site etching 304 stainless 2

[deco0404]

I wonder if anyone could offer a little advice on how to etch 304 in-situ. I need to take a surface replica on a piece of 304 welded to X20 pipe. I know that Vilella's or marbles will do the X20, but the 304 I am a little concerned about. I do a lot of lab based SS so am familiar with 10% Oxalic + 6-9V, just have never done anything like this on site.......it may well be the same as lab based, but I cant figure out how you would put a charge across it

Declan

 

[metengr]

I would suggest you visit the site below. I have also done many a field replication but not too often on austenitic stainless steels. Look at the swab etchants for 304. I would try it in the lab to make sure you have the feel for not over etching

http://www.cartech.com/techarticles.aspx?id=1450

 

[deco0404]

some really useful info there..thanks metengr

 

[EdStainless]

Two wires with clips on the end, a 9V battery, and a cotton ball soaked with oxalic acid. I have done this a few times.

But a swab only reagent is easier. It depends on what details in the structure you want to see.
Make sure that you do it a few times in the lab so you know what to expect.

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