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how can I cut the top off a 5 gallon glass carboy to use for a fish tank? Answered



8 years ago

The answers given so far are on the right track. If you are using a glass cutter wheel, you need to build a balance apparatus to ensure that the scoreline is completely even.

The method of heating and cooling is the scoreline is probably the safest--tie a piece of metho-soaked cloth around the scoreline and set it alight, then run a fresh icecube around it immediately the flame falls off. The more traditional method of gently tapping the glass on the inside of the scoreline will not give you the straightest/safest cut.

In any case you will probably have to put protective stripping over the cut, or take it to a glazier for grinding--in which case, I would let the glazier grind the whole thing in the first place--his risk, not yours.

PS: Why not experiment with a plastic one first? You may be saving some land-fill.


9 years ago

Get a glass cutter, score around the top edge and then heat the glass around the score. When the glass is a little hot dunk it in cold water and repeat the heating and dunking until it cracks.


Answer 9 years ago

On smaller objects I've also seen folks run an ice cube along the heated score line to induce the stress needed to create the crack.