rimless, braceless shallow cube...

[dkuster]

I'm looking into building a small-ish rimless, braceless shallow cube,
and I'd like feedback on whether these dimensions and materials would
result in a structurally sound aquarium or a disaster waiting to happen :eek2:

24"L x 24"W x 16"H (water level likely to be not more than 15")

3/8" starfire glass on front and L/R sides, 3/8" "regular" (non-tempered) for back and bottom.

RTV108 silicone.

The total volume will be roughly 35 gallons.

Suggestions, comments, flames are welcome :spin3:

 

[OllieNZ]

Can't comment on the silicone but my rimless/braceless 48x18x18in is made from 10mm optiwhite (3/8 starphire in American)
Are you going to shoot for minimalist silicone work?

 

[dkuster]

Quick followup question:

Assuming 3/8" glass is "very safe", is it worth it to splurge on
starfire, or would regular float glass have similar clarity at this
thickness?

TIA!

 

[dkuster]

Hi Ollie,

First off, dumb spelling error on my part (starphire, not starfire D'Oh!)

If by minimalist silicone you mean the width of the bead along the seams, I haven't decided yet. Since it will be under the sand bed, I think I prefer the safety of a wide (maybe 1/2") bead along the bottom seams. For up the sides, small-ish 1/8" - 1/4" might be nice if it doesn't compromise the strength of the joint.

Then there's the color question (black vs semi-clear). Not sure yet about that...

Can't comment on the silicone but my rimless/braceless 48x18x18in is made from 10mm optiwhite (3/8 starphire in American)
Are you going to shoot for minimalist silicone work?

 

[OllieNZ]

It's more likely my spelling lol.
By minimalist I mean no fillet. It adds no strength it's just easier to fillet than to get a clean joint.

This is a top down of my tank. (please quote me if the picture doesn't show due to Tapatalk being useless)

 

[OllieNZ]

Also the low iron glass is totally worth it and it would be a shame to ruin that with black.

 

[OllieNZ]

From the front.

 

[Codski]

i was looking into building a similar tank. 22"x22"x20" and i was going to use 3/8" glass with some euro bracing. you should be fine.

 

[woodnaquanut]

From the front.

Quote for pic...

 

[woodnaquanut]

It's more likely my spelling lol.
By minimalist I mean no fillet. It adds no strength it's just easier to fillet than to get a clean joint.

This is a top down of my tank. (please quote me if the picture doesn't show due to Tapatalk being useless)

quote for pics

 

[uncleof6]

The so called fillet, better known as an "inner seal" is an integral part of the seam. Though it does not add any significant "strength" (a relative term,) it is important for the protection of the structural seam, and thus should never be omitted for the sake of aesthetics. There is no minimalist look, rather what is required for the longevity of the tank. The "no issues" defense is inadequate when discussing safety/longevity concerns.

9mm - 10mm glass is fine for this tank to be rimless. 3/8" is nominal only, as glass is manufactured to metric standards. Seems folks in the US can't figure out the metric system (so many years later) so the "nominal" is used to keep confusion to a minimum, however, it just creates more...

Structural seams should be ~ 1.5mm (1/16") thick. The thicker it is, generally, the weaker it is, but 3mm (< 1/8") won't kill the tank.

Bottom seam: The bottom structural seam needs to be wider than the side seams. The pressure is greatest at the bottom, and there is no rim to hold it together. This requires the use of a bottom internal euro-brace (~3" wide) with 9 - 10mm glass. (Or a 12mm bottom panel, the tank built with sides around bottom; semi-floated.) Inner seals at this point, does not particularly need to be much wider than the side seals, but there is no reason not to make them wider; like I said it is the structural seam that holds the tank together, with the inner seal offering limited supplemental "strength." That said, if using junk silicone, a wide inner seal can be the difference between a seam that holds, and a seam that pops.

No, the images are not showing up, and IMHO, tapatalk is useless. Though aquanut did not mind reposting the images.....

I don't find starphire glass to be worth the expense at all.

