That's the right basic idea. I tend to lean harder on the IPA and less
on the DI water, but either approach is fine. Washing three times with
soap and water seems excessive; I'd replace that step with something
like "clean as appropriate (technician discretion), visually inspect
for no significant dirt or oil or debris".
After the final alcohol clean, I would blow off the alcohol, not just
let it air dry. This will help remove any dissolved oils that may be
in your IPA, rather than letting them redeposit on the part.
For the hose, it will depend a bit on what you're trying to remove. If
the hose should be relatively clean, and you're mostly worried about
minor dust and handling contamination, I'd flush with IPA, blow dry,
maybe repeat that, then blow some wadded up Kim Wipes or similar
through in both directions until they come out looking clean. Then
flush with IPA and nitrogen twice to ensure the Kim Wipe debris is
entirely gone, then blow off with nitrogen until it doesn't smell.
In all this, you can replace the nitrogen with clean dry air from an
oil-free compressor with an air dryer if you want. Your blowoff gun
will ideally have a final filter on it, such as
https://www.mcmaster.com/blowguns/clean-air-blowguns-6/.
Evan Daniel
On Fri, Oct 8, 2021 at 9:26 AM <willsrw@xxxxxxxxx> wrote:
Hi
I am looking for a bit of advice on cleaning for a hose for N2O. The hose
I’m cleaning is a used to transfer liquid N2O from a large bottle to a much
smaller one.
The hose is 10 feet long, stainless steel braid wrapping over a PTFE core.
Tube ID is 0.25 inch. End fittings female 37 degree flare, ¼ inch (I think
it’s a -4).
With a smaller 12 inch tube I used the same process for cleaning other
oxidizer equipment. Start with mechanical cleaning, three times with soap
and hot water with tap water. Last wash, it was raised thoroughly. Then, I
place the part in an ultrasonic cleaner for 30 minutes at 80 deg C, using
Blue Gold Cleaner and deionized water. Afterwards, it goes into a hot raise
bath. Raise water is distilled water. Next is another distilled water hot
raise bath; then, a cold raise bath. Finally, the part is soaked in a bath
of 100% isopropyl alcohol. Part is removed an let dry. Dries until I can no
longer smell the alcohol. After second mechanical cleaning, nitrite gloves
used during all handling. Parts not directly assembled are double bagged
with date.
What should I do with a 10 foot hose? One thought is to put isopropyl
alcohol in it and vigorously shake. Then drain and blow with bottled
nitrogen until you can’t smell it anymore.
Any suggestions will be appreciated.
Thanks,
Rick Wills
Huber Heights, Ohio