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How to Make a Glass Fish Tank: Diy Basics

Emmanuel is from Nairobi, Kenya and loves researching its history. He is also an artist and likes to share what he knows with others.

An aquarium with a light unit and air pump on top of the glass tank

An aquarium with a light unit and air pump on top of the glass tank

Do It Yourself. Make a Glass Fish Tank

If you have always wanted to have a fish tank, here’s how to make your own. A well done fish tank will be the envy of your friends and visitors It is also believed that looking at a fish tank with fish moving around does not only have a calming effect on you but will also lower your blood pressure. Besides, fish, like all other pets will give you a lot of pleasure when feeding them, watching them grow and perhaps, if you are lucky, breeding.

The first thing you do is to determine the size of fish tank that will be ideal for your space. I would suggest that if you have never kept fish before, start with a small one. It will be easy to make, cost less and besides, the experience will be invaluable. The larger the tank, the better for the fish. But you need to start with a manageable size until you have sufficient experience to maintain a large one. Making a small or large tank isn’t that much different though. The information here is for a 15” X 9” X 9” inches because any mistakes will be will cost you little. But if you follow my instructions carefully, you will be on the road to success.

Your tank should be strong and study so that it would not easily shatter under the pressure of water. You will therefore use quarter inch thick glass and not the thin sheets that are used to frame pictures. Here is a list of the things you will need to assemble for the job:

1. Glass – See detail below on the measurements.

2. Silicone Latex adhesive – get the larger cylindrical tubes that require a gun to push the adhesives. Get ‘clear’ silicone and not coloured. I have however seen someone us black silicone and the effect was good.

3. Masking tape, at least one inch wide.

4. Old newspapers or other sheets of paper for use with the masking tape to mask off large areas.

5. A few sharp razor blades

6. Window cleaning detergent

7. Surgical gloves – use them to handle the silicone especially when you want to spread it with a finger

The Glass

You will need five sheets of glass for the tank. The cover and its supports will be additional three pieces. The first one, 15” x 9” sheet will be the base. The other sheets of glass will be for the two long sides and two short sides. Use the same measurement as the base for the two long ones – 15”X9.” You will also need to plan for a glass cover which will be shorter than the tank so that the gaps on either end will allow air tubing to be inserted when the aquarium is operational. For this you will need two thin strips of glass (1” X 14 ½”) - to support a cover of 8 ¼” X 13.”

The two sheets for the short sides of the tank will have to be half an inch less on one side to fit snugly between the two long ones (see the diagram) i.e. 9”X 8” and ½.” A quarter inch of the width will have been taken by the long glass on the left, and the other quarter by the long glass on the right, totalling a ½ inch.

Below are the glass order details from your local glass dealer.

  • 15” X 9” – Three pieces of quarter inch clear glass; polished edges
  • 9” X 8 ½. ” – Two pieces of the same specs as above.
  • 1” X 14 ½” – Two pieces of the same specs as above for the cover to sit on.
  • 8 ¼.” X 13” - One cover piece of the same specs as above.

The edges need to be polished, otherwise there will be the danger that you could cut yourself as you work. In case you receive glass with unpolished edges and cannot wait to get started, take ordinary sandpaper and go over the edges lightly. This will blunt the sharpness and make them safe to work with.

Now that you have the glass pieces you are ready to join your pieces together to form a container that will hold water securely and for many years.

A silicone tube and a gun to dispense it

A silicone tube and a gun to dispense it

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Working with Silicone

If you do not take adequate preparations, you can end up with a very messy looking tank. You will therefore spend more time masking the glass than joining the glass together. Use masking tape and paper to mask each piece of glass on both sides leaving at least three ½ inch unmasked areas all round the extremities. These exposed glass area is for the silicone. In case you touch the masked area with silicone, the glass will be protected. If you do not mask, you will spend time trying to clean the silicone out with a sharp blade and window cleaning detergent.

