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Rimless/ Braceless Tank - Glass Thickness

Vinkenoog1977

Vinkenoog1977

Member
Joined
14 Apr 2014
Messages
560
Location
The Hague, Netherlands
Hey guys,

Just a question to check if I've done this correctly. I'm planning a largish tank at the moment, and I'm looking for an open top, rimless and braceless tank, ordinary glass, transparant silicone. Anyways, I've checked out the calculator from fnzas, but I'm not sure if I've used it correctly.

The dimensions of the planned tank are 120 x 40 x 40 cm. The above stated calculator give me a glass thickness of 8 mm. for a safety factor of 5,2, with a bending of 0,19 mm. Couple of questions:
1. Did I use the calculator correctly, i.e., are my numbers correct?
2. Will this suffice, i.e., is a safety factor of 5,2/ a glass thickness of 8 mm. enough for this style of tank?
3. Do these results mean that, when filled, the front and back panel will bend out for a maximum of 0,19 mm.?

Thanks!
 
8mm seems very thin for a 4 footer. I think even a braced would be 10mm at 4 foot. Not 100% on that though.

I haven't tried the calculator but I'm currently looking for a 5ft braceless and this needs 15mm. Surely you should be around the 12mm mark at least.
 
Thanks for the replies guys, my gut-feeling kept telling me the same, however, when I started "checking my gut on the interwebs", it kept coming back with 8 mm. I even checked the ADA tanks, and, believe it or not, they are 8 mm. as well, at least the Optic White is (the Cube Garden 120P IS 12 mm.) and the 120P is slightly bigger (120x45x45). Or has Optic White glass a higher tolerance or something? 😳

I thought these calculators where supposed to resolve the confusion around glass thickness, not fuel it. 😡
 
I'm no tank builder but I'd want at least 10mm so I could sleep at night😀
 
Vinkenoog1977 said:
I thought these calculators where supposed to resolve the confusion around glass thickness, not fuel it. 😡
Click to expand...

lol

If ADA's doing it then who are we to argue? :shifty:

I suppose it comes down to budget really. Go cheap with 8mm and constantly have a doubt in the back of your mind, or over do it just to make sure.

Just to say as well, a 5ft braceless used to be made in 12mm, everyone I've contacted now has gone to 15mm. They must have learnt something from experience. Can you post a link to the calculator so I can check what it says? Just to see if it still goes with 12mm.
 
I'm going to go with 12 mm., my peace of mind if worth the extra 75 Euros. 😉 Just for the hell of it, I will ask my LFS about what they would build it out of, out of curiosity.

This is the page with the whole story and links to the calculator. And here is the Excel-sheet, which I found easiest to work with.
 
I can't open the sheet on this, even through google drive, so I'll have a check tomorrow on the PC and let you know. One thing I did notice though is the date on the article 😉

A new tank is a big expense, so an extra 75 is worth it IMO :thumbup:

I still can't believe ADA do 8mm tbh. I knew their tanks were way overpriced and surrounded by hype, but the term "daylight robbery" springs to mind :angelic:😀
 
Nathaniel Whiteside said:
My 90p is 10mm...
Click to expand...

I still stand by my original statement 😛 😀

Nathaniel Whiteside said:
I'd go at least 12. Apparently the old old ADA tanks used to bow like hell on the front.

Sack waiting for that to blow.
Click to expand...

I once had a juwel rio 400 go braceless all by itself :lol:

Just the sound of the braces going was pretty scary, but seeing the glass bowing as much as it did was nothing short of terrifying. I measured it but can't remember exactly. It was a good inch difference at least though. I did get new braces but juwel told me it would stand up to the bowing :nailbiting:
 
Last edited:
My 120x45x45 is 10mm no visible bowing just to throw that into the mix
 
It's the bowing that concerns me most, and I want none of that! But now Ollie has me doubting about going for 10 instead of 12; would save me enough for most of the planting, but still... I'm going to pop down to my LFS tomorrow, and stop by a couple of glass suppliers nearby, and see what they come up with. For now, I'm still thinking 12 mm. is the way to go!
 
Well, that was an interesting morning. I visited two LFS, and two glass suppliers/ makers, and I got 3 different answers, and nearly caused a fight at the LFS. The first stop was at a LFS, and they were pretty straight forward... And told me 8 mm. would be plenty... Right... Then came the two glass suppliers; the first one was quite thorough, did some calculations, and came with a minimum thickness of 10 mm., but 12 would be better. The second glass supplier had a short and simple answer; 12 mm.
At the second, and my regular, LFS, this question nearly caused a fight between the staff, well, let's call it a heated argument; 8 mm. vs. 12 mm. They went to and fro, threw some curse words in there, and well, decided to agree to disgree.

For me, it's clear now, and it's going to have to be 12 mm.!
 
I've just build a rimless tank 700x450x400mm and used 10mm glass, No way would I consider using any thing less for a diy tank, not because the glass is too thin but because the silicone joint is not strong enough

For 1200mm tank I would personally use 12mm glass, thicker glass = bigger surface area for the silicone = stronger joint.

Bowing in the front and back pane isn't a major issue as long as it not excessive (over 3mm) and happens on all tanks.
It's pressure on the seams thats the issue, and is what causes leaks and blow outs.

In larger tanks (120l+) excessive bowing creates more pressure on the seams, the thicker the glass the less bow.
Like I said above thinner glass gives less surface area for the silicone meaning a weaker seam and thinner glass will bow more.
Thicker glass gives the silicone more surface area resulting in a stronger seam and less bowing.

I believe companies like ADA, fluval, juwel etc can use thinner glass because of the building process and silicone used.
The tanks are machine made for precision and accuracy and the silicone used it far stronger than whats available to the public.
Because of this the seams on their tanks are much stronger and so thinner glass can be used, not to mention its also more profit for them!

It would be near impossible to achieve the same precision and strength from a DIY build.

Especially if you're building the tank by laying down beads of silicone and placing the glass on top, this usually results in uneven seams that are weaker than a precision machined joint.

For this reason thicker glass is recommended for diy tanks for the increased seam strength.

Its also worth getting all edges of your glass polished.
When thicker glass is cut the break can be uneven resulting in lumps and bumps along the length and out of square edges.
Having the edges polish should ensure they are nice and true.

Also remember silicone needs 1 day per 1 mm to cure, so if you're using 12mm glass it needs 12 days+ to cure before water testing.

Have a look into silicone injecting for building aquariums, its a slightly different process than the traditional laying beads method but you can get joint accuracy much better and its easier to do though does take a lot more time.
 
Thanks for that extensive answer Dan, but, and maybe I should have been clearer, I do not intend to build the tank myself, I was just questioning what thickness I should have the tank made out of. I have room, patience, nor nerves to try out something like that as a DIY project; building stands and lighting racks, I can do that, and trust my skills enough to know it will stand the stresses and the test of time, but not with something like this; I'd like to have someone else do it, and give me a guarantee on it as well, I'm sure my insurance company, and the neighbours downstairs, will appreciate it. 😉

I will ask them if they use, or can use, silicone injection, and have the edges polished, and beveled. The difference between regular and injection, from an estetic point of view, is incredible, and I'm sure these guys will have access to the strongest of silicones! Going to get some quotes now, and take it from there!

Thanks for all the input!

P.
 
Ah sorry my mistake, I thought you where intending on building it yourself I've got making things on the brain at the moment 🙂

10mm should be adequate, 12mm will give you complete peace of mind if you dont mind the aesthetics of the thicker glass.
 
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