tank modification

[wibauxman]

I'm planning on modifing 3, 4 1/2 bbl single wall SS conical fermenters into Bright Beer tanks. I need to put in a carbonating stone. Does anyone have the specs on how to do this, where to get the stone, and any other helpful information? I have a good SS welder willing to do the work, but has never done this before. I'm trying to get the info for him.

Thanks for your help,

Jim Devine
Beaver Creek Brewery
Wibaux, MT

[lhall]

I would just weld a 1-1/" triclamp ferrule to a spot near the side door of the conical, and attach a carb stone to the ferrule. Your welder should be able to polish the inside weld from the doorway easy enough.

You can order both through someone like GW Kent. You can also get stainless TC fittings at mcmaster-carr.

[BrewinLou]

Make sure there is an inert gas in the tank while the welding is going on. This helps prevent oxygen from getting into the weld.

[BeersmithMT]

Jim,

Wow, opening a brewery in Wibaux! Welcome to the Montana brewing community! It sounds like you might have the former brewing equipment from Miles City. We do have a state association you should consider joining. In fact, our next meeting is Nov 8th in Butte. Email me at brewers@blackfootriverbrewing.com if you're interested.

As far as modifying your tanks to be brights: Linus is on the money (as usual). You can order a 1.5" tri-clamp stainless ferrule from GW Kent (or another supplier) and a 1.5" carb. stone assembly. All you need is a sanitary welder to install the ferrule into the lower straight-wall portion of the tank. If those tanks did not have pressure relief valves (PRV) previously installed, you will want to outfit them with those too. 15PSI is the norm, but will depend on the ratings of your tanks.

BrewinLou also makes a very good point that a non-sanitary welder might overlook. Oxygen must be kept off the metal surface while welding or else the steel will oxidize and a sanitary weld will be near impossible. An inert gas must be used to "blanket" the area, I believe Argon is the common choice. Our welder normally shields the area to be welded with "dome" made of aluminum foil, feeding Argon into the dome while he welds through a small hole. If your welder doesn't feel comfortable doing it, ask some of your area dairy farmers - they almost always have a good sanitary welding contact.

[dick murton]

As mentioned before - what ever else you do, make sure your vessels are capable of withstanding 15 psi or so, and that you have a pressure relief valve rated suitably, i.e. below the maximum working pressure. Competent suppliers should provide a safe working pressure, which is the maximum safe operating pressure, as well as a maximum test pressure, to gove an indication of the margin of safety.


Cheers

[JoeV]

Sanitary Welding

Make sure your welder actually knows how to make sanitary welds. As mentioned he should use TIG (tungsteen intert gas) welding machine and fill the tank with argon. Beyond that the welds need to be ground down completely smooth. I believe to a 800 grit finish. At any rate if your welder really is qualified to do sanitary welding he should know this already. And make sure all the grinding / wire brush equipment he uses has never been used on carbon (plain) steel...or your weld will rust.

[tsewong73]

Is it really necessary to fill the entire tank with argon? There is a shield of argon gas that is blown out of the cup on the end of the TIG wand that protects the weld from air contamination. Plus, if you fill the tank with argon thereby pushing out all the air, how does the welder breath? I'm asking purely out of curiosity because I've TIG welded stainless before - just not sanitary stainless and not inside of a tank. I'm interested in knowing the tank welding process simply because I'm a former welder. I understand what is necessary for welding sanitary stainless, I've just never done it.

[canyon]

sanitary welding

It is only necessary to purge the entire tank with argon if you are welding from the outside and can't get inside to make a smaller purge area. The argon coming out of the torch only protects the weld surface by the torch. The back of the weld must also be shielded. You can tent the area around the back of the weld and purge this area with inert gas. I often use masking tape and cardboard because it is around and I tent well back from the weld so as not to ignite these flammable materials. Aluminmum foil is also used. For jobs with easy back access sometimes it is worth it to make a good argon diffuser with sintered stainless or really really fine screen and then you can position that and it is argon and time efficient. Or a friend can follow you on the back side (if it is a tight fit they will only see the red glow other wise they need eye shade too).
Be sure any sanitary welding is done by someone who knows how to weld sanitary otherwise you will be very sorry.

[tsewong73]

Understood. Thank you, Canyon, that makes a lot of sense. I wasn't thinking about the thickness of the stainless and the need for shielding on the other side. The stainless I have experience welding wasn't as thin as the sheet stainless used for the tanks, so the thought of shielding the other side of the work never occurred to me. The thinnest stainless material I've ever worked with was like 1/8" and the penetration wasn't deep enough to effect the other side and necessitate an argon shield there.

[gabewilson50]

Canyon is right on. Foil tape and dual argon feed is only really applied when you're welding ss piping and you're welding the outside surface (outside surface is protected by the welding gun argon supply, but the inside surface could result in very unsanitary conditions without the inert gas). We're in the process of doing the same modifications to 9 bbts here, and the trick is to perform the weld on the inside of the tank first, then weld the outside. This makes sure that you already have a clean weld on the inside that will hold up to the heat from the outside weld.

I've looked around all over the place and the only place I've really found carb stones and PRVs was from GW Kent. Does anyone else have any recommendations to look for these items, perhaps some other reps or manufacturers? Not that I have anything against GW, just wanted to see all options available to me before I make a purchase.

[lhall]

You can get carb stones from Zahm-Nagel.

[wibauxman]

Thank you for all your input. I will pass this information on to my welder