After the kettle punch/drill

[EscapeArtistBrewing]

After punching or step-drilling a standard SS kettle, is there a procedure to make the cut more resistant to rust/corrosion? I'm thinking about allowing the new hole to be exposed to an acid solution, like a mini-passivation (citric acid? Just dab acid on the cut surface for a while?). Any subsequent procedure needed (buffing, coating, etc)?

This all assumes the cut surface would even be more subject to rust/corrosion--thoughts or experiences?

 

[AdjunctBrewer]

High quality stainless shouldn't rust even when cut, no special procedures needed, but it doesn't hurt to:

1.) Use a sharp cutting tool with lubricant/coolant
2.) Remove any debri from the cut to prevent trapping moisture
3.) Clean the cut and surrounding area w/ an acid solution like Barkeepers Friend
4.) Allow to air dry and passivate

 

[Agent]

In theory, either welding/soldering separates the wort from the cut. Or the gasket for a weldless fitting.

 

[EscapeArtistBrewing]

In theory, either welding/soldering separates the wort from the cut. Or the gasket for a weldless fitting.

I agree the o-ring would keep the cut surface safe from brew-time exposure. I was thinking about when I clean the vessel, and don't get the hole completely dry after cleaning--not likely, but possible. (I don't have a single spec of rust on any of my equipment surfaces, and want to keep it that way.)

 

[day_trippr]

Interesting question that I didn't consider when I drilled 10 holes in my three Blichmann G1 kettles. I was way more consumed with concern I'd tear one of the holes while banging out slugs with the Greenlee punch, or skid across the kettle while making the pilot holes for the punch bolt. Never even considered passivating the holes.

But...all the holes went in clean as a whistle and no skidding occurred and to this day well over a decade later there's no hint of rust anywhere, perhaps a testimonial to the self-passivating ability of stainless steel - at least as long as one doesn't contaminate the work piece with iron bits from tools used on carbon steel...

Cheers!

 

[Bobby_M]

I've never had clean cut ever rust.