I have personally used. I like this saw. I did
>> some research before buying it and I considered several alternatives
>> before deciding on this particular saw. I could have bought a bigger
>> saw and budget was not a constraint - but I went with the 6-inch saw
>> because I don't have much desire (or opportunity) to cut large
>> specimens. The vast majority of the specimens I deal with are about
>> the size of a golf ball, so a 6-inch saw was all I needed.
>>
>> I cut frequently and I have cut several types of material. I have cut
>> some rocks, shells, and other non-meteorite materials, but I will
>> limit my comments to cutting meteorites and tektites.
>>
>> Materials I have cut - every type of OC one can imagine, highly
>> weathered materials, fresh materials, carbonaceous chondrites (several
>> types), mesosiderites, howardites, eucrites, and indochinites.
>>
>> I don't cut irons. It's too labor intensive, time intensive, and it's
>> hard on the equipment. So all of the advice below is geared towards
>> cutting stony-type meteorites and some mesosiderites.
>>
>> DISCLAIMER : I am not claiming to be an expert and these remarks are
>> intended as unsolicited advice for newbies who are curious about
>> cutting or would like to learn more about cutting. I do not claim
>> that my methods and equipment are the best choice on the market. I
>> use what I have and it works for me. Your mileage may vary.
>>
>> SAW and CUTTING TIPS :
>> -------------------------------
>>
>> 1) Bigger saws require bigger blades. Bigger saws make more noise and
>> mess. Get a saw as big as you need - don't buy a saw that can cut a
>> basketball-sized meteorite if you don't have access to such
>> meteorites. Consider what you are going to need to cut and then
>> decide what size saw to get. Keep in mind - half of the saw blade is
>> under the table surface. So, a 6-inch saw has approx. 3 inches of
>> useable cutting surface. This means the biggest meteorite you can
>> properly cut in one pass on a 6-inch saw is about 3 inches in
>> diameter. Replacement blades for larger saws are more expensive -
>> another reason to get the proper size saw.
>>
>> 2) Avoid home improvement tile saws. I call these "Home Depot saws".
>> Yes, they are cheap. And yes, they will cut meteorites. But, the
>> blades are thick and are made for cutting materials like ceramic tile.
>> Loss is not much of a consideration when cutting tiles for your
>> shower surround. But, using that thick tile blade on a meteorite will
>> result in a wide cutting swath of lost material and money. It's
>> similar to swatting a fly with a baseball bat. If you want to lose
>> half of every meteorite you cut, then buy a Home Depot saw. If you
>> want a razor-thin cutting swath and minimal loss, get a true lapidary
>> saw. Further proof of this is to take a look at any successful or
>> experienced cutter - all of them use lapidary saws. (unless they cut
>> irons, and then many use wire or band saws)
>>
>> 3) Don't use tap water as a coolant. Tap water contains chlorine,
>> which will contaminate the material and result in an unstable
>> specimen. Use distilled water only. Distilled water is cheap. You
>> can buy it at Walmart for less than $1 a gallon. With a small 6" saw,
>> a gallon goes a long way. It's well worth the investment. Your
>> specimens will thank you and the people who end up owning those
>> specimens will thank you.
>>
>> 4) A .012" kerf saw is plenty thin. Loss with a .012" blade is very
>> minimal. There are thinner blades available, but some of them will
>> not work with all saws. For example, there are ultra-thin blades that
>> are .006" kerf. These blades are floppy and must be rotated at very
>> high RPM's to maintain their rigidity during cutting. Always check
>> your saw motor speeds and the size of your pulley before using one of
>> these ultra-thin blades. I have tried both, and the .012" is plenty
>> thin for me while still being rigid.
>>
>> 5) Everyone has their own ideas about what type of blade is best. I
>> have tried the CBN blades (cubic boron nitride) that are supposedly
>> designed for meteorites, and I didn't like them. I find that diamond
>> blades cut much better than CBN blades. So, IMO, forget about CBN
>> blades. I use the DiaLaser brand diamond-coated blades and they work
>> very well for me. My next couple of blade purchases will be
>> experimental and I am going to try a sintered Pro-Slicer blade. I
>> will report back in the future about the performance of those blades.
>>
>> 6) You can dry cut a meteorite. I just don't recommend it for the
>> majority of circumstances. If you have a very small and friable
>> specimen that will not react well to getting wet, then you can dry
>> cut. Keep in mind, dry cutting is hard on your blade and will result
>> in a dull blade much faster than wet cutting. But, replacing a $30
>> blade might be a worthwhile trade off if you are cutting something
>> fragile like Orgueil or something very valuable like a lunar or
>> martian. 99% of the time, I cut wet.
>>
>> 7) Don't be in a hurry. Cutting meteorites is not a race. The faster
>> you feed the specimen into the saw, the more likely the blade is to
>> wander, resulting in a crooked or wedged cut. Feed slowly,
>> consistently, and evenly. Cutting in a hurry will only result in poor
>> cuts that require more work later to clean up. It's better not to
>> leave a deep saw mark in the first place, than to spend time sanding
>> it out later - which also results in more loss of material.
>>
>> 8) Don't be afraid to hand cut specimens. I've hand cut hundreds of
>> specimens and have yet to cut my hand or fingers. (*knock on wood*)
>> There are a wide variety of options of available for clamping
>> specimens into a vise or jig that will hold the specimen during
>> cutting. These result in nice straight even cuts. But, all of them
>> have tradeoffs. First, some specimens are odd shaped or small, and
>> they are difficult (or impossible) to clamp into a vise or jig. If
>> you don't have a vise or jig, don't let that stop you from slicing.
