Hi Michael and all
We have had quite a lot of discussion about neodymium magnets for
hunting on Skyrock Cafe. Some of the members there have used that method
for some time. It does work quite well. In have a neo on a monopod stick
with 40 kg pull force. But I was not satisfied with this solution
because the chance to miss that little chondrite or iron is too big when
using just one small magnet, so I desided to make a rake like you have
done. This rake is bit larger and have wheels for easier pull and to
keep the magnets off ground so they won't wear down too much or the duck
tape that protects them.
This is a 3D drawing of my Neo Meteorite catcher... ;o) It's slightly
modified the wheeled rake by using five 4 inch neo magnets with 140 lbs
pull force. That allows me to cover just over 2 feet search area at the
same time.
http://www.swedbird.com/meteorite/met_mag.jpg
Regards
Lasse
Michael Murray skrev:
Hi List,
(This is somewhat of a rehash of information I have posted before)
If the meteorite hunting bug has landed on your shoulder but you think
the area you live in is not the best for finding meteorites, you
should give my hunting method a try. You could be pleasantly
surprised at what you come up with. I went to a local hardware store
a few years back and purchased a shop magnet cane. It has a wooden
handle about 40 inches long with a ring magnet on the bottom that is
sandwiched in between two plates of steel. I also purchased a couple
2" x 2" x 7mm neodymium iron boron sugermagnets which I placed very
carefully side by side on the trailing edge of the bottom steel
plate. Please note: If you attempt this beware, strong magnets like
that can injure your fingers quite easily. Use plenty of caution. I
put the cane in a vise so it could not move before attempting to place
the first magnet on. The second magnet was a bit harder to get into
place until it got close enough to the first one.
I have drug my magnet cane all over the place, mostly wherever there
are gravels. I have not had any of my finds substantiated by
experts. None-the-less I have come up with some very possible
"suspect" stones. Some are what I believe are irons and some stonys.
A couple suspect stonys I found in dirt not gravels. This is what
leaves me to believe that even if you might not think hunting in your
area would be very good, you may still find that the magnet will find
them anyway. The smaller objects falling to earth most likely will not
penetrate very deep into the soil when they hit. Some not at all if
the surface is somewhat hard. Erosion can also expose them over
time. I live in an area where a river cuts its way through the
valley. I have found that the river gravels contain quite a few of
what I term "suspect" stones. I suppose the reason for this is that
in time, due to constant washing from snow runoff and forceful rains,
a lot of small material finds its way into the river, including
meteorites.
It takes a little time spent looking close at local rocks to get to
where you can pick the unusual out from the rest with any certainty.
Of course, if you live in an area with very few rocks, anything you
pick up might be worth investigating.
After I have drug the magnets for a bit, I clean off anything that has
stuck to them into a fine mesh (window) screen sitting down in a gold
pan. I put water in the pan so it covers the material. I then wash
the materials vigorously in order to get rid of the dirt and fines,
which are usually magnetite. Then I screen the material again through
a 1/4" mesh screen. That lets me look at similar sized pieces less
than 1/4" by themselves, and then also those larger than 1/4" that
have been separated by the screen by themselves. I will keep some
water in the gold pan with the smaller material and do what is known
in the gold panning world as a blueberry bounce. That moves the heavy
material to the one side of the pan and lets me see any iron or metal
fairly easily as otherwise those pieces might remain buried under
other lighter weight stones. Then I can pass a strong refrigerator
magnet barely above the rocks and pull out almost all the bigger
magnetite and iron pieces. I place the stuff that that small magnet
collects onto a small paper plate and examine them for possible
suspect stones before tossing them. (kind of like gold panning, you
don't want to throw out a nugget) Then I will drain and let all the
stones in the gold pan dry completely. Once dry, I once again do the
blueberry bounce technique and look over the material closely again
using my low-power m-scope. A hand lens, field microscope, or
illuminated magnifier all work but the low-power microscope has been
the easiest on my vision when used for any length of time. I also
spend time closely examining the rest of the material in the pan
because stonys don't always move with the heavier materials. Once I
find a suspect stone, I pull it out of the pan with plastic tweezers
and place it on a small magnet and put it under my scope for a good
look. Some I recognize to be unique and put them in vials for study
later on, and some I keep for examples of good meteorwrongs. Usually
99.999% are simply earth rocks, although even some of those are quite
interesting.
Not all the suspect stones are small but most I have found are 1/2" or
less. A waste of time you say? Well possibly, but it has been a good
way for me to learn about meteorites. This hobby has helped me also
get interested in learning about other solar bodies as well as the
earth. I have a lot of folks on the Met-List to thank for most of
that type information. As far as meteorites go, I'm not so much into
buying, selling and collecting. I just really enjoy finding them
myself and seeing them up close.
So again, I hope some of you who live in the "not the best place to
hunt meteorites" give this a try. But be extremely careful how you
handle strong magnets. I wouldn't want to see anyone smash a finger
doing this. If you are one of the young enthusiasts in this hobby, I
would have to recommend you don't attempt to add any magnets to the
cane. Use it just like it comes from the store. I did for a while
and still I found some very interesting stones with it.
I have a picture here that shows both my cane and my latest attempt at
a magnet rake. The rake has three 80 mm square x 10 mm thick NDIB
supermagnets on it. If you look at it and wonder why I spaced the
magnets so far apart on this apparatus, suffice it to say I was too
chicken to get them any closer. I may move the two outside ones in
about an inch each at some point. I can tell you, I had a enough fun
trying to separate them when getting ready to put them on this rake.
I wouldn't want to get a body part in between two of them.
Everything was muddy when I last used both these things. It's cold
and freezing here still so I haven't tried washing them off. I
apologize, the picture is not the best. I think if you can zoom in
on the cane by the wheel of the air compressor, you can still make out
the 2 - 2" magnets there side by side on the front edge. Don't look
too close at the rake, its my first attempt.
I must explain too that my hunting method and the use of water are not
highly recommended by others in the world of meteorites. The
magnetism might affect testing the stone later on, and tap water may
cause rust prone stones to rust.
Anyway, best of luck with your hunting, If you find something, share
a picture or two
Mike in CO
BTW, the last four pictures are of my first finds using my home-made
magnet rake. I have used it twice now on some short distance walks.
I believe the "suspect" iron is a match to 5 other pieces I had
previously found with the cane. Most likely a piece separated out of
an octahedrite, as I suspect the others like it that I have are. I
can't wait for warmer weather so I can take it out to more areas.
Pictures of the stones aren't too good as they are taken with a camera
on the m-scope.
<http://i127.photobucket.com/albums/p124/mmurray_02/IMG_0579.jpg>
<http://i127.photobucket.com/albums/p124/mmurray_02/2008_i2.jpg>
<http://i127.photobucket.com/albums/p124/mmurray_02/2008_i1.jpg>
<http://i127.photobucket.com/albums/p124/mmurray_02/2008_s1.jpg>
<http://i127.photobucket.com/albums/p124/mmurray_02/2008_s2.jpg>
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