Re: [DIYbio] Re: ultracentrifuge

Upvote/thumbs-up on the last two comments

On Fri, Mar 2, 2012 at 11:25 AM, Phil <philgoetz@gmail.com> wrote:
> 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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--
Nathan McCorkle
Rochester Institute of Technology
College of Science, Biotechnology/Bioinformatics

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