Cutting and welding 5 gallon cornelius "corny" kegs to be smaller?

My dad and I are getting all the stuff to start brewing and we're looking into storage vessels right now. Either we're going to have to bottle the beer, and that doesn't sound fun since we only have 1/2 as many bottles as needed for a 5 gallon batch and cleaning nearly 50-16oz bottles doesn't sound fun. Or, need at least one small keg and still bottle part of it.

I can get 5 gallon cornelius kegs for $30-35 shipped. The 2.5 and 3 gallon kegs are at least $100. My question is if it would work to cut the kegs, remove some amount of the metal and TIG weld the two halves back together? In theory, it should work, right? I may need another tank of gas to back purge the tank, or T off my regular tank.

Anyone know offhand what alloy the kegs are? Are they coated with anything, or just plain stainless steel?

Don't bother cutting the keg, just put whatever volume what want in a 5 gallon keg and proceed as normal.

In theory it should work, but why bother? I don't know if your welds will hold pressure (i.e. if it is possible or if you are good enough of a welder to do it).

Kegs are stainless steel. Also, you will need nearly 50-12oz bottles for a 5 gallon batch, not 50-16oz bottles.

your weld would have to be 100% sanitary and pressure tight.

Why not just brew a 5 gallon batch for your 5 gallon keg? Thats what most of us do.

The $30 keg is used and probably has not been refurbed. The $100 kegs should be brand new. A sanitary weld and one that looks good are two different animals. No offense, but if you are asking you probably don't have what it takes.

It can be done. The problem though, unless you know someone that will do it for you for beer or free, it will likely cost you more to have it done than it would cost to buy a new 2.5-3 gallon corny.

Discussed here:
https://www.homebrewtalk.com/f51/2-5g-keg-thoughts-cutting-one-down-16076/#post151334

I know Yuri_rage did one a few years back. I remember him saying it was not easy, as the stainless for the kegs is very very thin.

Welding may not be the right mindset. Brazing with stainless steel silver phosphate rods would be my suggestion.

Years ago worked at a shop that made the Bunn ice tea tanks (make great fermenters) a tight weld that is sanitary it also has to be polished inside. I repaired several cornies some of my own. If you consider cost of gas 308L rods cleaning pads, a used 3gallon corny goes under 100 on ebay...........my.02

Rebel Brewer has brand new 3 gallon kegs for just under $90 (plus shipping). Order two and the shipping per keg is really sweet (somes to about $13 to get two shiped to me). IMO you would be better off getting properly sized kegs than hacking up larger ones.

Also, it only takes about 36-40 pint bottles for a 5 gallon batch (assuming you're actually bottling a full 5 gallons. Most of the time I would get just under 5 gallons for bottles, so I dont think I ever used three cases of the swing top bottles.

My bad on the count, it'd take 40 bottles exactly if I got all 5 gallons, so more like 35-39 realistically.

I was unaware of how thin these kegs were. I was expecting a little thicker metal, like sheet metal on a car. 1/16" tungstens are small, but not small enough for that with limited means of sharpening them and polishing them fine enough.

PurpleJeepXJ, I'm looking for brazing rods but I'm seeing a lot of silver soldering stuff.

Ya your best bet is probably an HVAC distributor but I have been thinking about it and I did not think my suggestion out fully. You would only need 1 maybe 2 rods... They are only sold by the pound which is like 25 rods and that is like $150 for ones to do stainless steel depending on the amount of silver it could be more. I would say just buy 3gal kegs or take your pre-cut kegs to a welding shop and just pay them since they should have everything on hand to Tig weld SS

broadbill said:

Don't bother cutting the keg, just put whatever volume what want in a 5 gallon keg and proceed as normal.

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Second this. As long as it is pressurized with co2 and not air, it should be fine. I use this technique as I am now doing All Grain but can't do a 6 or 7 gal boil on my stove. So, I cut the batch size down and also use ice to help cool, then put it (4 gal batch) in a corny. I also did this for an extract batch where I wanted some in keg, some in bottles.

Looks like modifying or having them modified is out of the question then. I'm not paying $150 for brazing rod for this, no way no how.

The issue isn't having enough to fill a keg, I plan to do 5 gallon batches to keep it easy and not do a bunch of little batches. My concern is keeping it fresh.

As long as there's CO2, it's stable? So let's say I kept a keg outside of the fridge, (like 75-80*F) and ran it through the water dispenser or through a jockey box in the freezer or fridge and dispensed from there? As long as I keep that whole system clean, like flush it with vinegar or sanitizer every now and then, it won't spoil the beer from it being stored warm?

