Derimming a 5.5g - The Planted Tank Forum
Old 11-02-2011, 07:56 PM Thread Starter
Algae Grower

Join Date: Oct 2011
Location: Redding, Ca
Posts: 95
Derimming a 5.5g

Can you do it and still have the tank be strong enough to hold water?

I see people doing it on here, but I remember I tried to do it on my old 5.5g and I abandoned it when I noticed i could make the side panels of the glass move like the silicone was stretching. Is this normal?
pageerror404 is offline

Old 11-02-2011, 07:58 PM
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Quote:
Originally Posted by pageerror404 View Post
I see people doing it on here, but I remember I tried to do it on my old 5.5g and I abandoned it when I noticed i could make the side panels of the glass move like the silicone was stretching. Is this normal?
no because the force of water at the bottom will rip the silicon then once filled.

pressure is greater at the bottom because u have gravity acting on the vol. of water.
Naekuh is offline
Old 11-02-2011, 08:01 PM Thread Starter
Algae Grower

Join Date: Oct 2011
Location: Redding, Ca
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Quote:
Originally Posted by Naekuh View Post
no because the force of water at the bottom will rip the silicon then once filled.

pressure is greater at the bottom because u have gravity acting on the vol. of water.
I never derimmed the bottom. I noticed it at the top once I filled it. It wasn't like bursting at the seams, but if I pushed it a little bit I noticed the movement.
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Old 11-02-2011, 08:10 PM
Algae Grower

Join Date: Dec 2010
Location: Queens, New York
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Ive derimmed a 5 gallon and a 10 gallon with no problems at all. Anything bigger than that your going to run into issues.
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Old 11-02-2011, 08:51 PM
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simple physics question:

Ok there is a dam of width "b" and water is fille don one side of it to a height h . Now i need to calculate the force on the wall of the dam on the side where water is filled .
This is what I did:

I considered a small layer of water of dx (vertical) at a distance x from top of water surface .

Then:

$\int dF= \int \delta xg (bdx)$

Limits 0--->h on RHS

$F=\frac {b \delta gh^2}{2}$

Therefore the force on the wall depends on :

Width of the dam
The height "h" to which water is filled
Density of water
and g

Except now your F cant exceed the stress point in the silicon b4 it rips.

its too much of a gamble... typically the rimless tanks u see are designed for that much stress, while a rim'd tank isnt.

now dont get me wrong.. im not saying its not possible... its just not all tanks are made the same.. and typically thats why rimless tanks cost a ton more.
Naekuh is offline
Old 11-02-2011, 09:37 PM
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Join Date: Sep 2007
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Quote:
Originally Posted by Naekuh View Post
simple physics question:

Ok there is a dam of width "b" and water is fille don one side of it to a height h . Now i need to calculate the force on the wall of the dam on the side where water is filled .
This is what I did:

I considered a small layer of water of dx (vertical) at a distance x from top of water surface .

Then:

$\int dF= \int \delta xg (bdx)$

Limits 0--->h on RHS

$F=\frac {b \delta gh^2}{2}$

Therefore the force on the wall depends on :

Width of the dam
The height "h" to which water is filled
Density of water
and g

Except now your F cant exceed the stress point in the silicon b4 it rips.

its too much of a gamble... typically the rimless tanks u see are designed for that much stress, while a rim'd tank isnt.

now dont get me wrong.. im not saying its not possible... its just not all tanks are made the same.. and typically thats why rimless tanks cost a ton more.
You may want to look around. There are tons of people on this forum who have derimmed there tank. One even has a 75g derimmed and still going strong. With a 5 or 10 there really are no worries. A 20g Long would also probably be fine. Once you get into taller tanks you may want to have more considerations.

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Craigthor is offline
Old 11-02-2011, 09:54 PM
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After seeing about a million of these threads over time I've come to this conclusion: Anybody who wants to post math equations and propose a tank of ANY size will fail after being de-rimmed is of the personality that just won't de-rim a tank. They are people who just don't take risks unless absolutely and extremely calculated. De-rimming tanks is certainly a risk. I've done several tanks now including 2.5g, 10g, 20L, and honestly I would feel comfortable doing it to a 40B which I plan to do soon.
GitMoe is offline
Old 11-02-2011, 10:30 PM
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Quote:
Originally Posted by GitMoe View Post
After seeing about a million of these threads over time I've come to this conclusion: Anybody who wants to post math equations and propose a tank of ANY size will fail after being de-rimmed is of the personality that just won't de-rim a tank. They are people who just don't take risks unless absolutely and extremely calculated. De-rimming tanks is certainly a risk. I've done several tanks now including 2.5g, 10g, 20L, and honestly I would feel comfortable doing it to a 40B which I plan to do soon.
That's because physics is rarely wrong.. If its wrong you messed up the math... or the theory is messed up which leads to something unforseen.

I am not speaking out of experience... if you guys say its all safe, then it has to be, as i have not been saturated long enough in this hobby to know what is truely safe and what isnt..

