Chapter 1 of 2
How To Cut Down A Glass Aquarium
First let me state a few things. The descriptions include methods/tools I used, and the results I received. Just because something worked/didn’t work for me does NOT mean that you will get the same results. It does mean that this result is possible. Don’t go slamming me with correction Emails and PM’s. Also know: This is TIME CONSUMING and LAYBOR INTENSIVE! DIY for this project will save money, but it will cost time. If you’re short on time, patience or are not trustworthy around sharp edges, buy a prefab tank. I can promise a prefab tank is cheaper than an ER visit!
In the process of compiling the info presented here, I cut down a 65g brick tank, drilled with an overflow, and the frame was not one piece. Tank dimensions 36Lx18Dx24T. I cut it down to 12” tall. Each side had its own section of frame. The glass was 3/8” thick. The other tank cut down was a 90g tank, single piece frames, without overflow. The glass was also 3/8” think and the bottom pane of glass was clearly marked Tempered. Dimensions: 48Lx18Dx22T. I cut it down to 11 tall.
Tools: Break-blade razor(get a good one, Cheap ones break)
Spare break-blade Razor refills
Flat razor scraper (get a good one)
100 pack of spare razors (yes, you read that right)
Steel wool – Coarse works best
Denatured Alcohol(solvent to soften the silicone) – Paint thinner section at Lowes.
Glass cutter(Don’t go cheap on this either)
Large carpenters square(at least as long as the longest cut )
Vegetable Oil(we’ll get there)
Eye protection
Gloves – thick leather
Wet-dry sandpaper – 80 grit – Autozone 8 bucks a pack
Sanding block – a 4” piece of 2x4 works well if you don’t have one
Masking tape
Strap/duck tape
Electrical tape(cheap stuff)
Furniture clamps x 8
1” by 2 or 4” wood, cut at least the height of the cut down aquarium (8 required)
1”x1” Cut precisely(2-4 the width of the tank between panes(measure while disassembling, without frames) and 2 the Length of the Tank(again, measure between panes before disassembling)
1”x1”(2x4 work too), cut 8” Wider than the finished tank, front to back(3 required)
Several small blocks of 2x4(only needed as spacers, so length is not important(mine were 4”)
Sharp chizle/narrow screw driver
Silicone
Calking gun
Paper Towels(2 rolls at least)
CHEAP wide measuring tape(this will be ruined during this process, so don’t spend a lot)
Aquarium without Tempered glass sides(included for reasons that may or may not be obvious)
Steps: Remove Tank Frame, top and bottom
Clean all panes to be cut thoroughly inside and out
Clean frames
Cut glass
Sand edges
Tape tank back together
Tape off seams inside
Seal tank
Leak test
Removal of the tank frame requires a lot of time, caution and quite a bit of patience. Most tank frames are siliconed in place between the glass on all edges. This process can take a while, so don’t plan to have it done in 30 min. Using the Break-blade razor, slide under and behind all the frame/glass contact surfaces to cut the silicone. Apply a slight pressure away from the glass(ie UP) so you can see if you’re loose yet. Some tanks have a slight inside lip which makes getting underneath inside impossible. IF that’s the case, cut as much of the outside silicone as possible, then using a board and rubber mallet, knock the frame up a little at a time, going around many times. Don’t be gentle, but be sure you are applying all the pressure against the frame and not the glass. This will separate the frame, but only after the silicone along the sides has been cut.
Now we take the glass apart. Using a break-blade razor, I first went and cut as much of the visible silicone out of each of the corners as possible. To separate the panes I tried multiple methods, and I can tell you that getting to the silicone seals between two panes of glass, ie corners, is a challenge. I tried strait razors, the break-blade razors, and both were too thick on the 2 aquariums I was doing for this project. What I finally found that worked is a measuring tape. A 1” wide measuring tape is thin enough, sharp enough, and rigid enough to literally push down between the panes without putting too much pressure. Its likely that the measuring tape will get bent/torn once or twice during this process, so gloves and a cheap measuring tape are essential. With break-blade razors I could get the cut started at the top, but it would get stuck at about 6” down. If this happens, be very very gentle removing it. I wiggled it to try and get it unstuck and it caused a clamshell. I started with the Front pane of glass because it already had a couple chips.
Clean the glass thoroughly inside and out. Glass over ¼” is tough to cut, and scoring on both sides may be required. The cleaner the glass, the better the chances the cut will be clean. Now we get to the edges, where the old silicone was. Using strait razors, with a scraper, remove as much silicone as possible. Change blades often. In my experience, a razor becomes too dull to get very close after about 12” of edge. Once that’s done, using steel wool, go back along the edges to get the remaining silicone off. I know some are screaming at me(NOOOO! Steel wool will scratch the glass!!!) Short answer, No it wont. Glass is harder than steel. And even if it did pick up a particle of dust/sand and make a scratch, these will be under silicone anyways. I kept the edges wet with alcohol during this to make it easy to see areas that needed attention(denatured alcohol will both soften the silicone, and bead away from it) Get all the silicone off. Take time and get this right. If there is any silicone left, the glass may not break strait and the new silicone used to seal the tank will not seal correctly.
While cleaning the Glass, remember to clean all the silicone off the frames. Using a razor and or sharp flat screw driver and steel wool, get the frame good and clean.
