Metallurgy Question- my SS keggle has rust in it!

I noticed last night after working on my in process e brewery that the keggle i plan on using for my HLT has rust inside. when the project started i sent the keggle to a weld shop to have about 3 gallons removed from the total volume by cutting a section out and re welding togetherthe rmaining halves. now on the inside of the keggle the areas when they polished and ground the welds clean there are rust deposits. Does anyone know of a way to remove this rust and restore the passive coating?

Hmm I wonder if they didn't protect the weld with backgassing.

Anyway from what I've ready you can go at it with a green scrubby and bar-keepers friend.

http://www.howtobrew.com/appendices/appendixB-1.html

Non metallic grinding disk, flap disk, gator pad, etc on a grinder then some Barkeepers friend to scrub the area and let sit with a paste of it on.

The rust is likely from iron/steel particles that were ground into the surface during the post grinding of the weld. The particles were likely carryover from the grinding a steel weld previously. It happens when the grinding wheel is not cleaned or replaced between jobs.

I'd start with the suggestions above for removing it.

I agree with above. Hit it good with a green scrubby pad, dry it out well and let it sit for a week or so to repassivate. I have some kettes that I bought off ebay and they are not seamless, the sheet was rolled together with a weld all the down the kettles and the bottoms were welded on seperately. I let some water sit in one of them overnight and it rusted at the weld spots. I scrubbed the hell out of the welded areas with a green scrubby and let them sit dry for a while and problem solved.

i scrubbed it out last night with a scotchbrite pad and barkeepers friend and looked at it this morning,, looks like ill have to try it again tonight! any danger in running this for brewing as my hlt with the minimal anout of rust in it?

BrewinBigD said:

...any danger in running this for brewing as my hlt with the minimal anout of rust in it?

Click to expand...

None! Keep hitting it with Bar Keeper's Friend and you will re-passivate the stainless.

conpewter said:

Hmm I wonder if they didn't protect the weld with backgassing.[...]

Click to expand...

I wonder if they used SS wire...

Make a paste from the barkeepers and rub it on thick with the green scrubby. The steel was unpassified from the heat from weldin and being worked. Just gotta work it off with the scrubby. Barkeepers has oxalic acid in it. That's the "secret" ingredient to stopping SS from rusting. Cheers!