A monkey's fist knot uses a base to give it a decent mass, rock, lead, wooden ball, etc. 
I used a cheap toy ball, then gave it a quick incision.

Filled it with lime stone gravel. 

Duct tape in two directions to keep it from leaking.

This experiment is to measure the number of wraps needed to cover the ball completely. 
Fifteen wraps were originally used, but only thirteen in the final iteration.

The calulations for the total length of rope were estimated using a cube of similar dimensions as the ball used. 
I originally started with the blue rope, but forgot to multiply by three for each direction of the wraps. I went back to town and got this rope, which is sold by the kilo and not length. 

Setting up the jig to hold the weighted ball while I worked with over 100 feet of rope. 

The key to keeping the different loops in place is using enough sewing pins.

Ad hock set up to wrap the ball. 

The first two directions wrapped and the spacers removed. Ready for the third series. 

Not shown, the long painful process of untangling the rope when I realized that I had put too many loops. The original plan was 15 wraps in each direction. It worked better after trial and error with 13 wraps. 

About an hour later the knot is finally tightened to this clean appearance. 

Using the "fishtail" braiding technique, I created a thick handle for the kettle bell. the two remaining strands of the original knot were tied near the base of the other to create the parallel base strands. Then another length of rope was tied in a cross over pattern.