Okay, so I decided to mess around with a pressure blaster gun. Had this old, grimy engine block I wanted to clean, and thought, why not build something to do the job? Commercial ones are pricey, and I like getting my hands dirty anyway.

Getting Started - The "Bright" Idea

It all started one Saturday morning. Staring at that caked-on grease, I figured a bit of focused, high-pressure air mixed with some abrasive could do wonders. Looked up a few basic designs online, nothing too fancy. The main bits seemed to be a hopper for the grit, a gun body, a nozzle, and a way to connect it to my air compressor. Seemed simple enough, right? Famous last words.

Scrounging for Parts

First thing, I raided my garage. Found some old plumbing pipes, a few fittings, a beat-up funnel that looked like it could be a hopper. This is where the "fun" began. Nothing quite fit together perfectly, of course. So, off to the hardware store I went. Spent a good hour just wandering the aisles, picking up bits and pieces. Some brass fittings here, a ball valve there, a length of sturdy hose. The cashier gave me a funny look, probably thought I was building some kind of Frankenstein contraption. Wasn't far off, to be honest.

The First Assembly - Or, How Not to Do It

Got back home, all excited. Started wrenching things together. My first attempt at the gun body was, well, a disaster. I basically just tried to connect everything in a straight line. The hopper was just sort of balanced on top. Leaks everywhere. Air hissing out from every joint. And when I tried to feed some sand through it (just regular play sand to start), it just clogged up instantly. Pathetic.

Felt like throwing the whole thing across the yard. But, took a breath, grabbed a coffee, and sat down to rethink.

Round Two - A Bit More Thought This Time

Okay, so brute force wasn't working. I realized the air flow and the media feed needed to be managed better. I focused on sealing the connections properly. Used a ton of thread seal tape. Like, an entire roll. Then I worked on the pickup tube for the abrasive. Had to get the angle right, and the size of the opening. Too small, it clogs. Too big, it just dumps everything out at once.

The nozzle was another tricky bit. My first "nozzle" was just the open end of a pipe. Shockingly, that didn't create much of a blast. I ended up finding a ceramic tip from an old welding torch that I managed to adapt. That seemed more promising.

• Sealed all connections. Again. And again.
• Redesigned the media inlet to the gun.
• Fashioned a new hopper that actually sealed a bit better.
• Fitted that ceramic nozzle.

Testing, Testing... Success? Sort Of.

Time for another test. Hooked up the compressor, filled the hopper with some fine grit this time. Stood back, pointed it at an old rusty metal sheet I had lying around. And pulled the trigger.

Whoosh! It actually worked! Well, kind of. It blasted, alright. But it also coughed and sputtered a bit. The media flow wasn't super consistent. Sometimes it would blast hard, other times it would just puff out air. But hey, progress! At least it wasn't leaking air from every pore anymore.

Fine-Tuning and Actually Using It

Spent the next couple of hours just tweaking it. Adjusted the air pressure. Played with the media valve (which was just another ball valve I'd added). Tried different angles for the pickup tube inside the hopper. It was a lot of trial and error. Mostly error, if I'm being honest, but I got there.

Eventually, I got it to a point where it was working pretty consistently. Took it over to that engine block. And man, it stripped off that old grease and grime like a charm. Not as fast as a professional setup, I'm sure, but for a home-built rig, I was pretty chuffed. It made a heck of a mess, though. Grit everywhere. Definitely an outdoor activity.

So yeah, that was my adventure in building a pressure blaster gun. It wasn't pretty, and it took some cursing and head-scratching, but I got a working tool out of it. And I learned a fair bit about how these things actually operate. Plus, saved myself a few bucks. Mostly. If you don't count the hours spent fiddling, anyway.