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DIY Optiwhite tank build

No Nonsense Smoothing Tools Concave Joints

Use these to get perfect silicone joints.

Aye, I’m using similar tools. I have these ones
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I’ve been considering the safety of unbraced tanks and can’t help thinking it’s a combination of not only the height but also the length of the longest side on a rectangular tank? Is there a good online source that works it out for you?
 
I’ve been considering the safety of unbraced tanks and can’t help thinking it’s a combination of not only the height but also the length of the longest side on a rectangular tank? Is there a good online source that works it out for you?

There was a very good one years ago but I can’t find it any longer.

Just search for aquarium glass thickness calculator and something will come up.

It’s the height that makes the most difference as it dictates the pressure. Obviously adding in more length will have an affect but height of the tank is more of a dramatic change.
 
Is there a good online source that works it out for you?

I would rely on the information from other manufacturers, find a selection of retail tanks of a similar size to that you are planning and use their glass thickness as the benchmark to base your build on.
 
I’ve been considering the safety of unbraced tanks and can’t help thinking it’s a combination of not only the height but also the length of the longest side on a rectangular tank? Is there a good online source that works it out for you?
I shared this not so long ago to calculate force on front/back glass. Once you're over 45cm height, things get a bit hairy.

For the 320x80x50 (LxWxH) i'm leaning towards a stainless steel frame.
 
I’ve been considering the safety of unbraced tanks and can’t help thinking it’s a combination of not only the height but also the length of the longest side on a rectangular tank? Is there a good online source that works it out for you?
This one seems pretty good for working out glass thickness (also works out weight of glass + water etc):
Aquarium Glass Thickness Calculator

Length of longest side is important but not as important as the height.

You need to know the safety factor you are aiming for to use this tool. For a normal braced tank 2.9-3.8 is usually the accepted value but for rimless and braceless it is less clear cut, I have seen 7.6 suggested. I believe if the edges of the glass are properly polished before manufacture these values can be reduced. Other manufacturing processes may also allow the safety factor to be reduced. If you put the dimensions of rimless tanks offered by Aquariums4Life through that calculator you have to use a safety factor around 7.2 - 7.6 to get the thicknesses they use. For some ADA tanks you need to use a factor of 5. What I would use for a home built tank? I guess depends on a combination of how much care you would take building the aquarium and how risk averse you are.

For the OP's tank the calculator gives a value of 4.75 as the safety factor at the new height.

There was a very good one years ago but I can’t find it any longer.

Yes, there was a really good aquarium glass calculator site with tons of useful knowledge in addition to the calculator itself but it disappeared about 1-2 years ago. Very annoying when useful sites disappear.
 
Thanks for that. I was thinking of maybe a 720 x 450 with a height of 400. 10mm glass gives a factor of 10 so that’s good?
 
Thanks for that. I was thinking of maybe a 720 x 450 with a height of 400. 10mm glass gives a factor of 10 so that’s good?
Yes, better to overbuild than under. You could very safely go to 450mm height in 10mm at that length. I have an ADA tank sitting upstairs empty that I bought second hand and never used. It is 750 x 450 x 450 in 8mm glass.
 
Just a comment and I am by no means experienced in DIY tanks and thinking about when sealing sanitary ware and showers. I was under the impression all joints be made at the same time when the silicon has not cured to ensure water tightness. I always thought that it is not possible to get a proper bond between cured/skinned and fresh silicon?
 
I think someone asked that originally in this thread, I never had a problem. Silicone sticks to silicone. And this stuff really sticks.

This is the 5th tank I’ve made this way and all have held up. One was used for several years without leaks. I have no concerns with this particular silicone myself.
 
I have a little bit of experience of DIY tanks, and can tell you silicon does adhere to cured silicon no problems despite what ive heard some say on the subject.

I tend to do the same and run a bead along the glass edge and press into place. It gives that added insurance of a good seal before running the second bead along the inside of the glass. I dont let the first bead cure first though so run some masking tape inside and the apply the second bead in. You could most probably get away with not adding a second inner seal and it would not leak if it was applied evenly, but why take the chance.

This is the stuff i use. Good stuff.

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Healthy bit of “it’s gone wrong so I’ll have to redo it update”.

When the glass was originally cut the sides were cut so it was a 50cm square and so was the base. The edges of the base were arrissed but the edges of the side panes were ground and polished to give a bevel. Therefore the tank is actually about 2 or 3mm smaller than 50cm whereas the base is still 50cm.

When putting in the panes of glass I have been centralising them to the base and having them flush against the edge. I made the mistake of doing this to the third pane of glass.

What’s happened is that the third pane doesn’t fit flush at the vertical edges, it’s just off. Which isn’t good enough in terms of safety and even more importantly it doesn’t look good!

So had to strip this pane out and redo it. Means loads of silicone removal again. Reassuringly, it took at least 10 passes with a razor blade and pulling back on the glass to split the seam. So it’s a very strong bond.

Have attached a photo of the edges. Hopefully this may be of use to someone should they consider building their own tank. I totally forgot to take this in to consideration.
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What are you using to strip the silicon back with? i use one of these,
s-l500.jpg


I use a dab of nail polish remover to take off any residue that left.
 
I have some of that but it didn't seem to want to do anything for me, maybe mine was from a dud batch? you just slop it on, leave and try to remove?
You must trim any silicone as thin as possible, using a sharp knife first. I then wipe with IPA/meths for ensure 100% dry. Then apply remover and go for a couple of cups of tea.

When you come back just use a non metal scraper, nylon pot scrubber etc to remove the now loose silicone "film".

Wash with water. Water deactivates the remover.

Dry, clean with IPA/meths, apply masking tape, apply silicone, smooth away with your favourite tool and/or finger soaked in Fairy liquid solution. Job done.

Soudal (at some B&Q's) also sell a silicone remover which I have used a couple of times. Similar results to Screw fix stuff.
 
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