Glass cutting time! If you don’t know how to cut glass, if you have NEVER cut glass(ME), or if you are cutting glass thicker than ¼”, I seriously advise contacting a local glass company and get the job done for you. Most places will charge $10-$20 per cut. This is a good safe solution. A friend at work did it for me for the price of lunch. If you’re cutting the glass yourself, do use a quality cutter, a good carpenters square, and vegetable oil to lube the cutting wheel(veg oil is not toxic and is easy to remove after cutting with soap and water)
How To Cut Down A Glass Aquarium
First let me state a few things. The descriptions include methods/tools I used, and the results I received. Just because something worked/didn’t work for me does NOT mean that you will get the same results. It does mean that this result is possible. Don’t go slamming me with correction Emails and PM’s. Also know: This is TIME CONSUMING and LAYBOR INTENSIVE! DIY for this project will save money, but it will cost time. If you’re short on time, patience or are not trustworthy around sharp edges, buy a prefab tank. I can promise a prefab tank is cheaper than an ER visit!
In the process of compiling the info presented here, I cut down a 65g brick tank, drilled with an overflow, and the frame was not one piece. Tank dimensions 36Lx18Dx24T. I cut it down to 12” tall. Each side had its own section of frame. The glass was 3/8” thick. The other tank cut down was a 90g tank, single piece frames, without overflow. The glass was also 3/8” think and the bottom pane of glass was clearly marked Tempered. Dimensions: 48Lx18Dx22T. I cut it down to 11 tall.
Tools: Break-blade razor(get a good one, Cheap ones break)
Spare break-blade Razor refills
Flat razor scraper (get a good one)
100 pack of spare razors (yes, you read that right)
Steel wool – Coarse works best
Denatured Alcohol(solvent to soften the silicone) – Paint thinner section at Lowes.
Glass cutter(Don’t go cheap on this either)
Large carpenters square(at least as long as the longest cut )
Vegetable Oil(we’ll get there)
Eye protection
Gloves – thick leather
Wet-dry sandpaper – 80 grit – Autozone 8 bucks a pack
Sanding block – a 4” piece of 2x4 works well if you don’t have one
Masking tape
Strap/duck tape
Electrical tape(cheap stuff)
Furniture clamps x 8
1” by 2 or 4” wood, cut at least the height of the cut down aquarium (8 required)
1”x1” Cut precisely(2-4 the width of the tank between panes(measure while disassembling, without frames) and 2 the Length of the Tank(again, measure between panes before disassembling)
1”x1”(2x4 work too), cut 8” Wider than the finished tank, front to back(3 required)
Several small blocks of 2x4(only needed as spacers, so length is not important(mine were 4”)
Sharp chizle/narrow screw driver
Silicone
Calking gun
Paper Towels(2 rolls at least)
CHEAP wide measuring tape(this will be ruined during this process, so don’t spend a lot)
Aquarium without Tempered glass sides(included for reasons that may or may not be obvious)
Steps: Remove Tank Frame, top and bottom
Clean all panes to be cut thoroughly inside and out
Clean frames
Cut glass
Sand edges
Tape tank back together
Tape off seams inside
Seal tank
Leak test
Removal of the tank frame requires a lot of time, caution and quite a bit of patience. Most tank frames are siliconed in place between the glass on all edges. This process can take a while, so don’t plan to have it done in 30 min. Using the Break-blade razor, slide under and behind all the frame/glass contact surfaces to cut the silicone. Apply a slight pressure away from the glass(ie UP) so you can see if you’re loose yet. Some tanks have a slight inside lip which makes getting underneath inside impossible. IF that’s the case, cut as much of the outside silicone as possible, then using a board and rubber mallet, knock the frame up a little at a time, going around many times. Don’t be gentle, but be sure you are applying all the pressure against the frame and not the glass. This will separate the frame, but only after the silicone along the sides has been cut.
Now we take the glass apart. Using a break-blade razor, I first went and cut as much of the visible silicone out of each of the corners as possible. To separate the panes I tried multiple methods, and I can tell you that getting to the silicone seals between two panes of glass, ie corners, is a challenge. I tried strait razors, the break-blade razors, and both were too thick on the 2 aquariums I was doing for this project. What I finally found that worked is a measuring tape. A 1” wide measuring tape is thin enough, sharp enough, and rigid enough to literally push down between the panes without putting too much pressure. Its likely that the measuring tape will get bent/torn once or twice during this process, so gloves and a cheap measuring tape are essential. With break-blade razors I could get the cut started at the top, but it would get stuck at about 6” down. If this happens, be very very gentle removing it. I wiggled it to try and get it unstuck and it caused a clamshell. I started with the Front pane of glass because it already had a couple chips.
Clean the glass thoroughly inside and out. Glass over ¼” is tough to cut, and scoring on both sides may be required. The cleaner the glass, the better the chances the cut will be clean. Now we get to the edges, where the old silicone was. Using strait razors, with a scraper, remove as much silicone as possible. Change blades often. In my experience, a razor becomes too dull to get very close after about 12” of edge. Once that’s done, using steel wool, go back along the edges to get the remaining silicone off. I know some are screaming at me(NOOOO! Steel wool will scratch the glass!!!) Short answer, No it wont. Glass is harder than steel. And even if it did pick up a particle of dust/sand and make a scratch, these will be under silicone anyways. I kept the edges wet with alcohol during this to make it easy to see areas that needed attention(denatured alcohol will both soften the silicone, and bead away from it) Get all the silicone off. Take time and get this right. If there is any silicone left, the glass may not break strait and the new silicone used to seal the tank will not seal correctly.
While cleaning the Glass, remember to clean all the silicone off the frames. Using a razor and or sharp flat screw driver and steel wool, get the frame good and clean.
Glass cutting time! If you don’t know how to cut glass, if you have NEVER cut glass(ME), or if you are cutting glass thicker than ¼”, I seriously advise contacting a local glass company and get the job done for you. Most places will charge $10-$20 per cut. This is a good safe solution. A friend at work did it for me for the price of lunch. If you’re cutting the glass yourself, do use a quality cutter, a good carpenters square, and vegetable oil to lube the cutting wheel(veg oil is not toxic and is easy to remove after cutting with soap and water)