Rust on Welds

[SeanD]

My one-year-old homemade pans are starting to develop rust on the corner tig welds and the spot welds for the dividers. Most of it is on the outside of the pan. I probably didn't clean up the welds well enough or the right way, but I am where I am. Is there something I can do to get ahead of this now?

Sean

[Haynes Forest Products]

sounds like carbon was introduced into the weld making a less than stainless steel weld. I had that happen when I used SS wire in my mig and the gas wasnt the right type and it rusted slightly. I think the metal that was introduced is going to rust regardless of what you other than gring off and reweld:mad: Live with it

[C.Wilcox]

If it's just surficial on the outside you could probably give it a quick scrub with naval jelly to dissolve the rust, wash the pan real well, dry, and coat with wax to prevent moisture from getting into those spots again. The wax will burn off every year of course, but with a little annual maintenance you can probably keep it at bay.

[wegnerwelding]

When stainless is welded, it loses some of its anticorrosion properties. It needs to be passivated(spelling). A pickling paste will treat it, pulling the nickle back to the surface and returning it to its pre-welded. This is all assuming that it was cleaned with a stainless brush, and welded with the proper process.

[Fred Henderson]

If you used a grinding wheel that wasn't stated to be for SS that will cause it also.

[220 maple]

In the summer of 2000 my father and I hauled the old english tin evaporator to Baltimore, Md. to dads first cousins machine shop. He used the old one to make us a shiney new evaporator. Before he would let us bring it home he found someone who had the ability to passivate the stainless steel. I don't know how passivate works, other than the fact that it does not rust in the welds. I don't know what the evaporator manufactures do to stop rust in the welds I suspect they passivate also?

[TF Maple]

You can read about the process here if you are curious like me. http://www.mmsonline.com/articles/how-to-passivate-stainless-steel-parts

[SeanD]

Thanks for all the responses and the article. The weld was done by pro, so I'm confident the process was good, but the cleaning was all me. I can't specifically remember using a grinder on the welds, but if I did, I probably just used a die grinder or a 4" kicking around the shop.

If I get the rust off the right way and clean it properly with a degreaser, can I use the pickling paste to bring back the anticorrosive properties of the stainless or is that just a one-shot deal right after the weld?

The article mentions cleaning the heat tinting off as well. Is the grinder the only way to do that? How do you get down into the bottom interior corner of the pan?

Thanks again,
Sean

[Haynes Forest Products]

Im still a little confused. If you look at SS sinks they are welded up the sides and corners and then machine ground. I have taken a die grinder and resanded them to clean them up and they dont rust at the welds. If Passivateing coats the SS and weld and its 1/100,000 thick Im sure I removed that with a scrub pad the first week I owned it

[wegnerwelding]

What i understand is that when you weld stainless you are changing the properties of the metal. Passivation restores it to the original composition by drawing the nickle back out.

From my experiences. Keep all grinding supplies that are used for ferrous metals locked up, or put away so not to be used in any way on stainless.

Usually the pickling paste is used right after manufacture, it is actually higly corrosive on ferrous materials. I got some on my steel bench and it rusted pretty bad.

[Haynes Forest Products]

Wegner you better get to welding I was up at Roth's and I didnt see any of your Hydro cups:mad: I was going to buy 10 of them:o

[wegnerwelding]

have 50 made on the table, just need to finish handles.

[Bucket Head]

Chances are, the welds were done right, but they wire brushed the welds right after putting them down with a "regular" steel bristled brush. Small particles of ferrous metal were left behind/impregnated and they rusted soon afterward. I've seen countless "textbook" quality S.S. welds on restaurant and dairy equipment only to be blemished by the rust residue from the wrong brush. The welds on the handles of my flue pan have this appearance. Whoever originally put them on did a good job, but they did'nt have a S.S. brush.

Steve