Standard disclaimer: If you have to ask questions as basic as the questions asked in this thread, you need to build smaller tanks, < 20gallon, using 6mm glass, till you no longer need to ask these questions. In the long run you are much better off having someone that knows what they are doing build it (longevity, warranty, knowing it will hold for a year or longer) or purchasing a manufactured tank of similar dimensions.

 

[dkuster]

Thanks for all the replies!

Questions for uncleof6: In your detailed and informative response below, you say that the "structural seams should be 1/16" thick". You are referring to the actual thickness of the silicone layer between where the glass panels meet, correct? Also, as far as using a 12mm panel for the bottom versus using a eurobrace, is one approach inherently better than the other?

Thanks for the help!

The so called fillet, better known as an "inner seal" is an integral part of the seam. Though it does not add any significant "strength" (a relative term,) it is important for the protection of the structural seam, and thus should never be omitted for the sake of aesthetics. There is no minimalist look, rather what is required for the longevity of the tank. The "no issues" defense is inadequate when discussing safety/longevity concerns.

9mm - 10mm glass is fine for this tank to be rimless. 3/8" is nominal only, as glass is manufactured to metric standards. Seems folks in the US can't figure out the metric system (so many years later) so the "nominal" is used to keep confusion to a minimum, however, it just creates more...

Structural seams should be ~ 1.5mm (1/16") thick. The thicker it is, generally, the weaker it is, but 3mm (< 1/8") won't kill the tank.

Bottom seam: The bottom structural seam needs to be wider than the side seams. The pressure is greatest at the bottom, and there is no rim to hold it together. This requires the use of a bottom internal euro-brace (~3" wide) with 9 - 10mm glass. (Or a 12mm bottom panel, the tank built with sides around bottom; semi-floated.) Inner seals at this point, does not particularly need to be much wider than the side seals, but there is no reason not to make them wider; like I said it is the structural seam that holds the tank together, with the inner seal offering limited supplemental "strength." That said, if using junk silicone, a wide inner seal can be the difference between a seam that holds, and a seam that pops.

No, the images are not showing up, and IMHO, tapatalk is useless. Though aquanut did not mind reposting the images.....

I don't find starphire glass to be worth the expense at all.

Standard disclaimer: If you have to ask questions as basic as the questions asked in this thread, you need to build smaller tanks, < 20gallon, using 6mm glass, till you no longer need to ask these questions. In the long run you are much better off having someone that knows what they are doing build it (longevity, warranty, knowing it will hold for a year or longer) or purchasing a manufactured tank of similar dimensions.

 

[OllieNZ]

I have to disagree with the above. My tank is coming up 6 years old now has no bracing around the bottom and no fillet. It was manufactured for a very reputable retailer here in the UK and afaik there's not been any reported issues with their tanks and the aquascaping community here is small enough that issues tend to be well aired. Also the trendsetter in this area ADA use this method on tanks as large as 60x24x24 with the corresponding increase in glass thickness.
As for clarity I certainly notice the difference, I have a standard 6mm float glass tank and the 10mm optiwhite on the same side of the living room and I wish I'd had the front pane of the 6mm tank done in optiwhite.

 

[uncleof6]

I have to disagree with the above. My tank is coming up 6 years old now has no bracing around the bottom and no fillet. It was manufactured for a very reputable retailer here in the UK and afaik there's not been any reported issues with their tanks and the aquascaping community here is small enough that issues tend to be well aired. Also the trendsetter in this area ADA use this method on tanks as large as 60x24x24 with the corresponding increase in glass thickness.
As for clarity I certainly notice the difference, I have a standard 6mm float glass tank and the 10mm optiwhite on the same side of the living room and I wish I'd had the front pane of the 6mm tank done in optiwhite.

It is ok to disagree, and I am certainly glad your tank has not come apart, or had any issues... However, that does not make the tank safe, or advisable under any circumstances, or even a quality build. I really do not care what the builder in UK is doing, ADA, or any other manufacturer does. We are dealing with inexperienced builders on here, not like myself that have been professionally building custom tanks for 20+ years. The inner seal is there to PROTECT the structural seam. It is fine if YOU want to run your tanks with unprotected structural seams. As far as the bottom euro&mdahs;well... there are two kinds of builders in the world: those that see profits first, and those that put quality ahead of profits; there are also many so called reputable builders that don't know the meaning of engineering, let alone employ an engineer. Exactly how you end up with 6mm glass cube tanks that bow like crazy and pop seams...

