Sanitary welds on stainless

[fromhereon]

I'm looking at MIG welding some ports in an old keg but I'm worried about how sanitary they'll be. Should I back purge the keg for MIG welding and can the weld really be sanitary if done from the outside?

 

[kevink]

You don't need sanitary welds on anything that is not a fermenter or anything that does not touch cooled wort. If you don't back purge, your weld will likely rust on the inside. Unless you are an extremely good/experienced mig welder (which I'm guessing you aren't based on your questions) you will probably not be happy with the results. And yes, welds can be sanitary if done from the outside. That's how kegs are welded when they're made in the first place, but they have the process down. Back purging is required on stainless, but it alone does not make a weld sanitary.

 

[fromhereon]

Thanks for the reply. Maybe sanitary is the wrong word. I just want to make sure there's no nooks and crannies for junk to get stuck.

 

[Sconnie12]

No offense but if you need to ask you shouldn't be welding on it. First, a MIG isn't the right tool. Also getting a good back purge while also getting good penetration is a trail and error thing. You will not get a good weld on your first pass.

 

[fromhereon]

No **** but these are the things I need to know before committing to practicing on certain materials or even buying different equipment.

 

[kevink]

In that case, if you want to learn to weld stainless for brew system construction, you'll need a TIG welder and a second argon regulator for the back purge. Then start practicing! It's not terribly hard, but if you've never TIG welded before, you will have your work cut out for you! You can MIG it, but it will most likely be very ugly and your welds will be imprecise. Not worth it IMO.