How to build a small custom tank

gypsana

gypsana

Active Member
Originally Posted by locoyo386
http:///forum/post/3010436
The brace at the top is to eliminate bowing of the tank. The bowing puts the glass in bending which can really be bad for glass. Also the water pressure is the highest at the base and zero at the top of the tank. Most aquarium silicone can handle (with ease) tanks that are 20 gallons and have a max height of 18". The only thing that might cause the tank (that small) to leack, is not applying the silicone correctly (ie., living air bubbles, not allowing to cure properly).
Also the smallest tank that I have seen braced is a 55. This is becuse it is 48" long and 21" tall.
I worked at a glass shop for years and I had someone bring in a tank
in which the top brace had broken off and the tank bowed and leaked. Just wanted to put that info out there because it has happened. Better to be safe than sorry IMO.
 
gypsana

gypsana

Active Member
Originally Posted by taznut
http:///forum/post/3010458
this is what i was told by a place in town that cuts glass... it was 3/8" and not tempered....
and i think he should use 1/4", i was saying i used 3/8 for my 135gal (and i did so on my 55g sump even though it was probably overkill...
That glass shop is a rip off
 
taznut

taznut

Active Member
Originally Posted by gypsana
http:///forum/post/3010478
I built my own tank as well and acrylic scratches easily.

i have never had an acrylic tank before and i keep hearing this.. i left the paper on the front of mine to try and prevent this until it is set up.. there are some scratches on the bottom (not concerned about this) but they are not that deep and i dont think you would see them with the water... this may have been a bad idea but i hope not...
 
locoyo386

locoyo386

Member
Originally Posted by taznut
http:///forum/post/3010461
i picked up a few pieces of acrylic to practice with but it really is easy if the pieces are cut correctly...
as for bracing... i agree you should go with 1/4" on either glass or acrylic... with the glass, there isnt a center brace on smaller tanks but they do have that plastic ring around the top (even on 10g)... with the acrylic you could put little strips (1-2") around the entire top... im not sure that it is completly needed but, IMO, it couldnt hurt anything...
The plastic rim around the top is basically to cover the glass edge. it does nothing structurally speaking.
 
locoyo386

locoyo386

Member
Originally Posted by gypsana
http:///forum/post/3010471
I worked at a glass shop for years and I had someone bring in a tank
in which the top brace had broken off and the tank bowed and leaked. Just wanted to put that info out there because it has happened. Better to be safe than sorry IMO.
What size tank was it? How tall was the tank?.
Also not that it means anything, but I work at a Structural Engineer firm and I know where the maximum stresses are in the tank. I also know where they occur on the glass and how they affect the tank.
 
uneverno

uneverno

Active Member
20 gal tank of those dimensions should not require any bracing. I have an All Glass 20L (30x12x12). It has 1/4" untempered glass, including on the bottom, and no top bracing at all.
I used to have a direct contact w/ All Glass when I lived in MKE. They don't start using tempered until the 55 gal range. (Bow fronts may be an exception - I lost my contact before those came into existence, so IDK.)
Personally, I'd use acrylic just for the building/aesthetic considerations. Plastic weld seals almost immediately and completely within the joint, where you'll have to go to great lengths to ensure that the silicone seals are seated and don't move for at least 24hrs on glass. Not to mention unless you're a master at caulking, you're stuck with the look of a sloppy seal if you mess up.
I'm not that good a builder though.
 
locoyo386

locoyo386

Member
Originally Posted by uneverno
http:///forum/post/3010554
20 gal tank of those dimensions should not require any bracing. I have an All Glass 20L (30x12x12). It has 1/4" untempered glass, including on the bottom, and no top bracing at all.
I used to have a direct contact w/ All Glass when I lived in MKE. They don't start using tempered until the 55 gal range. (Bow fronts may be an exception - I lost my contact before those came into existence, so IDK.)
Personally, I'd use acrylic just for the building/aesthetic considerations. Plastic weld seals almost immediately and completely within the joint, where you'll have to go to great lengths to ensure that the silicone seals are seated and don't move for at least 24hrs on glass. Not to mention unless you're a master at caulking, you're stuck with the look of a sloppy seal if you mess up.
I'm not that good a builder though.
The reason your tanks does not have a tempered bottom is because it is only 12" tall. Also, you do not have to use tempered glass for the bottom. Do note that the bottom piece will always act in bending thus going to feel more stress. The volume will play a great deal of factor on tanks greater than 30 gallons. You are correct that tanks smaller than 55 do not have tempered bottom pieces, but they are thicker than 1/4" though. Like I mentioned before if he goes with non tempered bottom piece than I would recomend 3/8" thick or thicker.
 
gypsana

gypsana

Active Member
Originally Posted by locoyo386
http:///forum/post/3010534
What size tank was it? How tall was the tank?.
Also not that it means anything, but I work at a Structural Engineer firm and I know where the maximum stresses are in the tank. I also know where they occur on the glass and how they affect the tank.
From the size I am guessing about a 20 gallon and the silicone may have not been applied correctly.
 
locoyo386

locoyo386

Member
Originally Posted by gypsana
http:///forum/post/3010570
From the size I am guessing about a 20 gallon and the silicone may have not been applied correctly.
In all honesty, I do not see a 20 gallon bowing enough to cause a break on the bond of the silicone. I would imagine that if it was a do it yourself tank, than one of two things happened; the silicone was not applied correctly, or they used the wrong type of silicone. My opinion is that the bowing (diflection of the glass) will not be a problem untill you get into a volume of around 50 gallons or more.
 
uneverno

uneverno

Active Member
Originally Posted by locoyo386
http:///forum/post/3010567
The reason your tanks does not have a tempered bottom is because it is only 12" tall. Also, you do not have to use tempered glass for the bottom. Do note that the bottom piece will always act in bending thus going to feel more stress. The volume will play a great deal of factor on tanks greater than 30 gallons. You are correct that tanks smaller than 55 do not have tempered bottom pieces, but they are thicker than 1/4" though. Like I mentioned before if he goes with non tempered bottom piece than I would recomend 3/8" thick or thicker.
Yup yup, absolutely correct. It's a cost/benefit thing on the manufacturing end. Not necessary/too expensive to use tempered on smaller tanks. Once into the larger tank sizes, the weight savings (i.e. consumer/wholesaler (shipping costs) benefit) vs. the materials cost starts even-ing (sp?) out. As I recall, 30 gal and above the bottom goes to 3/8" and/or includes a cross brace on the bottom framing.
I didn't mention it because for the purposes of this discussion I didn't think it necessary.
 
locoyo386

locoyo386

Member
Well I think we have gone beyond the original question. To finilize my comments, the design of the thickness of the tank is based on how much of a safety factor you want. The bare minimum even for a standard 55 gallon tank are as follows; The sides 0.212" thick, the bottom piece 0.317" thick both non-tempered glass. Also the brace at the bottom is recomemded to be placed when the length of the tank exceeds 24". The brace shall be placed iin the middle of the length of the tank. If anyone wants to discuss this subject anyfurther send me a messege.
 
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