 

[uncleof6]

Thanks for all the replies!

Questions for uncleof6: In your detailed and informative response below, you say that the "structural seams should be 1/16" thick". You are referring to the actual thickness of the silicone layer between where the glass panels meet, correct? Also, as far as using a 12mm panel for the bottom versus using a eurobrace, is one approach inherently better than the other?

Thanks for the help!

The thickness of the silicone between the glass panels.

Neither is inherently "better" than the other. There are advantages to both. There are also advantages to raising the bottom up inside the sides (floated bottom) Thicker glass, means less work, but a semi-floated bottom is required for it to do any good. Sides on top of bottom, or around the sides, you double the "width" of the bottom seam using a 9mm euro, but it is more work. The wider a seam is, the stronger. So this goes along with glass thickness.

 

[dkuster]

OK, gotcha -- thanks.

In my online research, I saw DIY builds with the sides on top of the bottom, and builds with the sides around the bottom. I read claims that "sides around the bottom" is better because there are no shear forces on the joint. What's your opinion on that?

The thickness of the silicone between the glass panels.

Neither is inherently "better" than the other. There are advantages to both. There are also advantages to raising the bottom up inside the sides (floated bottom) Thicker glass, means less work, but a semi-floated bottom is required for it to do any good. Sides on top of bottom, or around the sides, you double the "width" of the bottom seam using a 9mm euro, but it is more work. The wider a seam is, the stronger. So this goes along with glass thickness.

 

[uncleof6]

OK, gotcha -- thanks.

In my online research, I saw DIY builds with the sides on top of the bottom, and builds with the sides around the bottom. I read claims that "sides around the bottom" is better because there are no shear forces on the joint. What's your opinion on that?

6 one way, half dozen the other. With heavy glass panels, sides on top of the bottom squeezes out too much silicone, and raises questions about how do I prevent that, blah blah, spacers etc. I will say that sides around bottom with 9mm sides and a 12mm bottom is going to be "stronger" than sides on top same thicknesses. But sides on top, with an internal bottom euro, is a toss up.

The weak link with silicone is not the tensile strength (sides around bottom) or the "shear" strength (sides on top of bottom) rather the "peel strength" or adhesive "strength." How the tank is configured has nothing to do with the weak link that will break the chain. It is seam width and thickness. With some silicones (RTV100 series as example) once fully cured and fully cross-linked, the adhesive strength (what holds the tank together) will exceed the tensile strength (lets not get carried away here, that is the theory.)

Just for perspective, every seam in an full aquarium is under both tension and shear forces.

 

[Mark426]

The high end builders that are going with no inner seal are not using silicone or rtv. They are using an industrial grade sealant/adhesive that is different than what we normally have access too. I know for a fact that Elos is not using silicone or RTV any longer for their tanks that have the structural seam exposed to water. Overtime silicone/rtv will fail if the structural seam is not protected from water.

 

[dkuster]

Now this is interesting...

Any details on this "super glue" ?

I wonder if it's something available to DIY'ers...

The high end builders that are going with no inner seal are not using silicone or rtv. They are using an industrial grade sealant/adhesive that is different than what we normally have access too. I know for a fact that Elos is not using silicone or RTV any longer for their tanks that have the structural seam exposed to water. Overtime silicone/rtv will fail if the structural seam is not protected from water.

 

[uncleof6]

Well the way Elos puts it, is what they use is not really a silicone, then they say it is not a standard silicone, that's made for them by a company in Italy, they call it glue, but it is silicone based, is low in "something that evaporates," but "I don't know what that is called," but the silicone... er glue shrinks as it cures... they let it cure for something like two months, (2013 MACNA) translation: a Low VOC RTV silicone polymer, that they are having custom formulated. They are making it very clear that it is proprietary. No miracles here, just marketing hype.