However, i do know physics.. and ive been playing with it a lot especially in the areas of PC's and watercooling.

The numbers behind physics says yes its possible, but they also point to there could be risks..

And personally ive spent 2 hours on youtube watching videos of leaking tanks... to the point where it scares me to pieces so id rather not have any risks or minimize the risks as much as possible.
Especially when im telling someone yes its safe, and it could leak.
Naekuh is offline
Old 11-03-2011, 02:34 AM
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"physics is rarely wrong..."

Actually, it's NEVER wrong. Data input can be wrong, laws of Physics...Never!!!

There are to many variables that aren't a constant, different manufators, different, silicone, different glass thickness. There's a good chart for rimless tank construction out on the net. You plug in glass thickness, WxDxH and get a range of safe nights to build at.

I recently disassembled a Plastic framed 75 gl tank that was made in the late 70's my "Metafrane Co." The plastic trim wasn't 1/8" thick. It had a seam in the back of the plastic on the top(not even a complete pc) No center top brace. That tank held water for over 30 years and had been store outside in between uses. All intents & purpose it was a rimless. tHe glass I got from it was all plate 3/8" thick.

Compare that to the some of the current tanks 5/8" plastic top & bottoms, that are molded for strength, top center braces.
DogFish is offline
Old 11-03-2011, 04:08 AM
Planted Tank Obsessed

Join Date: Apr 2011
Location: alexandria, va
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here's a 10g i derimmed few months back..

it still holds water.. i use it as a quarantine tank every now and then..
if still not satisfied, i can post another picture tomorrow with gravel and and water filled to the rim.. from my experience, if a 10g can handle it, a 5g can handle it..
dreamt_01 is offline
Old 11-04-2011, 03:05 AM
Planted Tank Obsessed

Join Date: Oct 2011
Location: Long island Ny
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i seriously just did this today, real easy to take off the rim's. i just pulled them right off than cleaned up excess sil with a brand new razor blade. just be patient and careful, since it is glass.. ill be setting it up tomorrow next to my 20 long under a 4 foot shoplight of 80 watts cant wait to get planting..
Kworker is offline
Old 11-04-2011, 04:52 AM
SCAPEr

Join Date: Jun 2011
Location: Loma Linda, CA
Posts: 2,560
What happened if I derimed 10 gallon into extreme??

Like this? I think I went too far, no silicon at all.

I tested for leaks, no leak! BUT the bowing is scary.

+ I have to find a new light fixture LoL...
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sayurasem is offline
Old 11-04-2011, 05:14 AM
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Quote:
Originally Posted by Naekuh View Post
Except now your F cant exceed the stress point in the silicon b4 it rips.
...
its just not all tanks are made the same.. and typically thats why rimless tanks cost a ton more.
Not arguing with the calculation in the slightest, but without knowing anything about the silicone used in the tank there's no way to say whether it's strong enough or not without trying it out.

I think that the main reason rimless tanks are expensive is that they require more care in their construction for visual purposes rather than the super special silicone that they use. They also are only sold by a few vendors to a fairly select group of aquarium enthusiasts who are willing to pay the premium.

Quote:
Originally Posted by DogFish View Post
"physics is rarely wrong..."

Actually, it's NEVER wrong. Data input can be wrong, laws of Physics...Never!!!
Hope this is a joke. I suppose that physics itself, the fundamental interactions in the universe, cannot be wrong. Our understanding of those interactions, which we might call the laws of physics, are known to be wrong. They are fantastic models and approximations of the things we see in the universe, but there are known problems with them, and phenomena that we cannot account for within them. We've gotten incredibly close to being right, and I detest the people who try to downplay the advances that have been made in science by claiming that there's no reason to trust science as "the answer will just change in 20 years," but close only counts in horseshoes and hand grenades.

In any case, I've got a derimmed 20L sitting on a stand in my dining room that doesn't leak a drop (extreme derimming, as shown with the 10g, all of the visible corner silicone removed.) I've also got a mutant in my basement that for these purposes is a 40B that is rimless and has the silicone heavily trimmed as well. I'd be more concerned about derimming a 2.5g tank than a 10g, honestly, as the 2.5g uses glass that isn't even single strength. I've not seen a 10g use anything but double strength or thicker (1/8".)

I'm not saying that every tank will come out nicely. I'm sure that there are people asleep on the job at some of these factories who did a terrible job of getting the seams right, and it's a near certainty that some will leak. It's a choice for you to make.
jasonpatterson is offline
Old 11-04-2011, 05:41 AM
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I derimmed a 75, after I think 8 months its still going strong

I wouldn't worry about derimming any tank, 75 gallons or smaller.

if you derim a big tank, don't forget to test it for couple of months, just to be sure.

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Old 11-05-2011, 03:06 AM
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The pet store locally has a 125 that they removed the top rim and then added a glass center brace....oh and it's drilled as well which I'm sure weakens it.
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