***I take no claim of this post as my own info. I found it through google and thought this would be great help for others, so enjoy!!!*****
I recently needed to convert a keg into a brew kettle and while doing it I thought about how many people post questions about how to go about it. I thought it would be nice if I posted how I went about doing it along with some photos showing steps along the way. I realize that this is just one of many ways to go about the task, but this is a starting point and I'm sure others can share their methods as well. My choice requires a few simple tools, and the die grinder can easily be substituted with a Dremel Tool. For what it's worth I had just over an hour in doing this project. That is once I had the tools gathered and such. Also, I'm sorry I don't have pictures of me doing the actual work. I was home alone when I did this.
Note: Please obtain your keg from a legal source. It is not ethical (and may be illegal as well) to pay the deposit on a keg and then just keep it, forfeiting your deposit. The safest way is to get your keg from a reputable dealer, like Sabco. Kegs can often be obtained from scrapyards as well.
Q: How do I get started?
A: The first thing you want to do is gather the tools required for the job.
1.Make sure that you have eye AND ear protection
2.I used a die grinder with a thin cut off wheel to open up the keg
3.An electric hand grinder with a sanding disk to touch up the opening and remove rough edges
4.A 3/8" drill with a 3/4" hole saw** for the bulkhead hole.
**Please note that the instructions with the bulkhead kit say 7/8". I used a 3/4" because a hole saw is not what you would call precise and does move around a bit. By the time you clean the burr from the hole, the bulkhead fits nice and snug. You can also use a step bit (AKA uni bit) for this, but a hole saw will cost much less. I have converted 7 kegs to date and am still using the same hole saw.
5.Also needed but not pictured are a pair of gloves to protect from sharp edges, a file for cleaning up the bulk head hole (or a carbide bit in tour die grinder) and some Teflon tape.
Q: Okay, I have all the tools and I'm ready to go. What's next?
A: Next you will want to relieve any pressure that may still be in your keg. You can do this by putting a towel over the tap connection and pressing the steel ball with a screwdriver to relieve the pressure. This may be a little stinky depending upon how long the swill has been in the bottom of the keg. The towel is needed so you don't get a face full of the foul stuff at the bottom of the keg.
Now make a line around where you want to make your cut.
My hole is about 13" in diameter. Also shown is my die grinder -- you may have your Dremel Tool ready here.
Now, with your tool of choice, start to cut lightly on your line. I was able to steady my hands where the tap would connect and I slowly walked around the keg, cutting lightly and a little deeper each time around. After about 15-20 minutes and one disc change, I was through.
I didn't have much stinky stuff at the bottom.
Now you'll want to take your hand grinder and finish off the opening.
This is a disc with layered sandpaper, which takes off sharp edges and leaves a very nice finish. You can also use sand paper and do it by hand, just make sure to wear some gloves so you don't cut yourself!
Q: What should I do about the old swill at the bottom of the keg?
A: I took a break after finishing off the opening to do a soak with some PBW to clean the inside of the keg. I did it now so I could fill the entire keg for a thorough cleaning and not have to run stinky/stale/funky beer through my new fittings.
Q: So now the keg is all clean and I'm ready for the next step.
A: Now you need to drill the hole for your bulkhead fitting. I marked and punched a spot 3-3/4" up from the bottom of the keg to the center of the bulkhead hole. Just make sure that you don't put it right above one of the vent holes in the bottom ring of the keg. This way fire from your burner won't damage the fitting or the seal.
When drilling with a hole saw, I find that a coating of Pam cooking spray works fine for a lubricant. Drill with a fairly slow drill speed and moderate pressure. You will feel the drill bit, then the hole saw working at the proper speed. It will only take a minute or so to drill the hole as the keg is really thin. Remove any rough edges with a file or a bit in your die grinder or Dremel tool.
Here's the finished hole.
My bulkhead fitting of choice for this is a Zymie's bulkhead fitting and can also be seen at Zymico.
Here's what the kit looks like.
It comes with very good instructions that even I can follow. The picture shows the parts as they will be assembled in the keg. Bulkhead and washer go on the inside, the o-ring and nut go on the outside. There are important instructions about tightening included with the kit. Follow those instructions and your o-ring will not get damaged.
Here's what the bulkhead looks like inside the keg after assembly.
Here's what it looks like on the outside with a ball valve attached.
Make sure you wrap the threads with Teflon tape first to prevent leaks.
Q: Am I ready to brew now?
At this point your keggle is basically complete except for the pick up tube of your choice and a dump tube of your choice. I like to use a Bazooka Tee for the pick up end and just some soldered copper tube to dump into my fermenter. The Bazooka Tee can also be seen at Zymico. I'm sorry I don't have all the detailed instructions on how to make these as I transferred these parts from my existing keggle. Basically the parts are just soldered 1/2" OD copper tube, a couple of 1/2" ID copper elbows and 1/2" male pipe fittings that screw into the bulkhead and ball valve.