Ava came trotting back from the yard looking like she had lost a bet with a swamp, and her owner had finally had enough. The daily ritual of wrestling a mud-caked dog clean was grinding him down, and with a large wooded property that seemed to generate mud on command, the problem was not going away. So he did what engineers do when chores become intolerable: he built a machine.
An arch, 15 spray heads, and a shocking parts count
The concept started with a clean geometric problem. If you want to wash every surface of a dog with a standard garden hose, you cannot simply aim a nozzle at it from one direction. The solution he landed on was a scanning arch fitted with 15 spray heads that pivot up and down, sweeping the full length and width of the dog as the arch travels on a linear track. A separate undercarriage nozzle handles the belly and leg pits. A second set of nozzles on each sprayer would, in theory, switch from water to air and blow the dog dry once washing was done.
What looked elegant on a computer screen turned into a parts explosion in the real world. Each of the 16 spray heads was itself an assembly of multiple 3D-printed components with internal water and air channels, O-ring seals to allow pivoting, and replaceable nozzle tips. When the first prototype was printed, ‘a bunch of stuff didn’t fit’ and the flow path had to be redesigned from scratch. The arches, bent from galvanized tubing and welded by hand while wearing a powered respirator against the fumes, took significantly longer than planned. The wooden base got so many coats of polyurethane that, as he put it, he was ‘not sure if they’re wood or plastic anymore.’ All the motors run inside custom waterproof enclosures. A microcontroller cycles the relays that sequence the wash, and a neck loop of the kind used in professional dog grooming keeps the animal calm and centered.
A newly arrived Tormach 15L CNC lathe did end up making its way into the build despite a stated intention to stick to accessible tools. The gantry wheels came off that machine, and he spent time setting up an automated bar-pull cycle that let the lathe cut wheel after wheel without supervision, which he described as something close to a low-quality roller coaster in motion.
A borrowed dog named after a piece of cheese saves the day
The first live test with Ava went badly. Flow out of the upper nozzles was weak, and her head sat too far forward for the arch to cover her back. The gap between the floor boards was a tripping hazard. Ava herself was shaking. ‘She’s terrified,’ his wife said, and that was the end of that session.
For the second test, the family recruited a borrowed dog with a very different disposition: one named after a piece of cheese, whose defining characteristic was that she did not care about anything. The kids applied a thorough mud treatment before the run. With redesigned nozzles and the math actually done this time, the machine cleaned her convincingly. One remaining quirk: the left and right side sprayers move independently, so at the top of the arch they point toward each other, colliding streams that cancel out and leaving a narrow strip of less-clean fur along the dog’s spine. ‘A mohawk of lower cleanliness,’ he called it. The drying cycle, for now, is tabled.
His wife scored the machine a solid eight out of ten, docking two points because the dryer was promised and did not deliver. For Ava’s sake, she gave it a zero. ‘She cannot be washed at all with it,’ she said, with the Geneva Convention mentioned as a reason not to simply strap the dog in anyway.
Bri, mid-cycle
The borrowed dog, Bri, standing inside the arch with water sheeting off her from every angle, a mohawk of soap and mud still standing along the ridge of her back.
Ava is still getting muddy every time the yard calls to her. The machine works, one cooperative dog has proven it, and the creator’s wife has made her position on its household utility very clear.
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