WELDLESS KETTLE CONVERSION

By: Tom Meier

This article will briefly describe how to turn your brewpot or scrap sanke keg into a bona-fide kettle with a spigot.

Unless you are friends with a welder, it is going to cost a mint to get your stainless kettle welded with a threaded coupling, which is the best way to add in a spigot valve. It requires a TIG welder, and considerable skill welding stainless, and also requires the inside of the kettle to be purged with nitrogen, other inert gas, or coated with purge paste to prevent carbide deposits.

I've called several places in Nashville who have welded on other people's pots, and they charge about $25/hour and for a kettle with two full couplings, they quoted 3 hours per kettle. Luckily, there is a way you can do it much cheaper: weldless.

A weldless conversion kit is nothing more than a compression coupling used as a bulkhead fitting, and fits through a hole drilled in the kettle wall. With that said, here is the skinny.

REQUIRED ITEMS:

-Variable Speed Drill

-Titanium or carbide drill bit set

-Uni-bit Step Drill Bit

-WD-40 or cutting oil

-1/2" Male NPT x 3/8" compression coupling with 3/8" compression nut and

SEPARATE ferrule (not the Home Depot kind with unremoveable ferrule)

-Stainless washer that fits tightly over the 3/8" compression threads on the

coupling

-No.10 rubber o-ring (found in the faucet repair section) (buy a few extra,

they are cheap)

-1/2" brass ball valve, 1/2" female NPT ends (non-vented type)

-1/2" MALE NPT x 3/8" ID hose barb fitting

-teflon tape

For diptube:

-piece of 3/8" OD soft copper tubing

-3/8" tubing bender (spring, or mechanical type)

-tubing cutter (or hacksaw in a pinch)

For 'sightglass':

-piece of 3/8" ID polyethylene tubing

-piece of 1/2" copper pipe

-1/2" Male NPT x 3/8" compression coupling with nut (same as above)

-1/2” NPT x 3/8” hosebarb fitting

-No.10 rubber o-ring (found in the faucet repair section)

-teflon tape

WHERE TO BUY THE PARTS:

You can find brass NPT x compression fittings with loose ferrules and nuts for ~$2 at hardware stores like Ace Hardware on Nolensville near Old Hickory, or Hillsboro Hardware. Lowes and Home Depot have couplings, but you have to also buy the separate nuts and ferrules, since the nuts they come with have unremoveable ferrules. O-rings and washers can be found anywhere including Home Depot.

For the stainless freaks out there, all these parts can be stainless steel, it just costs alot more. American Pipe is the distributor for Apollo Ball Valves, and charge about $25 for stainless fullport threaded valves. I think they also carry swagelok fittings, which manufacture stainless compression couplings.

REMOVING LEAD FROM BRASS PARTS:

Sometime before you start, or at least before you brew, you should follow the recommendations on www.howtobrew.com for soaking brass parts in vinegar and hydrogen peroxide to remove the surface lead. Soak all brass parts you are going to use, including valves, couplings, ferrules, and nuts. According to John Palmer this is not really necessary since the amount of lead is very small, but it can’t hurt.

STEP 1: DRILLING

Mark an X on the spot to be drilled. On a keg, you want it to be 1.5" above the weldline on the chime and located 90 degrees off of the handles. Placing it 1.5" off the weld in a keg will leave you room for false bottoms, including full ones and domed styles.

On a regular pot with a footed false bottom, obviously you want it as low as possible, but you want to leave a flat space at least as large as the hexangonal portion on a 1/2"NPTx3/8"compression fitting to get a proper seal.

Once it is marked, its on to the drilling. For drilling stainless you absolutely must have a variable speed drill. I start off with a 1/8" bit. Spray the surface and bit with WD-40. Apply a good amount of pressure, start off with about the amount of pressure you can comfortably apply using the strength of one arm without locking your arm. The pressure is key, but don't jam down on it enough to break the bit in two. At this point, please put on safety glasses, I have broken a bit and embedded it in sheetrock 12 feet away so again, don't use that much pressure.

The best way I have found is to drill as slow as physically possible. I use one hand gripped and dragging on the chuck to retard the drill speed, even with the variable speed drill at lowest speed. You should see chips of steel once the bit gets started into the metal. If you don't, try slowing down more or adding more pressure.

Periodically stop and spray the bit with WD-40 to keep it cool - hot bits will dull quickly. Once you get to the last little bit of metal in the hole (when its about to break through) sometimes the bit grabs and the drill locks up. Back it out and then come back with drill at full speed with light pressure, this usually does the trick.

