Weir Teeth Material

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Midwater

Midwater

Redtail Catfish
MFK Member
Dec 30, 2021
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Thailand
It seems that in general, weir teeth are made from acrylic.

I find that after a few years, the teeth begin to get brittle, and I have a few times had to fix or change the weir teeth on various aquariums.

So I am considering what to use on the next project, which hopefully should be maintenance free ad infinitum.

There are three vague ideas:

1.) Use acrylic, but much thicker. Not three mil, but six, or eight.

2.) The entire sump front plate will be made of glass, and I cut teeth directly in the glass (or get the factory to do it), and then get it tempered.

3.) Use stainless steel mesh (similar to what can be found here) instead of teeth. And possibly use a mesh with a solid surround that can fit vertically into a slot at the top of the overflow box, so that I can remove it, clean it and/or replace it.

What do you think? Slam my ideas if you think they are rubbish. Any other ideas?
 
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If the teeth are the problem then implement a design without teeth? Some examples might be:
* use long slots or holes with an intact top edge. (Set top edge to be emergency overflow height),
* use a mesh screen as you suggest
* use dual sheets - front sheet/plate slightly off bottom (so water draws off bottom) and back plate sets water level height. Use black front plate or you will constantly see mulm & algae, allow enough distance between plates for a cleaning brush.

If you must use teethed weir;
* Polycarbonate is 250 stronger than acrylic and less likely to chip.
* use an aluminium plate.

I don't think you can get glass cut for weir teeth. Even if you could cut float then temper, the tempered glass will not provide the chip resistance you seek. (It's frail on edges).
 
fishdance said:
If the teeth are the problem then implement a design without teeth? Some examples might be:
* use long slots or holes with an intact top edge. (Set top edge to be emergency overflow height),
* use a mesh screen as you suggest
* use dual sheets - front sheet/plate slightly off bottom (so water draws off bottom) and back plate sets water level height. Use black front plate or you will constantly see mulm & algae, allow enough distance between plates for a cleaning brush.

If you must use teethed weir;
* Polycarbonate is 250 stronger than acrylic and less likely to chip.
* use an aluminium plate.

I don't think you can get glass cut for weir teeth. Even if you could cut float then temper, the tempered glass will not provide the chip resistance you seek. (It's frail on edges).
Click to expand...

Yes, I have been thinking that a toothed tempered piece of glass is not practical.

And I was already decided on dual backplates with a three mm gap under the front plate. This will draw water both top and bottom and is on two of my tanks already.

Polycarbonate, I had not considered, but that is a great idea.

Aluminium, I do not like. The long term effects of aluminium ions may be dangerous. Stainless steel is safer, and I can get fine pieces machined and welded.

F fishdance I appreciate your input.
 
If you don't need to surface skim then you could use submerged holes - set water height with external standpipe(s). You can fine tune the tanks exact water height with a sliding sleeve on standpipe(s). This is a much neater solution visually.

I prefer aluminium over stainless but everyone is different.
 
fishdance said:
If you don't need to surface skim then you could use submerged holes - set water height with external standpipe(s). You can fine tune the tanks exact water height with a sliding sleeve on standpipe(s). This is a much neater solution visually.

I prefer aluminium over stainless but everyone is different.
Click to expand...

I like surface skim. Not that there is much scum on the surface in freshwater, but keeping the surface moving is important for oxygenation.

The tank will be long and symmetrical with two overflow/underflow boxes, one at each end. One end will have the herbie down to the sump and the other end will house the return. What I am aiming for is a even flow both top and bottom water, from one end to the other.

It does not necessarily have to be toothed. It could be perforated plate.

It does have to last.

There are lots of new exotic materials that appear to have great properties, like carbon fibre board and polyoxymethylene. I do not know how they will do for many years in flowing water and with low to moderate levels of UV.

My current thinking is I will use a piece of perforated ss, as in:
1644234710986.png

But I am still open to all good ideas.
 
Midwater said:
Yes, more like the first picture. What material was it made from?
Click to expand...
That is called either egg crate, or light diffuser depending on the hardware store it comes from.
I have found it useful for many aquarium projects.
 
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Not all acrylics are made equal either. Use good brands such as Reynolds, Polycast or Plexiglass if you have access to. Also i like wier teethe that is cut down from the top edge by 1/2 -1 as that helps maintain rigidity of the overflow structure too.

You'll needa good shop to do it if you dont have the tools, but worth it in the long run.
 
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