As long as your system is fully flushed with CO2 you're good. Vinegar has uses in the brewery, but you're better off using Starsan (all the acid of a vinegar, none of the byproducts).

If you are going to fill a 5-gallon keg with less than 5 gallons, I would pump CO2 down the "beverage in" line to flush from the bottom. Keep the lid on with the relief valve open and purge for a few minutes.

Once the whole enchilada is sanitized and purged with CO2, it shouldn't mater whether it's kept cold or warm.

dutchoven said:

If you are going to fill a 5-gallon keg with less than 5 gallons, I would pump CO2 down the "beverage in" line to flush from the bottom.

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by "beverage in" you mean "liquid out", i think.

but yes- if you have a sanitary, sealed container, and you fill it with a sanitary liquid, so long as it stays sealed, how would it get spoiled?

improper sanitary technique or damaged seals are the only way contamination can get in.

strat_thru_marshall said:

your weld would have to be 100% sanitary and pressure tight.

Why not just brew a 5 gallon batch for your 5 gallon keg? Thats what most of us do.

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+1 It doesn't have to be a 5 gallon batch to put it in a 5 gallon keg.

Filling the keg with CO2 before filling it should eliminate the need to flush the dip tube with CO2. I typically clean, santize (with StarSan), purge of StarSan using CO2 to push it through the liquid out post and then set it aside (with some CO2 left in it). On fill day, I simply release the oressure and fill with homebrew. Even with virtually zero pressure in the keg, there is still some CO2 in it. Filling from the bottom (as you should always do) means the brew will be covered with CO2 while racking. Then purge of any air that got into the keg and pressurize it.

IMO you don't need to over think this, or make it more complicated. Shaking the keg when it has StarSan in it should get it into every nook and cranny. Let it stay wet long enough to sanitize and you're set.

I store my empty kegs, once cleaned, and sanitized, empty except for some CO2 in them. I purge the StarSan via the liquid out post and a keg jumper line (with one lock on it, not two).

audger said:

by "beverage in" you mean "liquid out", i think.

but yes- if you have a sanitary, sealed container, and you fill it with a sanitary liquid, so long as it stays sealed, how would it get spoiled?

improper sanitary technique or damaged seals are the only way contamination can get in.

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Not to go off on a sterilize vs. sanitize tangent, but all beer is contaminated with something... the question is what it's contaminated with and how much. For most homebrewers with good sanitation practices, the answer is typically "nothing that's going to hurt my beer" or "not enough to have any effect."

But eventually, yes... the beer will spoil. All beer does, even the commercial SIAC's do. (Don't believe me? Go buy an unopened antique beercan and severely diminish its value.) But if your beer regularly spoils before you finish it, you need to either re-examine your sanitation procedures or your selection of friends - not the size of your keg.

mvanwie said:

Not to go off on a sterilize vs. sanitize tangent, but all beer is contaminated with something... the question is what it's contaminated with and how much. For most homebrewers with good sanitation practices, the answer is typically "nothing that's going to hurt my beer" or "not enough to have any effect."

But eventually, yes... the beer will spoil. All beer does, even the commercial SIAC's do. (Don't believe me? Go buy an unopened antique beercan and severely diminish its value.) But if your beer regularly spoils before you finish it, you need to either re-examine your sanitation procedures or your selection of friends - not the size of your keg.

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I was told by a can collector that if you drain the can from a small hole in the bottom the value is left intact. There, you can have your spoiled beer and drink it too.

audger said:

by "beverage in" you mean "liquid out", i think.

but yes- if you have a sanitary, sealed container, and you fill it with a sanitary liquid, so long as it stays sealed, how would it get spoiled?

improper sanitary technique or damaged seals are the only way contamination can get in.

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Good point. I mean, the store keeps beer at room temperature. The cans have the same environment for the beer, a pretty clean vessel with CO2 filling the voids. Somehow I just thought it may compromise the beer from drawing some out... I don't know.

Here is a link to a guy who did up some:
http://www.clearwaterbrewery.com/equipment.html

But the cost of equipment to do it plus labor would put it over $100 each. And the guy who did it said he had a couple of burn throughs with trial and error. And you are starting with a used keg. I bought a new 2.5 gallon as having a 3 gallon keg that I have had for over 15 years. And the older one still looks like new because I do not abuse my equipment. I expect that with routine maintenance of cleaning, changing rings, etc. These kegs will last indefinitely.