With a completed hole, it becomes a piece of cake. Use successively larger bits (+1/16" at a time) until you get a hole large enough to put the stepdrill bit in. Spray the stepdrill bit with WD-40 and slowly ream the hole out. With each step of the bit, try inserting the 3/8" compression end of the coupling (without nut attached). Once it fits in, the hole is done. Grind smooth with a dremel tool, or sand/file the burrs off.

STEP 2: FITTING UP THE COUPLING

Now that the hole is drilled in the side of the kettle, the threaded part of the 3/8" compression end fits through the hole, with a stainless washer and no.10 o-ring on the outside of the kettle, the washer flush with the hex shoulder on the coupling and the o-ring closest to the kettle wall. On the inside of the keg, the 3/8" compression nut threads on and tightens down the fitting, hand tight is enough to make a seal if you are not using a diptube. Without a diptube, you should leave out the ferrule and just thread on the nut. It should not squeeze the o-ring down so far that it disappears.

STEP 3: ADDING DIPTUBE

Size and fit up a diptube if you need one, use a tubing cutter to cut the correct length and a tubing bender to make the 90 degree bend. The diptube gets a nut, then ferrule, and should be tightened down on the coupling so that the tube doesn't wiggle. If the nut won't go any further, but the diptube still wiggles, try removing the washer from the coupling and retightening. If the diptube gets tightened all the way down, but the coupling is not pressed firmly enough against the outside wall of the kettle to make a seal with the o-ring, add another washer and retighten. Be sure you are satisfied with the dimensions and fit of the diptube before you tighten it up, the ferrule compression fits on the tube and can never be moved again.

STEP 4: VALVE

Thread the 1/2" ball valve onto the NPT side of the coupling at the exterior of the kettle, then thread in the 1/2" NPT x 3/8" hose barb, using teflon tape on all the male threads. If the drain hole in the chime of a keg (the metal ring around the end of the keg) is centered up on the valve, it could overheat the valve when the kettle is fired. Stuff the hole with foil to prevent damage to the valve.

STEP 5: SIGHTGLASS

To make a useful 'sightglass' do everything in Steps 1&2. I recommend drilling the hole about 30 degrees to the right or left of the spigot valve, and as low as possible to be able to read low volumes. Thread a 1/2" brass elbow onto the 1/2" MNPT end of the coupling, rotated vertically, then thread in a 1/2" MNPT x 3/8" ID hose barb fitting (use teflon tape on all threaded connections)

Push the polyethylene tubing over the hosebarb and trim it at the height you need. Slide the copper pipe over the tubing and mark the height it should be cut at. Take the copper pipe off and hacksaw it to the correct length. Use an angle grinder or dremel tool to cut out a window in the pipe the shape of a coffee urn sightglass, a long rectangle with rounded top and bottom. Make sure the window extends down to at least the end of the hose barb so you can measure low levels. Grind or sand the edges smooth.

The copper pipe goes over the tubing and keeps it upright. You can add measured water to the kettle and mark the gallons on the copper pipe with a sharpie pen or grind marks into the metal. The polyethylene is translucent enough to see water levels. At night a pen flashlight set on top of the copper pipe creates an illuminated sightglass.

MORE ADVICE - KEG TOPS

If you get your hands on a scrap sanke keg (Ron Downer with Rocky River sells them for $25), you can easily cut the top out with a 4" angle grinder and a thin cutoff wheel (I like the DeWalt ones). Just use something to mark a circle and grind away. It is best to make a complete circle groove first, and then come back and grind all the way through the metal. Smooth up with a grinding disk and finish deburring with sandpaper or a dremel drum grinder. Be sure and release any pressure before grinding by putting the keg on its side and depressing the ball with a screwdriver.

MORE ADVICE - FALSE BOTTOMS

Various types of false bottoms can be added to your complete kettle or mash tun. The cheapest ($20-30) suitable for mashing are the domed kind (for kegs or pots) or 10" flat kinds (for kegs only). The most expensive ($60) and nicest for a keg being the full size folding false bottom from SABCO. The diptube goes through a hole in whatever false bottom you buy. With a flat 10" false bottom which tends to move around, you can put a hose clamp on the diptube above the false bottom to keep it somewhat held down. With a false bottom used with a weldless keg, you must be careful not to rotate the valve once you start brewing, since this will also rotate the diptube and could lift the false bottom enough so that hops or grains get under it.

MORE ADVICE - O-RINGS:

The o-rings commonly found at hardware stores are buna-n and are not rated for high heat. I have seen them in service for 30 batches with no problems. High temp rated silicon o-rings are available through Grainger (on Charolette).

Hope this helps in your quest for better beer.

Tom Meier