Joining the Glass Together

Place the base glass on a table. This is one of the 15” X 9.” Place the Silicone tube in the gun and aqueeze a line of silicone all along the four edges. If you do not have a gun, use a broom stick to push the silicone out then apply it with a finger (that already is gloved). Next, apply silicone on the edges of the glass for the short sides ( see the orange colour in the diagrams).Note that you do not apply any silicone to the pieces meant for the long sides at this stage.

Fitting the four sides of the glass

Fitting the four sides of the glass

Get Help to Hold the Glass

You can ask someone to help you hold one piece for the long sides as you hold the two pieces for the short sides. Place the pieces for the short sides first on the surface of the base glass. Hold them in place as vertically as possible. Now ask you helper to place one sheet of glass for the long side at an angle – base first at 45 degrees, then slowly bring it on the edge of the two sheets for the short sides that already have silicone on the edges. Repeat this action with the remaining sheet. Ensure that the cuboid formed is neat with no protrusions all around the edges of the base glass and the four vertical corners.

Apply Pressure to Joints and use Tape

Apply some pressure to all the joints. Next, get hold of a strong tape and wrap it around the newly formed tank. The type used for sealing cartons is best. Use as much ‘pull’ as is practical to ensure that the tape exerts additional pressure on the joints. Now go over the inside edges of the tank with the silicone and spread it with a finger, making sure that every inch is covered with this new layer. The silicone will reach the edges of the masked areas, which is why you should not have allowed too big a margin in the first place. The thinner the silicone edge, the neater the aquarium will look eventually.

Allow the silicone to set for a minimum of six hours. If you make your aquarium late in the evening, your sleeping hours will reduce any anxiety and you can look at the tank in the morning.

Use tape to secure the glass before the adhesive sets

Use tape to secure the glass before the adhesive sets

Fitting the Cover Supports

Your glass cover will ideally be the same level as the top tank edges when in place. You will therefore need to sink the supports about a ¼ inch from the surface. Peel the masking about a ½ inch down on the long sides. Turn the tank on its side. Mask the thin strips of glass appropriately and apply a thin layer of silicone on three sides – one long side and two short sides. Now push it into place a ¼ depth from the surface. If the piece is a fraction of an inch longer, it will not fit unless with undue force, which will strain the other corners of the tank and cause a leak later. You can use sandpaper to reduce glass that is only slightly longer than desired. Apply some more silicone on the inside to ensure it can hold the weight of the cover glass. Allow about three hours for the silicone to gel sufficiently, then turn the glass over and repeat the process for the other thin strip of glass.

The cover supports are in red to show the small depth of about quarter inch

The cover supports are in red to show the small depth of about quarter inch

Clean the Tank

When the silicone has set completely, remove all the masking. You will be glad that you did the masking in the first place. You may notice that some silicone got to places that were not intended. Use the sharp blade, slanted at less than 30 degrees to coax the silicone away. Be careful not to go near the edges with the blade. You do not want to cause damage that would result in a leaking tank.

Your finished tank and cover. What you need now are the other accessories

Your finished tank and cover. What you need now are the other accessories

Test the Tank for Leaks

Line a table with old newspapers and place your tank on it. Now pour water gently into the tank. Your tank is unlikely to leak. But if somehow, a spot was missed by the silicone and the tank leaks, you will see the newspaper turning wet along the edge somewhere. Follow the water trail until you identify the spot. Use a marker pen to indicate the offending spot on the glass and empty the tank. After drying it thoroughly, mask the areas that should not be smudged with the silicone adhesive and then apply the adhesive firmly by spreading it with a wet finger that is gloved with surgical gloves.

I hope that these instructions have been useful. If you find that you have a knack for making fish tanks, why not make some money on the side as well? There is someone out there who does not want to make their own tank. The plastic moulded tanks are expensive and they are limiting in a way. Lastly, nothing gives more satisfaction than what you make yourself.

Glass Tanks Have Many Uses

You will now need a lighting unit on top of the tank. You will also need gravel, a filter and an air pump before you can think of the fish.

Glass tank uses are many

Here is a list of the uses of a glass tank:

1. Terrarium – where small mammals and reptiles can live.

2. To make an incubator (see my hub on a homemade chicken incubator)

3. To raise chicks

4. To grow plants

Good luck with making glass tanks.

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