The Fish Tank

Ok people,
I've had three comments on this blog so far, and two of them have expressed concern about the fish tank. I thought I'd put a few more details here about it to put minds at rest.

The tank will not be made out of glass. Glass is a much trickier substance to work with. Instead it will be made out of perspex. Perspex has many advantages in terms of fish tank building; it's stronger, clearer, can be easily drilled, is more thermally insulating, and is much lighter than glass. It also has almost exactly the same refractive index as water, so light does not bend when passing from perspex to water. The main disadvantage of perspex is it does tend to bow a bit more if you're not careful, and it scratches easier (although scratches can be buffed out of perspex, unlike glass).

Perspex is also easier to bond together than glass. By applying a solvent to the perspex, it actually melts slightly. Then when the solvent evaporates away you have a bond that is just as strong as a sheet of it, and is even clear! These bonds also never age and give way, unlike glass tanks, for which the joins are well known to weaken with age.

Another advantage I have for the perspex is that it can be cut using Greg's (Sally's Dad) larger router from his business. All I need to do is develop the template, stick the sheet on the bed, and the router will cut the whole thing out for me precisely and with perfectly straight edges. So the overall plan is to design the tank, decide on all the pieces I want cut, develop a template for the router, have all the pieces cut out of a single large sheet, and glue them all together.

Perspex tanks are recommended to have a roof on them, because it reinforces the top of the tank and prevents bowing. What I'm doing differently is that the tank will have a "chimney" up the back to allow access, and so that the water can come all the way up to the level of the perspex ceiling, allowing an unobstructed view through the top of the tank.

Don't worry Travis, I have considered the whole air issue. The tank is also going to have an integrated filtering system build into the back wall of the tank. There will also be a bubble rock in the filter, making sure plenty of oxygen will be absorbed into the water. There might also be another bubble rock in the main tank area, so don't sweat about dissolved air in the water.

Once I've finished the TV cabinet I'll be moving onto pondering the fish tank problem, I have plans here but they're pretty messy, I'll draw some better ones up and stick them up later. I'd just prefer the blog to focus on one project at a time.

Bye!