On Mar 1, 2:59 pm, John Griessen <j...@industromatic.com> wrote:
> On 03/01/2012 12:06 PM, Cathal Garvey wrote:
>
> > Because an ultracentrifuge can kill you and is highly prone to explosion if used without training?
>
> Isn't this list about training? I see it going on all the time. We have someone
> researching ultracentrifugation and why not evolve a design? Not me saying
> "Do it this way and you'll be guaranteed safe.", but what guarantees are there
> with anything DIY?
If 100 people build their own ultracentrifuges, and each person has a
1% chance
of accidentally killing someone, there's a 63% chance someone will
die.
If one person in the world gets killed by a homemade centrifuge,
governments around the world will use that as an excuse
to crack down on home biology.
We have representatives
from centrifuge manufacturers inspect all our rotors periodically.
AFAIK there are only 2 methods to ensure your rotors don't break.
Either inspect them regularly with X-ray equipment or some
other imaging technology; or have them manufactured by the
same equipment that has already produced several hundred identical
rotors which are being tested and monitored to know how much
usage the rotors made in this way can handle; and keep a log of
how often you use your rotor, and throw it out when it has been
spun a number of times calculated from that stress-testing data.
There are risks worth taking, but at the present time I doubt that any
DIYer has an experiment planned that requires an ultracentrifuge.
My not-very-educated opinion is that, if an experiment is valuable
enough to justify the risk of using a home-made ultracentrifuge rotor,
it's valuable enough to justify spending $2000 on an ultracentrifuge
rotor.
If you're a mechanical engineer and you know how to build things
out of aluminum or titanium, your opinion is more valuable than mine.
I don't know if it's a good idea to buy a used ultracentrifuge rotor.
On the one hand, the odds are very good that it was thrown out
because it had reached the end of its lifespan as computed from
the vendors' lifespan data, which should leave it enough more spins
for a DIYer who might use it a few times a year. On the other hand,
it could have been thrown out because it failed a rotor inspection.
I would be more interested in a DIY design to build a speedometer
for an Airfuge. The standard Airfuge has no way of measuring how
fast the rotor is spinning; you just measure the air pressure you're
feeding it. There are Airfuge tachometers, but they are rare and
expensive
(fetching about $400 used on ebay). All they are is strobe lights
that flash
off a spinning disc visible thru a window that alternates between
white
and black with each spin of the rotor. (Like the tool you used to set
your timing belt on an old car.) You could probably build something
using LEDs and photoreceptors for $30.
Airfuge rotors are made from aluminum. It would probably be
possible find a shop somewhere in the U.S. to manufacture them.
The design patents have expired, so there is no law to prevent
you from cloning Airfuge rotors at perhaps one-twentieth of the price.
But I don't know how you would ensure the quality of the resulting
rotors.
You certainly don't want to outsource that to China to save a few
bucks.
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