Anodizing

Earlier this week, I called up a local shop and they were nice enough to run one of the boilers through their hard anodizing tanks as a sample. Man does it look good! The treatment on this one is primarily on the exterior surface, for reasons I’ll explain, but I’m working up a small design change to get more of the coating on the inside of the boiler as well.

Now, even before I sent it in, I knew pretty well what the process consisted of. They dip each piece in a couple vats of nasty chemicals, apply some volts (okay, a bunch of volts) and *poof* tough exterior layer of aluminum oxide. What I didn’t think about was fluid behavior. Namely, if you’re expecting to fill and drain a container with only one hole, without moving the container, you’re going to be disappointed. If the hole is down, air pressure is going to prevent it from filling. If the hole is up, it simply won’t drain between dunks. Dumping each one out between chemicals (fixing the draining problem) isn’t in the cards, and even though I didn’t ask, I suspect that running the whole process in a vacuum (fixing the air pressure problem) isn’t either.

What they suggested is that I create another small hole opposite the spout on the top of the boiler so that it could be placed on the rack horizontally to fill and drain completely. At first I wasn’t too excited about the idea of creating another hole that I would just have to plug up. But then I got an idea about how I could put that hole to use. Stay tuned…

Tagged as: anodizing, local manufacturing, Pittsburgh