passivation technique please

[kimbo]

ok ...it's citric acid ... but in what concentration? and do you flush or allow to dry on the plates? dip the plates or wipe them with it?... thanks again in advance...

[nst6563]

You can find this by searching the forums, and in fact there is a thread or two dedicated to it, but here's what I've had good success with:

%15 Citric Acid solution.
Glass or stainless steel container.
Make sure the container is big enough that you can suspend the plates separated so that the solution can flow freely between the plates.
Heat the solution to approx 140f-160f.
Soak the plates in the heated solution for 35-45 minutes.

Remove plates and rinse thoroughly with distilled water - be sure to get ALL citric acid solution off.

I then hang my plates in a ventilated acrylic container which has 5LPM of O2 blown into it from an oxygen concentrator.

If you don't have access to pure o2, hang them up for a couple days - not around other metals.

It's very important to clean all the citric acid solution from the plates and give them plenty of time to oxidize in the o2.


Read some of the documents in this link -- they should provide all the technical data you should need ;)

http://www.mediafire.com/?bm1jwwwd5z5ht

[kimbo]

thanks for that... did look in faq and did search but did'nt find any info as concise as yours.... thanks again.

[nst6563]

no worries. if you have any more questions fire away. Plenty of us to help out - but those passivation docs I've collected contain some very good information regarding the concentration, temperature, and duration.

Just be sure to wear gloves through the whole process - any contamination whether it be passivation bath leftovers or skin oil will effect the end result.