Untitled Gardening Project #33

'Dress' the inner and outer edges of the slot in all 24 plates using a rotary tool with a 220-ish grit bonded abrasive wheel. Go beyond deburring to the point of intentionally rounding over the exposed edges. During final assembly, we'll need to seat gasketing into the slot without the benefit of unobstructed mechanical access, so a rounded edge will be essential for getting things to seat easily.

This will generate lots of fine aluminum/abrasive dust.In fact, it will probably burn up an entire 7/8" wheel per plate. That's enough dust to worry about two things:

1. If your rotary tool (eg "Dremel"(tm)) has a mechanical speed switch, you'll almost certainly end up shorting it out because the dust is conductive. The ones with sealed/electronic speed controls don't seem to have this problem.

2. Ingesting and aspirating aluminum dust usually isn't a problem because there's a ton of aluminum in the environment and the human body can normally eliminate surprisingly large amounts without harm even if the exposure is long term. Multi-generational epidemiological studies observing workers with high chronic exposure bear this out (the real concern is silicosis from overwhelming the lungs' dust elimination capacity-- not really a concern here). However, there's alot of naked olfactory nerve endings up your nose unprotected from environmental toxins and there's recent concern you can damage this tissue from inhaling extremely fine aluminum dust. Since using one of these abrasive wheels will turn my boogers black for a week, I think I can safely assume lots of the dust would get up my nose. For this reason, I wore a heavy-duty filtermask for this step even though I virtually never bother for other 'dusty' operations.