Alright, buckle up, because I'm about to walk you through my weekend project: building a water-cooled machine gun. Now, before anyone gets their knickers in a twist, this is purely for fun, learning, and definitely NOT for anything nefarious. It's all about the engineering challenge!

So, it all started with me staring at a spare airsoft gun I had lying around. I thought, "This thing gets hot when I'm laying down suppressing fire... What if I water-cooled it?" A ridiculous idea, I know, but I couldn't shake it.

First things first, I grabbed the gun and started disassembling it. Needed to figure out where the hot spots were and how I could even attach anything resembling a water jacket. Turns out, the barrel area was the prime candidate. I took measurements, lots of them. My initial thought was to 3D print a custom water jacket that would snugly fit around the barrel.

Next, the CAD software came out. I spent a good chunk of Saturday morning designing a two-part jacket with channels for the water to flow. It was a bit tricky getting the tolerances right so it would actually fit, but after a couple of revisions, I had something I was happy with. Then, I fired up the 3D printer. ABS was my material of choice – it's relatively heat resistant and easy to work with.

While the printer was doing its thing, I scrounged around for the rest of the components. I needed a pump, some tubing, and a reservoir. An old PC liquid cooler pump I had lying around became the heart of the system. For the reservoir, I just repurposed a plastic bottle. Hey, gotta start somewhere, right? Some clear vinyl tubing from the hardware store completed the loop.

Sunday morning, the printed jacket was ready. I carefully removed the supports and did a test fit on the airsoft gun. Success! It slid on pretty nicely. Now, for the plumbing. I drilled some small holes in the jacket for the tubing connectors and used some epoxy to seal everything up tight. I really didn't want any leaks.

With the jacket installed and the tubing connected, I set up the pump and reservoir. I filled the reservoir with distilled water (to prevent corrosion) and plugged in the pump. Time for the moment of truth! I watched closely for any leaks. Thankfully, everything seemed to be holding up. The water was circulating nicely through the jacket.

Now, the real test: firing the gun. I loaded up a magazine and let rip. I could definitely feel the difference. The barrel stayed noticeably cooler than it usually would. I even set up a temperature sensor to monitor the barrel temperature over time. The water cooling was definitely doing its job!

Problems I encountered: the 3D printed jacket, while functional, wasn't the prettiest thing in the world. Also, the plastic bottle reservoir was a bit janky. I'm thinking about upgrading to a custom-made reservoir and maybe even machining a metal water jacket for better heat transfer.

What I learned: water cooling isn't just for PCs! It can be applied to all sorts of things. Also, 3D printing is an amazing tool for prototyping and building custom parts. And lastly, don't be afraid to try crazy ideas. You never know what you might learn!

• CAD Design
• 3D Printing
• Basic Plumbing
• Electronics (pump)

Final thoughts

This was a fun and educational project. It's definitely not the most practical thing in the world, but it was a great way to learn about heat transfer, fluid dynamics, and the joys of over-engineering. Who knows, maybe I'll water-cool my toaster next!