Hello Joe,
We have a small sandblaster that seems to have been made from
an airbrush. It was used by our paleontologist to gently clean away
unwanted material from fossils. It runs at 20-30 psi from a
compressed nitrogen tank and uses SiC grit that is probably 400 or
320. The grit sits in the small cup that normally holds paint. It is
very controlable and I have used it to clean feedthroughs and other
ceramic parts that couldn't be baked.
I don't know how much it cost but I would bet it was less
than a few feedthroughs, let alone an entire source flange!
good luck,
Charles
>Hi Tim,
>
> Thanks for the info! We are still trying to figure out how this
>coating got there. We did have to "make" new seats to hold the leads
>of small heater bulbs. The new metal was supposed to be stainless
>steel but maybe it is our problem. The bad thing is that we did not
>notice if the coating happened suddenly or slowly over time.
>
> Our Physics shop has a sand blaster but not a "bead" blaster. I'm
>guessing this would be too rough. It is a large device that you put
>your material in rather than a handheld sprayer. I'm not sure how we
>would protect the parts of the source we did not want blasted. What
>does your bead blaster look like? Any ideas on how much they would
>cost? The bead blasting seems to be the best idea so far.
>
>Joe
>
>> Hi Joe...
>>
>> We have seen a similar buildup at the base of our ion source on our
>> Delta Plus XL, though it was due to a different reason. One of the
>> leads of our filaments had broken, and we used a little clamp to
>> clamp the broken wire back together. The screws in this little clamp
>> were coated with zinc, which is apparently a bad metal to have under
>> vacuum as it degases. The result was a coating similar to yours.
>>
>> We solved the problem by using a bead blaster we have in our lab that
>> we use to clean filaments for thermal mass specs. It did a very nice
>> job of cleaning off the grime without damaging the metal or ceramics.
>>
>> Do you know of anyone with a bead blaster? I would suggest larger
>> round beads (~ 100 micron diameter) at low pressures so as not to be
>> aggressive.
>>
>> Hope this helps...
>>
>> Tim Prokopiuk
>>
>> On 27-Mar-06, at 3:40 PM, Joe Lambert wrote:
>>
>> Hi All,
>>
>> We have a Delta Plus IRMS that is about 5 years old and recently
>> have
>> started having problems with arcing in the source, which is shutting
>> off the
>> high voltage on the machine. We belive the problem has to do with a
>> build-up on the ceramic leads at the base of the source (see attached
>> picture). This build-up may be graphite. A glass-fiber brush seems to
>> remove the material but the brush is too bulky to reach some of the
>> surfaces
>> in tight places. Has anyone seen this happen to their source before
>> or does
>> anyone have any ideas on how to clean this? Acetone and alcohol did not
>> remove anything. The ceramic pieces are not removable and if broken
>> would
>> be bad news. Our last resort is a 5% nitric acid solution, which we are
>> trying to stay away from if possible. If the attached image does not go
>> through, the picture of the dirty ceramics can also be viewed at:
>>
>> http://www.bama.ua.edu/~lambe012/DirtySource.jpg
>>
>> The strange thing is that the rest of the source is almost as clean
>> as if it
>> were brand new.
>>
>> Thanks,
>>
>> Joe Lambert
>>
>>
>> W. Joe Lambert
>> Research Scientist
>> Alabama Stable Isotope Laboratory
>> University of Alabama
>> Geological Sciences
>> 202 Bevill Building
>> 7th Avenue
>> P.O. Box 870338
>> Tuscaloosa, AL 35487-0338
>> Phone: (205) 348-4404
>> Fax: (205) 348-0818
>> email: [log in to unmask]
>> Visit our web-site: http:www.geo.ua.edu/asil
>>
>>
>> -------------------------------------------------
>> Tim Prokopiuk
>> B. Sc. Geology/Technician
>> Saskatchewan Isotope Laboratory
>> Room 241
>> Department of Geological Sciences
>> University of Saskatchewan
>> 114 Science Place
>> Saskatoon, Saskatchewan, Canada
> > S7N 5E2
>> Phone: (306) 966-5712
>> Fax: (306) 966-8593
>> Email: [log in to unmask]
>>
>>
>
>
>W. Joe Lambert
>Research Scientist
>Alabama Stable Isotope Laboratory
>University of Alabama
>Geological Sciences
>202 Bevill Building
>7th Avenue
>P.O. Box 870338
>Tuscaloosa, AL 35487-0338
>Phone: (205) 348-4404
>Fax: (205) 348-0818
>email: [log in to unmask]
>Visit our web-site: http:www.geo.ua.edu/asil
--
Charles Knaack
GeoAnalytical Laboratory
Geology Department
Washington State Univ.
Pullman, WA 99164-2812
(509)335-6742, FAX (509)335-7816
[log in to unmask], [log in to unmask]
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