Stainless Welding, first attempt

CYQK

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Sep 11, 2009
576
beneteau first 42 kenora
Went by my local Praxair dealer yesterday and asked for passivationpaste he looked at me like i was speaking jiberish?
Easy place to buy the stuff???
Thks
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Yea, some guys never heard of pickeling past or passivation acid.

West Marine used to carry Wichinox, which was an overpriced version of that stuff with a little polishing compound mixed in. If you are lucky, you might find some old stock still sitting on the shelf at one of their locations. They seem to have discontinued carrying it. https://www.westmarine.com/buy/wichard--wichinox-stainless-steel-polish--367641 Fishery Supply no longer carries it either.

I now see that Defender seems to have picked up a gel version - https://www.defender.com/product.jsp?id=4693998

The Defender page says that it contains phosphoric acid. I seem to remember that Coca-cola has some of that too. I wonder if Coke would work?
 
Last edited:
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Yes that removes the discoloration. During welding the iron comes to the surface for some stainless (all?) and you need to remove that iron so it does not rust stain.
When you cut or weld stainless, you bring the whole alloy into contact with the surrounding atmosphere. Any ferrous components of the alloy are then free to rust. Passivizing the surface with acid or pickling paste, leaches the ferrous components of the alloy from the surface & leave a boundary layer that is resistant to corrosion. Electro-polishing the surface is another option.

Youtube actually has some good information on stainless & corrosion. This is a decent video to start with -

This one gives a good overview of the different types of SS families that you may run into.
 
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