>> With practice, it is possible to make straight even cuts by hand. I
>> own a sliding vise for slicing, but I rarely use it. I find it much
>> easier to just hold the specimen in my own hands and I get better
>> feedback during cutting because I can feel the specimen during the
>> cut. I'm not saying that hand cutting is the best way to cut, I'm
>> just saying that it works for me in many situations. Ultimately, the
>> specimen itself may dictate what method is used to cut it.
>>
>> 9) If you do cut by hand - cut slowly and evenly. Do not feed to hard
>> or quickly. Do not force the cut. Let the blade do the work and
>> watch the cutting swath closely, especially in relation to the blade.
>> A thin blade can flex in subtle ways that is not readily apparent, and
>> this can result in an uneven cut. When the blade wanders in this
>> manner, you will end up with slices that have a taper or wedged
>> profile. Also, don't try to cut slices less than 1mm by hand, unless
>> you can live with some breakage. Perhaps I am not experienced enough
>> yet, but when I try to cut super thin slices by hand, it rarely works
>> out well - that is where a feeding mechanism like a vise or jig comes
>> in handy.
>>
>> 10) I guess I shouldn't have to say this, but for the record - wear
>> safety goggles or safety glasses while cutting. Even if you wear
>> eyeglasses, be sure to wear some impact-rated eyewear over those. You
>> will save your eyesight and you will prevent your eyeglasses from
>> being damaged.
>>
>> 11) If your saw doesn't have a light on it, get a "clamp lamp" or
>> similar light fixture and set it up to illuminating the cutting area -
>> with a focus on the blade area. An adjustable desk lamp or shop lamp
>> is good for this. If you want to safely make nice even cuts, you must
>> be able to clearly see what you are cutting. Don't assume your garage
>> that is sufficiently lit to cut plywood is bright enough to do detail
>> cutting on small valuable meteorites - throw more light on the
>> subject.
>>
>> 12) Keep a magnet handy. I have a magnet on the end of a pencil-sized
>> wooden stick. I prop this up on the saw table during cutting and it
>> helps prevent specimens from getting stuck to the blade or falling
>> into the tank. It's also handy to collect crumbs and specks during
>> cutting. If doing the latter, put a tiny ziploc bag over the end of
>> the wand - to easily remove the crumbs later.
>>
>> 13) That little slot in the saw table that the blade passes through is
>> too wide. Get a piece of thin, flat plastic and cut a small slit into
>> it that will barely accomodate the cutting blade. Shape this piece of
>> plastic to fit as a "template" that will drop onto the cutting table
>> and can be removed easily. This will help prevent thin slices and
>> pieces from dropping through the slot in the table and into the murky
>> depths of the coolant tank. This little modification will pay for
>> itself the first time is saves a thin slice of a rare fall from
>> falling into the tank.
>>
>> 14) Let the stone dictate where to cut. The shape, composition, and
>> size of the stone will usually determine where to make the first cut.
>> Carefully examine the stone prior to cutting and have a plan in mind -
>> don't just start cutting willy nilly. Take notice of any fractures in
>> the stone which may effect the cutting - if you cut across or along a
>> fracture, the specimen will often crumble or a slice may break. Take
>> into account the weathering state of the specimen as this may also
>> effect the cutting.
>>
>> 15) Often you will have two choices for cutting a specimen - cutting
>> it in a way which will expose the most surface area on the slices, or
>> cutting it in a way that will produce the most slices. An example is
>> an elongated or thin (or flat) specimen - if you cut it lengthwise
>> along the narrow profile, you will yield pieces with the most surface
>> area, but you will get fewer pieces. If you cut it widthwise across
>> the longest dimension, you will get a loaf of bread type of affair -
>> many pieces, but with less surface area on each. Which route is best
>> is determined by a variety of factors that the cutter decides.
>>
>> 16) Have your oven on at 225-240F in advance of cutting. After
>> cutting, take the specimens and put them directly into the oven
>> without delay. Bake for 4-6 hours minimum, to purge any moisture from
>> cutting. Some people like to chase the water out with alcohol prior
>> to baking, but I have had good results without using alcohol and now I
>> rarely use it.
>>
>> 17) After you are finished cutting, empty the coolant tank
>> immediately, and then spin the blade dry. Keep your saw clean and
>> tidy and don't let gunk build up between cuttings.
>>
>> 18) Saw marks are difficult to avoid and can be laborious to remove.
>> As I said above, cut slowly and evenly and you will avoid deep saw
>> marks. If you do get saw marks, keep some sandpaper handy in various
>> grits from 100-600 - these grits are easiest to find at Wally World or
>> home improvement stores. Start at 100 for deep saw marks on robust
>> specimens, start at 200 or 220 if you have a more friable specimen.
>> Place the sandpaper on a hard, level, flat surface and then place the
>> specimen "face down" onto the sandpaper - press firmly and sand the
>> specimen in a circular motion. Don't press too hard or the specimen
>> may break or chip.
>>
>> 19) If you don't own a lap polisher, keep additional sandpaper handy
>> in grits from 600 to 1500. Jeweler's rouge is also good to keep
>> around - to achieve those hard glassy polishes.
>>
>> 20) If you aren't in the mood, don't cut. If you don't cherish your
>> cutting time and love what you are doing, it will show in the results.
>>
>> That's it for now. I am off to do some more cutting and polishing. :)
>>
>> Best regards and happy cutting!
>>
>> MikeG
>>
>> http://www.galactic-stone.com
>>
>>
>> --
>> ------------------------------------------------------------
>> Mike Gilmer - Galactic Stone & Ironworks Meteorites
>> http://www.galactic-stone.com
>> http://www.facebook.com/galacticstone
>> ------------------------------------------------------------
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Received on Thu 03 Jun 2010 12:01:03 AM PDT