[Rockhounds] air abrasive units - sticker shock!!!?

[Tim Fisher]

At 07:20 AM 4/20/2008, you wrote:

Living fifteen minutes away from
a superb fossil locality, I've accumulated a modest collection and have
begun looking into how to properly prep them.


Micro air abrasive tools look fabulous, and their versatility is
intriguing, but the $2,000 bare minimum price tag kind of puzzles me. All
this thing does, as far as I can see, is add powdered abrasives to the
air stream. Why the huge price tag? Are there some expensive components
in there, or some advanced technical wizardry? Do you really need to
budget three grand minimum for a complete air abrasive system?

I have 2 used machines, a SS White and a COMCO. Both
needed some TLC but both cost me under $500 used (online). Shop around,
Google is your friend. Cheap units do not have the power or versatility
for fossil prep. They tend to wear out very fast and do little to nothing
to hard fossil matrix (YGWYPF is an axiom to live by, IMO). Most of the
can't even throw powdered dolomite which should be your #1 choice of
media for anything harder than sandstone. They are expensive because it
is extremely difficult to control the delivery of abrasive and air when
you are working at such a fine scale (I have and use a 1 mm nozzle at 90
PSI). {quot}Hobby{quot} (and homemade) abrasive units cannot do so and
wind up spitting gobs of media out that have little to no abrasive power,
or just getting gummed up every 5 seconds. All they can do is coat your
specimen white. 


What are the
options if one wants to get into air abrasive units without spending a
small fortune? Are there cheap units that work as well as the Swam
Blaster and the Comco units? Any DIY possibilities here, or is the system
too complex? Are museums using these multi-thou units?

As above, no there are no cheap alternatives. There
is one homemade model for sale online that I have heard both good and bad
things about. It isn't any less than a used Comco Model 100 anyway, isn't
adjustable, and doesn't appear to be nearly as durable. Most museums use
the SS White models, as they are the most flexible in type of media,
air/media mix, and delivery pressure. Some use the newer COMCO ($$$)
models. I find that I use the COMCO-100 99% of the time because it is
extremely simple to use and works very well. Don't forget to get a full
assortment of nozzles (they are cheap anyway) because you will need to
match the nozzle to the job. 



Tim Fisher 

Ore-ROCK-On! 

Email address at
http://OreRockOn.com




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