Intro: 10$ DIY "Kettle Bell"
The "Kettle Bell" or Russian Kettle is a traditional training instrument developed in Russia and made famous by Pavel Tsatsouline and Valery Fedorenko. Basically it's a big, iron ball with a handle that you swing around, lift and juggle. Kettle Bell workouts are fantastic exercise and are especially good for MMA training.
(For more information on Kettle Bells and what exactly you do with them, I recommend Crossfit.com
and good old Wikipedia.)
Kettle Bells come in several sizes, but are generally measured in poods (1 pood = approximately 36 lbs). A 1 pood kettlebell will run you easily 50-60 dollars. The one in the photo is about 30 lbs, which is plenty to get you started, but you can feel free to add some more weight as you see fit. It cost me about 10 dollars to make (though some materials and tools were free, so prices may vary)
So why not just use a dumbbell? Why does it have to be round? Essentially, the centered/raised position of the handle allows the main pay-load to swing, which means that you have to use your grip strength much more to control it, and it becomes harder to use natural mechanical advantage to lift the weight. Example: doing curls with a dumbbell, there is a point towards the top of the motion where your forearm is pretty much all the way underneath the weight, and you no longer need to engage certain muscles to finish the motion. With a kettle bell, the weight is very difficult to really get "under," so it will make many exercises more difficult and therefore more productive.
This Instructable involves welding, bending and shaping metal at high temperatures and working with concrete. PLEASE follow all safety guidelines, know what you're doing and wear appropriate protection when working with fire, welding gear and metal working tools. Also, exercise with kettlebells can be strenuous. Please consult a physician before using this training aid. A homemade kettlebell is no substitute for a cast-iron one and it is possible for concrete to break off, etc. while using one. Please be aware of these dangers if you choose to proceed. I take no responsibility for misuse of the information provided in this tutorial.
Step 1: Materials and Tools
-1 bag quikrete concrete mix (the "just add water" kind)
-1 dollar store inflatable rubber ball (smaller than a basket ball, ideally)
-2.5 ft. #8 (1inch diameter) Rebar or steel pipe (with rebar you get extra weight, which means less concrete, which means it's more compact and easier to use. At the very least, after you've bent the pipe, fill it with concrete to add weight.)
-1-2 Small weight plates or rebar scraps (depending on how much weight you want to add. I used 5 lbs of rebar scraps tied together with some wire.)
-Packing tape/duct tape
-1 stick/arc welder with safety equipment.
-1 torch/forge setup capable of bending 1 in. rebar or steel pipe.
-2 Buckets (1 for mixing, 1 for holding the mold)
- 1 Hacksaw or other metal-cutting saw.
-An Angle Grinder or Bench grinder would also be useful, but is not entirely necessary to the crafty maker.
Step 2: Cut and Weld Rebar/pipe
Using your hacksaw, cut the rebar into two 10-12 inch sections (sides) and 1 7-10 inch section (top). Notice the side pieces are angled in slightly (about 20 degrees off of 90). Make sure you cut the ends of the top and side pieces at an angle so that they fit together flush. This will greatly improve the strength of your weld.
Weld the side pieces to the top piece and grind off any excess steel. You might want to wrap the corners in tape just in case they're a little rough.
If you chose to go with the forge/torch option, basically just make the handle shape in the above proportions by bending a single long section of rebar. If you used steel pipe, you can probably find corner fittings that will do the job and you can just solder them.
No matter what size you decide to make the handle, and of what material, be sure that the side pieces or 'arms' to extend a few extra inches so that they can have some decent depth when you set them in concrete. Don't worry about getting it exact. Just try to make a handle that feels nice when you hold it (make sure it's big enough to hold in 2 hands as well as one).
Step 3: Prepare the Mold and Add Weight
Take your rubber ball and wrap it liberally in plastic packing tape or duct tape. This is to reinforce the rubber because it will warp significantly when you deflate it and pour in the concrete. You can also use a slurry of plaster of Paris, or plaster-impregnated gauze strips to coat the outside -- these will be more expensive and time consuming, but will product much more aesthetically pleasing results.
Leave two holes about 4 in. apart big enough to put the two arms of our rebar handle through. When it's pretty well covered, cut the holes out with a utility knife and connect them with a slit. The ball will probably deflate a little, but the tape should keep most of it in place.
(see crappy MS Paint image for details)
Once you have the holes set up and the slit in the middle to pour the concrete in you can fill it with water to figure out exactly how much concrete you'll need to mix, but be careful: the rubber is pretty fragile and even with the tape, it will rip easily. You can also get a slightly less exact measurement by calculating the volume of the ball. Most basketballs = 8.5 liters.
To add weight, simply take your plates, scraps, etc. and attach them loosely to the bottom of the handle with wire. It doesn't have to be tight, it just has to be centered between the arms at the bottom and not hanging too far down.
Put the mold in your first bucket and pad it with some newspaper to keep it centered.
Step 4: Suspend, Mix, Pour
Take your handle and your mold and suspend the handle so that it is positioned in the mold. I just took two long pieces of string and tied them to some ceiling beams in my studio and tied them to the corners of the handle until it hung parallel to the ground with the arms low enough down to sit in the mold in the right place.
Dry fit the arms into the holes you have cut in the mold. Make sure the arms stick far enough down into the mold and that they are not so high up that you have a giant handle.
Once it's all positioned, you can mix your concrete. I typically just mix by hand in a big bucket since it's only a small amount. Pour in however much you need to fill your mold. Add water until it is workable, but not watery. it doesn't have to be perfect, but the more water you have the weaker it will be when it dries and the harder it will be to work with.
Pour the concrete into the mold. You can cut the top off of a wide-mouthed 2 liter bottle and use it as a funnel if you don't want to be messy, or you can just pour it in a scoop it out with your hands. The ball will stretch slightly and flatten at the bottom. This is fine. you want it to sit flat on the ground. Once the ball is about full, position it under your suspended handle piece and lower it into the filled mold. Reposition as necessary. Let set and dry for a day or two (or more depending on concrete mix and water ratio)
Step 5: Remove the Mold and Go Wild
When the concrete has dried or at least cured to a reasonable strength, you can cut the mold away. You should have something that vaguely resembles a giant, concrete kettle.
A few additional problems I encountered:
- when you cut the rubber ball, make sure you cut away the part that holds the air valve. The valve pokes out on the inside of the ball and will get stuck in your concrete.
- You many wish to wrap the handle of this thing in some tape or cloth to make it a little less abrasive. You can also use a piece of sturdy steel pipe or bar stock (something smooth and round) for the handle piece and then use the rebar for the side pieces (don't use smooth material for the side pieces though -- the ridges in the rebar are important for preventing the handle from coming loose in the concrete).
- Adding weight is a good idea. It decreases the amount of concrete you need and makes the kettlebell smaller and more similar in form to the cast-iron ones that will run you like 50$
That's it! Hope you've enjoyed it. Go have some fun. Don't get hurt, etc.