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How to build a plywood fiberglass tank Part 1

Not very popular in Italy, plywood tanks, are most used for sweet water aquaria, while in the United States they are commonly used for the salt water too.

The winning characteristics of a plywood tank are remarkable flexibility, robustness, lightness, and even lower thermal dispersion, especially if covered with a canopy that is nothing but a cap, a giant lid that closes the tank above.

Often they are made with a single front glass, but also with multiple glasses.

The level of difficulty of construction is medium-high and before venturing into a large tank, let say 2 meters long up, it is advisable to have some experience with medium-sized tanks.

Good skills are required in woodworking and DIY in general. If you are not good with it or poorly carried, better let it go.

You start by doing a general project of the tank, then you need to make others with all the details. I will not divulge by explaining all the small details, such as how to cut the wood or how to assemble the panels or anything like this, that’s for sure you already know 😉

Plywood and fiberglass tank – work in progress ( Photo by Simone Grimaldi)

The first important thing is to have clear ideas about the sizes of wooden panels to buy, which in my case is a 25 mm thick phenolic pine plywood. The term “phenolic” refers to the glue used to assemble the various layers of plywood and guarantees good resistance even for external uses. Obviously it is not our case but knowing that the glue used is suitable for exposure to the weather it makes it even safer even in humid areas like aquariums.

I recommend placing the bottom panel (the horizontal one) underneath all the others, which will instead be resting on it.

With regard to the front frame where the glass resides, it can be done in two ways:

Buy a full wood panel and cut it off internally, creating a frame or use other wood to make strips to assemble. The latter method is cheaper but more risky, because it is not easy to assemble these strips so that they are perfectly planed. It is important that they are, as the glass will force on them, pushed by the pressure of the water. Hence imperfections in the frame could create impermeability problems or even break glass.

Once you have the wood, you can start cutting it according to your project.

To avoid misunderstandings I will always use the same terms and then:

  • Bottom panel is what is below everyone, it is the only horizontal panel.
  • Side panels are the two identical panels that are right and left.
  • – Rear panel is the vertical one that connects the two sides.
  • Front panel is the one that frames the glass.

I recommend you read all the article until the end, before proceeding. It’s important, do it!

Begin by spreading the bottom panel on a flat surface like the floor and position the other pieces (the two side panels and the back panel) on it, without sticking or screwing them, but just to test. Maybe you can help with the clamps to hold them steady and start to realize if there are any problems.

If you feel that everything is perfect remove them and proceed by placing one of the side panels on the floor, and make sure it is perfectly vertical even with the help of a mason’s level (the longer it is the more accurate). Now take the back panel and stick it to the one we have already stood up using lot of polyurethane glue. Now block them, you have two panels standing, glued together and positioned so as to form an ‘L’. With a professional set square make sure they form a perfect right angle and begin to position the clamps.

Before screwing them, it is very important to make a check: using a bubble level verify that they are both perfectly vertical and form an angle of 90 degrees to each other. Once you have put the clamps, check again that nothing has been moved.

Fiberglass (photo by Simone Grimaldi)



When everything is ok, you can screw the steel screws at about 5 cm to each other; Also it is important doing that while the glue is still fresh and not after! To facilitate penetration of the screws and more precision, you can use a drill to make the holes before screwing the screws. Never pierce for a longer depth of the screws itself, or rather … better drill half of it.

There are tools to be applied to the drill that allow to make precise holes, that is, parallel to the wood, avoiding the risk that the tip of the screw will end out of the wood. If you do not have them you can always use a normal drill and maximum precision possible.

Once the first two panels have been locked with the screws, it is best to stop, if you do not have enough clamps to lock the others too. Wait until the glue is hardened (I usually let it dry all night and resume the next day). Do not be in a hurry, adding a panel a day within a few days you will have completed the wooden structure of your aquarium.

It is best to fit the front panel last, once everything else has been assembled. As I mentioned earlier, the best thing is to use a single panel, cut internally to form a frame. The best thing is to rotate the tank so that the rear panel is resting on the floor, leaving the opening where the frame is facing upwards. As always, glue the frame to the other parts and drop down the front panel. Make sure everything is ok and screw as usual.

Let it dry and finally the first important step for building your tank is completed!

In the next article I will show you how to use the epoxy resin, do not miss the appointment!









Appassionato di informatica ed elettronica sin dall'infanzia, sempre in deficit di conoscenza, ho trovato in questo affascinante universo dell'acquariofilia l'argomento che riesce a stimolarmi ma mai a saziarmi abbastanza da diventare noioso!

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