Sanitary Welding

catfishblues

catfishblues

Well-Known Member
Joined
Jul 26, 2005
Location
Pfafftown, NC
Alright. I've got a buddy that needs a job done, but I've only got a couple of ideas about how to handle it. Stainless 55gal drum that needs the inside bottom seam welded and ground in order to brew small-batch beer. I guess he got a deal on the drum and doesn't want to drop $600 on a purpose-built drum. Anyway, I'm obviously not sanitary certified, but I'm not sure that is going to matter here. I am concerned with getting it right, though. I don't want bacteria growing because of my welds.

Here's what I was thinking. It's not structural, per-se, as it already has the rolled edge holding it together. I was considering using 316 rod, laying it in the fillet, then washing over with the TIG torch to tie it in at the toe, yet maintain as smooth of a profile as possible. Welding it is going to be a killer, but grinding and polishing might be worse, so I'm trying to cut down on as much of that as I can.

I could also MIG it, but I'm afraid post-weld cleanup would be a budget-killer. I'd also have to pick up a bottle of tri-mix, and I just don't see myself MIGging that much SS in the near future.

So I know we have some badass welders and "drinking enthusiasts" on this board. Has anyone attempted this before? I tried some googling, and couldn't find anything like this out there. Thanks.
 
If you need it I have some 316L filler rod in 3 different sizes.
 
Soldering/brazing is what I was thinking.
Even though something that big is a pita to get heat in and keep it in it to flow, clean-up should be minimal.

Matt
 
Welding it is the easy part. Laying down in that drum and holding your head up is going to be the killer. You're looking at roughly 100 inches of weld, and sugaring through is going to be a big issue
 
I don't think bacteria will grow because of your welds, if it does grow it will be because it was not sanitized correctly. Are you going to pressure test this after welding?
 
Jeff B said:
I don't think bacteria will grow because of your welds, if it does grow it will be because it was not sanitized correctly. Are you going to pressure test this after welding?
Click to expand...


Wasn't planning on it. I guess I could rig up a way to pump a few PSI into it and do the soapy water check, but I don't really have the facilities to do a full-on hydro, and wouldn't know where to take it. Sugaring may be a small issue, but it's not really structural. It's going to see some expansion due to the fact that he'll be boiling in it, but it's mainly to keep it from leaking. From what I gather, on double-crimped barrels with a silicone gasket, the movement will compromise the gasket pretty quickly. I'm guessing he got a killer deal on the barrel and really wants to use it instead of dropping the dough on a ready-made unit. The bacteria concern is due to crevices allowing material to sit around and foster growth.

I'm mainly considering this because it's a friend, and it seems like it will be an interesting project and a challenge to my skills. I like to learn and grow. But if this is a lost cause, I want to back out before I ruin nearly a grand worth of barrels.
 
If he is just using this for a boil kettle then bacteria and perfect sanitation really isnt a concern. If you lay down a decently smooth TIG weld that he can wipe off without it holding too much "junk" in the crevices, he will be OK. If he was wanting this for a fermentation container then it might be a different story.
 
The weld needs to be on the inside, not the outside. Key thing to keep in mind is to remove any crevices that bacteria or other contaminants can get in.

What material is the drum? I doubt its 316L, so a 316L filler rod is useless. The drum is likely 304, so use a 308L rod instead of 316L.

Use a brand new tungsten and nozzle. Use a brand new wheel when sharpening the tungsten. Key thing is, don't use anything that has come in contact with carbon steel.

If you are concerned with the outside of the weld (you should be since its "sanitary"), try purge paste or find a way to purge the back side of the weld to eliminate sugaring of the weld.


For food and beverage contact surfaces, the finish should be at least a 4A finish. You can usually get that with a 220grit sanding pad if you know what you are doing. If not, use a finer grit as it will keep from putting gouges (microscopic) in the metal but will take longer. Don't use a hard grinding disc as with all stainless, its a pretty hard metal and chatter will gouge the finish pretty good and result in a poor finish that isn't sanitary. Use something soft and non woven. 280 and 320 grit scotch bright pads work well. Make sure the main component is aluminum oxide as its made for stainless sanitary work. Aluminum oxide is an anti-microbial agent used in the food industry.

If you need additional info, let me know. I'm a construction manager in the pharmaceutical and food production industry.
 
Food grade sanitary welding is how i make a living. Been doing it for thirty years.
If you can get the drum relayed to me, i will hook you up.
All i ask in return is a six pack from the first batch of :beer:
Later, Paul...
 
Jody Treadway said:
That is an awesome offer right there!
Click to expand...


No kidding!

There's a lot of insight here! I knew somebody here would have some good information for me. Redneckcj5guy, I may end up taking you up on your offer. I'd like to do it myself just so I can say that I did. Another feather to add to my cap. It also serves to justify buying new toys! ;) I figure I can back-purge if I drill a small hole in the outer ring of the crimp and flow argon in there. I'll have to buy a tee, but I've got a couple of regs and hoses I could play with. If I do take you up, though, I'd at least like to be there to watch your technique and maybe lay some metal down myself.

Rockcity, thanks for the finish requirements. I guess a scotch-brite on a 2" or 3" backer would be the easiest way to get in there and deal with it. I've done plenty of SS welding and a little cosmetic polishing, but this is a new sort of challenge for me. I do have a question about your recommendation of 308 vs. 316. My understanding was that (as a general rule) any filler metal of a higher numerical grade should be fine. 316 on 304 shouldn't hurt anything, right? Typically, that's what I have access to. Also, I'm not 100% sure of the grade. It could be 304 or 316. I figured running 316 filler would cover me in either instance.
 
316L filler would be fine. If you don't know the grade of the base metal, then use the 316L. If 316L is all you have, it will work. But, if you have to buy it and the base is 304, then buy the 308 as its cheaper and easier to work with.
 
Gota love the weld guru's on here. Im Damn happy when I lay a bead that doesn't look like a cracked out gorilla laying boogers down.nothing useful to add
 
zombhntr said:
Gota love the weld guru's on here. Im Damn happy when I lay a bead that doesn't look like a cracked out gorilla laying boogers down.nothing useful to add
Click to expand...
<--Is trying to visualize the cracked out gorilla laying boogers down, and its interesting to say the least!
 
Back
Top