Can This Be Done?

[dizzied]

I was thinking about building a stand for a 20-long (30"x12") with some spare wood. Problem is, the wood just misses a foot in width - it's about 11.75". The tank would be just over 12" with the frame. Would this be dangerous?

 

[ncjharris]

Whilst building a frame and stand for a tank is very satisfying, I wouldn't reccomend it in your case for the following reasons.

While glass is (usually) strong and solid, it is very britle, which means it as a penchant for cracking. While a tank may look very stable glass is notorious for containing hidden flaws in its structure; these may be at the atomic level and unseen to eyes.
By leaving the edge of a tank unsupported, the weight of the water in the area above it won't distribute across the whole bottom, but press down on the glass below it, with the area where the glass leaves the wood being the fulcrum, or hinge.
Have this on two opposite sides and the middle of the glass is effectivley being 'bent' upwards. As glass doesn't bend, it will (eventually) weaken and crack. This may take days, months or even years, but gradually it will happen.

In your situation, if your tank is 30"x12"x12" (say), this has a volume of around 15 (UK) gallons, or 68 litres. This is then 68 kg (give or take). Taking the column of water above the unsupported end, this is about (30x30X.7) = less than a kilo of water. When I write it that way, it doesn't actually seem that bad! However, the water will cause undue stress on the glass and I still would recommend you look at seeing if you can obtain a top to your frame that the tank will sit on. This could be a piece of ply, but it needs to be think enough to transfer the weight and not bend under the weight.

As an aside, on the job I am working on at the moment, we are using toughened and laminated glass as secure windows. We thought "hunky dory", no one will be able to break them and tested it by hitting it with some wood. An independant tester came along, did some checks (including, interestingly, viewing the glass through polorised glasses), then hit it twice in one spot and the whole thing shattered. We are now using polycarbonate!

 

[dizzied]

As it turns out, I mis-measured the wood. It actually is 12". For some reason, the first inch on my ruler seems to be shortened.

 

[Ginge]

So you are saying it fits perfectly. If so do it.

 

[dizzied]

The tank actually ecplises 12", with the frame and all. Probably'll need to buy new wood. If only stands in the lfs didn't cost so darn much.