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How To Calculate What Glass Thickness to Use
The basic nuts and bolts of building a DIY glass aquarium for either salt or freshwater use are pretty straightforward:
- Plan ahead.
- Measure accurately.
- Prepare the glass.
- Use the right adhesive.
- Apply the adhesive correctly.
- Install the glass so as to have continuous, bubble-free seams.
The only difference in building a larger tank compared to a smaller one, of say 55 gallons or less in size, is that the bonding process must be near perfect, and the glass thickness must be sufficient to withstand the added water pressure with a margin of error for the unexpected (i.e. Little Johnny winging his new Tonka truck at the Queen Angel in your tank in a fit of rage). You can find instructions and building hints in "DIY Glass Aquarium Plans"
Once the basics of construction are mastered, the biggest concern most people have with building their own custom aquarium is determining the right glass thickness. Using glass which is too thick means spending money you don't have to, and too thin means spending sleepless nights listening for the telltale sounds of cracking glass and running water. There are a few ways in which you can economize on the construction of your new aquarium with little to no loss in strength or utility, but first, let's cover some important factors about glass.Continue to 2 of 4 below.
02 of 04
About Glass Quality, Characteristics & Thickness
The quality of glass is determined by the individual manufacturer's methods and techniques of producing the glass. Testing samples of uniform manufacturer has indicated that the tensile strength runs from 19.3 to 28.4MPa.
Due to limitations of the manufacturing process, the strength of glass can vary, which means a suitable safety factor must be used when calculating glass thickness. The commonly used factor is 3.8. This is not an absolute guarantee, however, it will essentially remove all risk of glass failure other than that created by damaged or very poor quality glass. Scratches and chips in the glass will be the main cause of failure at this point.
You can use our DIY Custom Aquarium Glass Thickness Calculator to get a quick idea of which glass thickness will be required for your tank. Many DIYers think that the 3.8 Safety Factor is a bit of an overkill for their particular tank and location situation (i.e. low traffic in a protected area), and therefore feel comfortable with a lower factor.Continue to 3 of 4 below.
03 of 04
How To Economize on Construction
As an example for economizing, we'll use the basic 4' long x 15" high 55-gallon tank, which is an average size that most of us either started out with or are very familiar with. This tank is normally constructed of 1/4" (6mm) glass, that according to the calculations displayed in our aquarium glass thickness calculator has a Safety Factor of 2.92.
Many DIYers have found that they can increase the Safety Factor for a given thickness and tank size by installing a 4" wide glass brace from front to back of the top of the glass, essentially turning their tank into two 2' tanks, increasing the Safety Factor to 3.38. Rather than go to a thicker glass to increase the Safety Factor, you can economize on construction in this manner.
You can also economize by designing your tank stand so that it fully supports the entire bottom of the tank by using a styrofoam or polystyrene pad between the tank and stand. The pad will keep the tank from failing due to a point load on the glass surface which can be caused by dirt or grit on the stand surface. If the tank bottom is fully supported, you can also use a thinner than normal piece of glass for the tank bottom, since the stand will be adding strength and support, keeping the glass from bending.
Yet another trick is to compute the required thickness for the end pieces of your tank. In all likelihood, the required thickness will be less than the longer front and rear pieces of glass.Continue to 4 of 4 below.
04 of 04
Working With Silicone and Application Tips
Glass preparation and proper installation of the panels is important when you are building your do-it-yourself aquarium, but more so when constructing a larger sized tank. These working with and applying silicone tips can help you avoid common mistakes made when one is working with and applying aquarium silicone.
When applying silicone on the glass, run a continuous 1/4" bead, with no gaps or bubbles.
For the best bonding results, apply only as much silicone as you can work within 3 to 5 minutes because after this the silicone tends to skin over and won't bond well to the glass.
Over the years we found that laying down a bead of silicone on the bottom glass for the rear and one side glass panel, and on one side edge of the back panel, installing the back glass panel on the bottom, then the side panel to the bottom and rear panel worked well to begin with.
When any section to be joined has been set into place, the silicone needs to be smoothed out. This is done by starting at one end of a joined section, pressing the tip of an index finger down into the silicone, then firmly and evenly, without lifting your finger, running it along the full length of the siliconed joint at a slight angle. Now secure the joined section into place with duct tape. There is no need to worry about wiping away any excess silicone that squeezes out from around your finger, as it can be cleaned up or trimmed off once the silicone has fully cured.
The supporting surface of the tank base must be very level. On very large aquariums this can be difficult to achieve, and self-leveling filler may be needed between the polystyrene and the base. This should be applied just prior to fitting the aquarium to the base so that the aquarium’s weight levels out imperfections. Sufficient time must be allowed for the filler to level and fully cure before the aquarium is filled with water.