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My 75 gallon derimming project.

41K views 79 replies 45 participants last post by  Desert Pupfish 
#1 · (Edited)
I started removing the rim on a 75 gallon today.
I got the top rim off and tomorrow I will start to remove the bottom rim.
I will cut 3 small pieces of glass and place them in the middle and sides so the glass won't bend.

It took me 30 min to to take the top rim off and clean the silicone.
Hope the bottom goes that fast and well too.

Here are some pics:








 
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#8 ·
I will derim it for the heck of it.
I just want to see if it works, if it don't, I wasted $50 and I flood the garage.
I can still put some more glass braces in it on the bottom under the gravel.
I just want to try this, if it works for me, it works for everybody!
what do you guys think about the braces under gravel?

I think his whole project should work without braces. I had a 400 liter in Belgium without any braces and the glass was only 3 mm thicker... So I think this should work.

thanks for the replys

If it don't work, I have a break nearby to bend metal, so I can save the tank ;) but I believe this should work if my math is correct!
 
#9 ·
The biggest issue if the height of it as well as the quality of silcon and workmanship when making a rimmless tank. Standard factory tanks are built cheaply assuming that the rim will hold it together, but rimless are not. what were the dimensions of the 400l tank you had? The height was the same? 3mm difference in glass thickness is a lot.
A 120X60X45cm tank can be built in 8mm glass (not extremely safe but it has been done)
A 120X60X55 build in with the same glass will fail!
A 120X60X50cm tank can be built in 10mm glass
A 120X60X55cm tank with the same glass will fail!
A 120X60X60cm tank can be built in 12mm glass
A 120X60X65cm tank with the same glass willl fail!

Height not lenght is a big factor!

Most manufactors state the braces on the bottom help in holding the bottom seam together but it does nothing to prevent the top side seams from coming apart with the accidental pressure of cleaning algae too hard, or poor silcon and/or workmanship. Your better of to atleast put small 45 degree triangle corner brace on the top of the of the tank (like eurobraces, but only in the corners, to protect the seams, though will do nothing for center bowing).
 
#10 ·
I think theoretically a narrow strip running the length of the tank, siliconed inside the top at the front and back, siliconed to the front and back as well as on the ends, will be far stronger. That would eliminate the bowing problem too. This would be a modified Eurobrace. Siliconing the ends of such strips would be very difficult, so you could use glass triangles that extend close to the center of the front and back, but only 2-3 inches along the ends, would work well too. To avoid the sharp end of the triangle the ends could be lopped off, probably a good idea for any triangular brace.
 
#11 ·
Also a note that length does matter for bowing. If you make a side too long without enough bracing, you're just as screwed as if you use the wrong thickness glass for the height.

The corollary is that you can theoretically brace every 3 inches and have an ugly looking tank with the thinnest possible glass.

Bottom line, make sure you test the tank for a while with water and check bowing to see how much stress you're putting on the glass.
 
#16 ·
Just mounting glass for bracing doesn't just make it "structurally sound".

Thus my first comment in the first reply:

Did you do some homework on this before you did it? Never heard of anyone derimming a tank this size before.

Good luck, I hope its a successful project.
The short term is not the real problem, I think its the long term survival that may be the issue. Interesting to see someone experiment.
 
#15 ·
Yesterday I had a hangover and today I cleaned the yard.
I will return to the project one of the next days.
If the project fails, I will post it for sure with pics.
 
#20 ·
I did a little bit of homework on this over the last year.
I read people doing it on 5, 10 and 20. But I always read that no one ever tried to derimm bigger sizes. Everyone is scared to start at a project like this.
So why don't I try it as fist and show you guys what can go wrong or can't go wrong. I think when this works, there will be a lot other people that will follow or still be skeptic (but yeah, I still have to finish ans prove lol).
This is just for the science, if it works, good for me, I guess... If it don't, I wasted some time, some money and probably spilled a lot of water over the floor "wife yelling :D " and some cleanwork.

I will keep all the comments in mined and thank you for them all, I appreciate it!

I will probably go with the 4 corner triangles and one brace in the middle.
What brand silicone from Home depot or Lowes was aqua and fish proof again ? Or should I go with a better brand?

Thx
 
#21 ·
my only concern with derimming a tank this size and it working for you is there are a lot of other things to consider. a brand new tank derimmed will probably do better than a 10 year old tank.

i think you're going to want to set up a containment zone, to at least capture any glass. 75 gallons of water in a garage is not a huge deal (especially if it is detached) but 75gallons and shattered glass being moved where ever the water decides to move it is.

something as simple as a parameter of wood studs (2x4) would probably work just fine.

i think people have derimmed larger than 20gs, it just seems they use those as rips
 
#26 ·
+1 hoppy

I think this will be fine I would install corner braces and build a removable timber centre brace. If you cut a piece of timber a little wider than the tank with a groove at either end to slip over the glass. Then when you fill it with water if the sides flex you won't be able remove the timber brace and it won't smash the tank
 
#27 ·
I've been thinking about that. But wood flexes, and I'm picturing the wood either cracking or literally popping off. A bonus would be that wood also compresses some, so it wouldn't create hard points against the glass like a more rigid material would, if there were any inconsistencies along either surface (there probably would be).
 
#29 ·
It's raining today... and the project is outside.
Maybe tomorrow. And I still have to order my glas trims.
 
#30 ·
I removed the bottom trim and filled it with water.
The middleglass of the tank expanded 7 mm.
I think its trustable without the trims.
Here are some pics:





 
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