Hey guys - new tank (60x30x40cm) and I'm planning on using a small coffee table (45x30cm). It sits nicely par about 5cm over hang of the aquarium.. Is this something I should be wary of and get a larger table/stand?
The stand should be just big enough, or bigger than the footprint of the aquarium. If the aquarium is larger than the stand, it is not suitable. I have seen some people use relatively thick plexi as a "base" to the aquarium that had overhang and resulted in an interesting aesthetic, but the entire base of a normal aquarium is designed with the assumption it will be properly supported.
You could use a double layer, glued together, of 3/4" plywood, the same size as the tank, screwed and glued to the top of the table. I would worry about a single layer gradually bending down at the ends leaving only the middle supported.
No, the tank needs to be supported 100% everywhere. That is why you see styrofoam used under big tanks to compensate for any surface irregularities. Glass doesn't show stress marks and after time of not being fully supported it will just break one day.
I was merely trying to stress the importance of the 4 corners being supported, though you could support a tank up to let's say a 40b by just its 4 corners. I'd almost be willing to say a 55g or 75g even. Though the weight is significant in comparison to this following example of strength, you can note if you were to put the bottom glass of a 55 or 75 resting each end on cylinder blocks and stood in the middle it won't break.
Being a mechanical engineer, this was an issue that I had some interest in. My tank is sitting on an old cabinet, and only the corners make contact due to the center bowing downwards slightly. After a lot of calculations, I determined that this would be fine, and got a factor of safety of 2.7 with only the corners supported on a 55 gallon. After searching for a while, I found this which confirms to me that only the corners need support:
The real key is that all corners are level... what I think breaks most tanks is one or more corners being slightly higher or lower than the others which places the glass under torsion. Over time, the added stress of twisting the glass causes a failure. Glass, being very brittle, is not suitable in situations where any bending or twisting is present.
All of the calculation I have done use the material properties of tempered glass, and for a tank with a plastic rim. I'm not sure how a tank with annealed glass would behave with only supported corners.
Serious question or this going to be one if those smart ass pick a argument moments.
Yes, it was a legit question
My reason for asking was purchasing a new tank and noticing the stand supports all 4 corners, but has a CD thick gap on the front edge meaning 3 sides and 4 corners fully supported. Being an ME myself, thoughts of this potentially causing stress have been preventing me from filling the tank. It's been sitting empty in my living room for a while now until i find an acceptable, and eye-appealing stand
The hockey puck example was an extreme example, but i wonder how many 55G tank setups on paticle board stands have a sagging center section?