Removing heat discoloration on stainless ??
 

Most people know you can remove heat bluing from stainless steel by polishing it. However for years I used to get a used machinery publication that had an advertiser than claimed they could remove the blue coloring electronically. They had a handle that had a small sock on the end that you were supposed to dip in some solution and then rub over the discolored area. The handle had a wire running to it. They made some strong clams on how many feet of weld it could clean per minute :eek:.

Is anyone familiar with this type of system ? Any leads or brand names or comments would be much appreciated. Thank you ~ John Buchtenkirch

Hi John,
Just google electric stainless weld cleaner, you will find heaps.

Interresting.

https://www.youtube.com/watch?v=zXRKVhtQgZU

electro-polishing stainless steel
 

see under "electro-polishing"
also "Acid dip"

In the 70's I made stainless tanks & sinks for film developing.
To get the gold - brown weld marks off we would use Lionel train transformer wet rag with passivation acid backed by copper rod or sheet
Ground transformer to sink other positive wire to copper rod move rag backed by copper along weld worked great

I use a machine made by a company called Cougartron and the results are stunning. It’s very easy to use and the welds are clean but not left with the white staining that pickling paste leaves. There are, however, a few downsides.

1) Initial cost was high - starter kit was around £2.5k from memory.
2) Cleaning fluid is expensive - £100 for 5 litres
3) Carbon brushes are expensive - £135 for 10
4) It struggles to clean the discolouration from hot rolled material, the best results are on cold rolled or polished material.
5) Still creates an acidic steam/fumes during use.
6) Leaves a sticky residue that needs thorough cleaning with hot water afterwards.

Having said all that, we wouldn’t go back to pickling paste as the electronic cleaner is so much quicker and with better cosmetic results. It’s really for commercial shops but there’s no reason why a hobby welder shouldn’t own one, if you want professional looking work.

Here’s a link to Cougartron https://cougartron.com/int/weld-cleaning/

There was a thread about this on a welding forum I'm on.

Several people reported success using 12V power supplies with the positive connected to the work, and the negative connected to a conductive brush, something like https://www.ebay.com/itm/Qty-1-Pure-...B/263542164351. For the cleaning solution, they used 1 part phosphoric acid to 3 parts water.

I've not tried it personally, as I rarely work with stainless, but the results looked impressive.

This is very easy to do with a small transformer, (low voltage). A screwdriver wrapped in fiberglass cloth with the acid is what I'm familiar with.
The use I have seen is to provide FDA compliant welds. Grinding causes places for bacteria to hide more so than the acid cleaning.

Thanks guys, I didn’t even know what name to search for………….. saw the advertisements better than 10 years ago………. memory isn’t 100% anymore. Seems like getting a brush for my tig torch and cleaning chemicals might be the most $ensible way to go. At 71 I’m not really looking to spend a lot of $$$ on something I will not use every day. Every time I weld stainless I think I should know more about this but the new stainless sink Lil Franky & I made for the shop kinda reminds me every time I was my hands thru out the day. Polishing welds on inside corners is frustrating :mad:. ~ John Buchtenkirch
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If you want to get rid of just the weld color, a stainless steel (only) wire brush while the weld is still hot is really good followed by a 3M Scotch-Brite paint stripper wheel when cold.
If it's a better finish you want a 3M Scotch-Brite light de-burring wheel will polish nice but don't try and use it as grinding wheel