Monday, September 08, 2014

Fiddling with acylic

Last week I posted about the fish tank that I patched up. Didn't read it all? I don't blame you. I blathered on for pages. The plan was to make it a small aquaponic system. I could cheap out and put a plastic tub on top... in fact that's what I did do, eventually. But before I resorted to the tub I had a dream. I wanted a custom made tank that fit perfectly over the aquarium and was decorative as well as functional. After all, I'm putting this in my front window for anyone to look at. I'm making a museum piece... out of a ugly, patched fish tank... perhaps not my best idea. Today I want to tell you what I did, where I succeeded, and where I went wrong.

There's my design. It sits on top of the aquarium with 3/4" legs hanging over the ends to keep it from slipping. The long edges hang over the front and back of the tank by about an inch each way. The gap at one end was where the automatic feeder would fit and hoses would come out.

I'm not sure if you can tell, but the corners of the long ends isn't square. It's rounded. Back in college I was shown how to use this strip heater to soften plexiglass so it could be shaped into a small picture holder. That stuck with me and I've been wondering for years if I could do the same thing with a heat gun. Turns out you can.

The trick is to control where the heat goes. You want only a narrow band heated. I accomplished this by putting aluminum foil over the plexiglass with only a millimeter or two exposed between sheets. I used masking tape to hold the foil in place, but put the tape on unheated side so it wouldn't melt or catch fire or something.

only a mm or two exposed.

I clamped the plexiglass to a bench, slowly waved a heat gun back and forth over the gap, and gently lifted on the unclamped side. After a few minutes I was able to lift the loose end further and further until it was at a right angle. The outside of the curve had the same arc as the edge of a quarter.

At a right angle.
The second curve didn't go quite as well. It wasn't bad. But it didn't curve as smoothly. There were flat spots. I think I rushed things. Since the first corner went so well I got cocky and lifted with too much pressure. The plexiglass bent, but wasn't as soft as I might have liked.

If I were doing it again, I'd have a dowel rod handy to wrap the plexiglass around to make a nice curve.

The ends were cut out with a band saw. It was all sealed up with silicone aquarium sealer.

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