Stainless Pot - Poor Welds, what to Do?

[ferm.adventures]

Hi - Looking for opinions.. I picked up a well used Stainless Steel and there was a line of black tarnish in spots along a line about 1 above the floor of the pot. I cleaned it up a bit with a stainless steel wire brush on a dremel, and I found below. Looks like welds or impurities.. I'm assuming welds with some trapped air or something.

Anyone have any experience with this? Should I just passivate at this point and move on, or attempt to grind it down and smooth it out? I don't care about the appearance but I'm weary that I would just run into more of the same if I sand away more of the steel here. I assume, leaving as will mean this will get difficult to clea, but since it's a boil kettle, it shouldn't matter too much.

 

[Broken Crow]

As best I can tell from the picture, that looks like there was something caustic in the pot that ate into the wall. If there's no sign of a weld on the outside, then all grinding will do is thin out the pot there. Does it make a ring around the entire interior?
As best I can tell from the pic, personal opinion is that your best bet is to find a good welder who can TIG round the whole thing and then passivate once the porosity's filled in, or just get a new pot.

 

[ferm.adventures]

As best I can tell from the picture, that looks like there was something caustic in the pot that ate into the wall. If there's no sign of a weld on the outside, then all grinding will do is thin out the pot there. Does it make a ring around the entire interior?
As best I can tell from the pic, personal opinion is that your best bet is to find a good welder who can TIG round the whole thing and then passivate once the porosity's filled in, or just get a new pot.

Thanks. Yeah, that is the worst section. probably about 5 inches long. There are a couple more spots elsewhere, but at the same height.

I'd get a new pot before going thru the trouble of getting it welded, as I got it cheap, and It's being used as a test platform right now. While it would be a shame to dump a 15 gallon stainless pot, it was essentially a throw in for a bunch of other used equipment that I bought.

 

[IslandLizard]

It's a boil kettle!
Everything going in there will get boiled, and sufficiently.

Small blemishes and some rough spots aren't going to cause infections in your wort, once chilled and transferred to your fermenters.

 

[Broken Crow]

^ Yeah... mostly what IslandLizard said. Everyone's comfort level is different, and while I know it won't infect a beer, I'd be worried about it collecting gunk from one brew and flavouring the next. Personally though, I'd use it for an HLT as is.

 

[IslandLizard]

I'd be worried about it collecting gunk from one brew and flavouring the next.

Such small amounts of "gunk" hiding in a few scratches and pits won't affect your 3-5 gallons of wort/beer at all.

 

[ferm.adventures]

Thanks guys.. Not overly concerned. Already used it as the BK for a BIAB.

There is a lot more opportunity for gunk to build up in the weldless bulkheads I have on it, than those spots. It was really a lot of confusion on my part on what the hell was going on, ergo my thought it was a weld line.

 

[IslandLizard]

Should I just passivate at this point and move on

In a boil kettle, yes!

If it were a fermenter, there might be potential cause for worry, although those pits look very small and not crazy deep. Probably manageable as is, or brush a little deeper, then passivate.

BTW, is there actually a weld at that level? All the way around?
What's in the picture, is that the worst area?

From the closeup it looks like a decent kettle.
Is there a brand on the kettle or something recognizable, like certain handles mounts?

How thick is the stainless, roughly?
Tri-clad bottom?

 

[ferm.adventures]

In a boil kettle, yes!

If it were a fermenter, there might be potential cause for worry, although those pits look very small and not crazy deep. Probably manageable as is, or brush a little deeper, then passivate.

BTW, is there actually a weld at that level? All the way around?
What's in the picture, is that the worst area?

From the closeup it looks like a decent kettle.
Is there a brand on the kettle or something recognizable, like certain handles mounts?

How thick is the stainless, roughly?
Tri-clad bottom?

It's a NB Mega Pot 1.2, so a decent pot. I don't know how the pots are made... if they are somehow punched or welded together from 2 pieces. The exterior certainly doesn't look like any sort of weld, but I was confused why there would be those spots at the same level.

the pic is by far the worst cluster.

Here is a pull back pic and the other spots. It’s barely noticeable to the touch.

 

[MaxStout]

The spots seem to go around at the same height. Makes me think perhaps a mfg glitch in the seam where they press or weld in the tri-clad bottom.

 

[IslandLizard]

The pits/corrosion divots in the 3rd picture (with the thermometer probe) look pretty darn deep, worse than the ones in your original post, unless they were similar and you smoothed them out with the Dremel.

Still, there's plenty of material left for many more years/decades of brewing.

 

[day_trippr]

The Megapot 1.2 does indeed have a tri-clad bottom. I wonder if the basic "outer" pot is a one-piece deep-drawn affair, and the aluminum heat spreader slug and inside SS "liner" are then pressed in and welded in place. That would explain a weld line only evident on the inside...

Cheers!

 

[tld6008]

That is definitely a crappy weld, incomplete fusion and/or slag trapped. I would not grind it down any more, you could test those areas with an awl or sharp pick. If its slag it will likely loosen up and come out, good metal will still be there. Either way it's sterilized during boiling.

 

[odie]

looks like splatters of solder stuck to the sides...

I wouldn't worry too much...annoying yes...a problem? Likely not