Alright, so I decided I was gonna build an electric-powered water gun. You know how it is, the ones you buy in the store? They're okay for a bit, but you're always pumping, and the power is just… meh. I wanted something with a bit more kick, something that felt a bit more serious, you know?

Getting Started - The Idea and The Junk Pile

First thing I did was rummage through my garage. I figured I had to have some bits and pieces lying around that could work. Found an old windshield washer pump from a car I scrapped ages ago. Seemed like a decent start. It’s 12V, so I knew I’d need a battery that could handle it.

Then, the water tank. I didn’t want anything too massive, but big enough for some decent spray time. An old 2-liter soda bottle looked promising. Strong enough, clear so I could see the water level, and a screw-on cap which is always handy for sealing things up.

The Guts - Pump, Battery, and Wires

Okay, so I had the pump and a bottle. Next, power. I had a spare 12V sealed lead-acid battery, the kind you use for small emergency lights or kids' ride-on toys. A bit heavy, but it would definitely deliver the juice that pump needed. I also grabbed some wire, a simple toggle switch, and a bit of tubing.

My first job was to get the pump working with the battery. Stripped the wires, twisted 'em together, quick test – pump whirred to life! Good sign. Then I started thinking about how to get water into the pump and out to a nozzle.

• Pump Inlet: I needed to get a tube from the bottle into the pump. Drilled a hole in the soda bottle cap, just big enough for the tubing. Pushed the tube through, making sure it reached near the bottom of the bottle.
• Pump Outlet: Another piece of tubing from the pump's outlet. This would be the business end.

Sealing the hole in the cap where the tube went in was key. I used a load of hot glue at first. Messy, but it seemed to do the trick. For the nozzle, I just kept the end of the outlet tube open for the first try. Figured I could always add something fancier later if it worked.

Putting It All Together - The "Build" Phase

This is where it got a bit… experimental. I needed a way to hold all this stuff. I didn’t have a fancy 3D printer or anything. So, I looked around for some kind of frame or housing. Ended up using a sturdy plastic project box I had from another failed idea. It was just about big enough to cram the battery and pump into.

Mounting the pump and battery: I used a ridiculous amount of zip ties and some more hot glue to secure the pump and battery inside the box. It wasn’t pretty, but it held. I drilled a couple of holes in the box for the inlet tube from the bottle and the outlet tube going to the "nozzle." Another hole for the switch.

Wiring the switch: Simple circuit. Battery positive to the switch, switch to the pump positive. Pump negative back to the battery negative. I made sure to solder these connections properly. Didn't want anything coming loose mid-soak.

The soda bottle, I just planned to hold separately or maybe strap to the box later if it all worked out. For now, it was about function over form.

The First Test - Leaks and Laughter

Okay, moment of truth. Filled the bottle with water, connected the tube to the pump inlet. Made sure the outlet tube was pointing away from anything valuable (or electrical!). Took a deep breath and flipped the switch.

The pump buzzed! And… water sort of dribbled out the end of the tube. Not exactly the super-soaker I imagined. And then I noticed it – water was also leaking from where the tube went into the bottle cap. The hot glue wasn't holding as well as I thought under pressure. And a bit around the pump fittings too.

Back to the drawing board (briefly): I took it apart, dried everything, and got some proper waterproof silicone sealant. Re-sealed the cap connection and tightened the hose clamps on the pump fittings. Waited for it to cure. This fixing and fiddling part is always what takes the most time, isn't it?

Second Test - Success (Mostly!)

Round two. Flipped the switch again. This time, success! A surprisingly strong jet of water shot out! It wasn't a super fine mist, more like a solid stream, and it went a good 15-20 feet. I was actually pretty chuffed. No major leaks this time, just a tiny drip from one of the pump connections I probably still didn't tighten enough.

The whole setup was a bit clunky, with the separate bottle and the heavy box. But man, it worked. It was an electric water gun, built from scraps and a bit of stubbornness.

What I Reckon Now

So, was it worth it? Yeah, I think so. It was fun to tinker and actually make something that did what I wanted. It’s definitely more powerful than any cheapo water pistol. It’s not something I'd probably carry around for a serious water fight because it's a bit unwieldy and looks like a science experiment gone slightly wrong.

Things I learned:

• Sealing things against water pressure is harder than it looks. Hot glue is not always your friend.
• That old washer pump had more guts than I expected.
• Even a rough build can be pretty satisfying when it finally works.

Next time, if there is a next time, I'd probably try to find a lighter battery and maybe integrate the tank into a more ergonomic design. But for a first go, just messing about in the shed, I’m calling it a win. It shoots water, electrically. Job done.