Watermelon Smasher (Post-Apocalyptic Spiked Mace)





Introduction: Watermelon Smasher (Post-Apocalyptic Spiked Mace)

About: I am the most happy when I am tinkering or fixing something.

They are coming.  Make no mistake about it.  The watermelons will rise, and when they do, nothing can stop their insatiable need for human flesh.   Guns?  Too loud.  Blades?  Too easy.  In the chaos to come, you will need a weapon that can be made with simple household items and requires no maintenance.  Behold, the destructive simplicity of the WATERMELON SMASHER!!!

***Cold Steel used to make a battle mace, but it is discontinued.  I saw one recently on eBay for over $50.  This is my attempt at a homemade version.

Step 1: Safety FIRST

I am dissapointed that I have never really discussed safety in any of my previous instructables.

Protect yourself.  I use safety glasses, hearing protection (around power tools) and work gloves at a bare minimum. 

Step 2: Gather Materials and Tools

  • tin can
  • concrete mix
  • 1/2" by 1-1/2" bolts, lock washers and nuts (12 each)
  • metal pipe
  • wooden handle
  • spray paint (optional)
  • misc screws

  • power drill and bits
  • hacksaw
  • file
  • wrench
  • bucket
  • pencil


Step 3: Prepare the Tin Can

  • Layout your pattern (I chose three rows of four bolts each...AKA "The Rind Buster")
  • Drill some pilot holes  (Take care as the tin can is not very strong at this point)
  • Drill 1/2" holes
  • File off any metal shavings
  • Insert bolts and tighten nuts

Step 4: Cut Pipe Sleeve

  • Cut pipe sleeve to length (4" above the top of the can, mine is 8-1/2" overall)
  • Drill holes in the bottom of the pipe (for anchor screw)
  • Insert screw
Note:  The purpose of the anchor screw is to provide something for the concrete to mold and cure around.   I don't want the pipe sleeve to slip out of the concrete over time.

Step 5: Add Concrete to the Head Assembly

  • Mix the concrete (Mix more than you think you need.  I chose a drier mix to increase my chances of having stronger concrete after curing. It was the consistency of peanut butter.)
  • Insert the pipe sleeve into the tin can.  Center the sleeve.
  • Add concrete in layers; packing down with pencil.
  • Cure concrete (I placed a damp rag over the exposed concrete and put the entire assembly inside a plastic grocery bag. Total cure time was 3 days.)
  • Paint assembly (OLIVE DRAB GREEN.  It's good enough for a Sherman tank, it's good enough for a watermelon smasher.)

Note:  The completed head assembly weighs 5 lbs.

Step 6: Connect Head Assembly to Handle

  • Cut handle to length (This is a matter of personal preference; I chose 28" overall.)  I repurposed a broken shovel handle.
  • Insert the handle into assembly and secure with a lag screw.

Step 7: Smashing Time!


Future Improvements
  • Stronger alternative then a tin can.  Steel pipe or wood block?
  • This version is pretty heavy (the head assembly weighs 5 lbs.) I would like to make a shorter, one-handed version that weighs less than 2 lbs.

Thanks for viewing.  Fire away with any questions or comments.
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34 Discussions

Gallagher would be proud of your work :)

That is the most dangerous but awesome looking thing I've ever seen.

Could I use a broomstick for the handle? I try this as it seems like an excellent idea.

I went with cast aluminum. Also ran a 4"bolt out the end, to stab/slash with. Length about the same as yours. To keep the handle from wearing/splitting I wrapped it with metal duct tape to fill the gap. My photo didn't turn out. Will try later.

"This version is pretty heavy (the head assembly weighs 5 lbs.) I would like to make a shorter, one-handed version that weighs less than 2 lbs."


I see what you did there. You added weight to the head so the can doesn't collapse. Very nice touch. This is the best DIY design I've seen in 15 years on the internet.

This. Is. Brilliant.

My brain is already racing to figure out a spherical-mace version. Perhaps by putting two identical metal bowls together?

Or a spiked-ball-on-a-chain version...

1 reply

Heres something you may be interested in. Youth sized bat with long screws or nails going thru it ever which way but loose. Almost have mine done.

Awesome! Gotta make this! I agree, gotta design a 2 lbs. version. I remember an old version of a mace, but it uses a youth sized bat and screws or nails. Wouldn't recommend that one for the kids of course. lol

Nice idea, if you want to make it more durable use threaded rod and go through both sides of the can.

I made one and it works great :D thanks man! I will be using it for a post apocalyptic film for class

are you using a regular soup can? I am going to do this with a small coffee can (bigger than a soup can to make a slightly larger one) what size bolts should I get?

1 reply

I used a broken shovel handle that I had. You can buy new handles from Home Depot or Lowe's for less than $10.

Just wanted to say congratulations on being a finalists in the Concrete & Casting Contest! This was a fantastic instructable! Good luck!

1 reply