Alright, so I figured it was high time I got myself a proper car water sprayer. The old watering can just wasn't cutting it for washing the car, and honestly, I wanted something with a bit more oomph, you know? Plus, it sounded like a decent little project to get my hands dirty with.

Getting Started - The Plan (Sort Of)

First thing, I had a look around at what bits and pieces I'd need. I wasn't looking to build a commercial-grade pressure washer, just something handy. My main thought was, I need a pump, some tubing, a nozzle, and a way to power it. Seemed simple enough on paper. Famous last words, right?

I ordered a small 12V diaphragm pump online. Looked decent, promised enough pressure for what I needed. Then I got some flexible PVC tubing, a few different spray nozzles to play with, and a cheap plastic jerry can to act as the water reservoir. For power, I figured I'd just use the car's 12V accessory socket for now.

Putting It All Together - The Fun Part

When the parts arrived, I laid them all out on the garage floor. The initial hookup was pretty straightforward. Pump inlet to a tube going into the jerry can, pump outlet to another tube with a nozzle on the end. I used some hose clamps to make sure things were tight. Or so I thought.

• Connected the pump to a spare 12V battery I had, just for testing.
• Dropped the intake tube into a bucket of water.
• Flicked the switch.

And... nothing. Well, not nothing. The pump whirred, but no water came out the nozzle. Just a sad gurgle. My first thought was, "Great, a dud pump." But then I remembered these things sometimes need priming.

Oops, and Fixes

So, I fiddled around, tried to get water into the pump manually. That was a bit messy. After a few tries, and getting a bit wet, it finally caught. Water started spraying! But, oh boy, the pressure was a bit underwhelming. And one of the connections on the outlet side was leaking. Not a lot, but enough to be annoying.

Back to the drawing board, sort of. I tightened the hose clamp on the leaky connection as much as I dared. That seemed to fix the leak. For the pressure issue, I swapped out the nozzle. The first one I tried was a wide fan type, probably too much for this little pump. I switched to a more focused jet nozzle, and bingo! Much better pressure. Good enough to blast off dirt, anyway.

Then I decided to wire it up properly with a switch and a cigarette lighter plug. That part was easy enough, just some basic wire stripping and connecting. Made sure to put a fuse in line, just in case. Don't want to be blowing fuses in the car.

The Final Product and Testing It Out

With everything hooked up and seemingly working, I filled the jerry can, chucked it in the boot of the car, and plugged the sprayer into the 12V socket. It worked! I could actually wash the car without running a hosepipe all the way from the tap.

It's not perfect, mind you. The pump is a bit noisy, and you have to be mindful of how much water you're using because the can isn't huge. But for quick rinses, or getting mud off the lower parts of the car, it's pretty darn good. I even used it to water some plants that are a bit far from the house tap.

Overall, a successful little venture. Took a bit of tinkering, a few "why isn't this working?!" moments, but that's half the fun, isn't it? It's not the prettiest setup, all wires and tubes, but it does the job I wanted it to do. And I made it myself, which is always satisfying.