Glue, Silicone, or Both?

[SkyHook11]

First time poster. I'm hoping some more experienced posters can help answer a couple questions. I could not find a reasonable priced amphibian aquarium so it will be a DIY project. The dimensions are 27w x 9d x 7h (inches).

The first question is related to gluing the glass together. I know that a non-toxic sealant is typically used for holding the glass together. But I am wondering why no one uses both glue and sealant? For bonding, that would be to apply glue to the edges of the glass where they butt together. When that cures, then apply the sealant on the inside of the tank where the sides and bottom met each other. Is that overkill?

This is probably a dumb question, but here goes. Can I use a electrical tape for bracing? This size tank probably doesn't need it, but this my first DIY tank and my wife insists on dry floors. The idea would be to wrap the top and bottom sides of the tank with a continuous strip of tape then put another wrapping over the first one.

 

[Colin_T]

Hi and welcome to the forum

Aquarium glass silicon glues and seals up the edges so you don't need two separate adhesives. Just buy some glass silicon from the hardware and make sure it is suitable for aquariums, then glue away to your hearts content.

Make sure the glass is clean and free of grease, oil and dirt. Wash it with warm soapy water and rinse well before gluing, or use alcohol to wipe the glass down.

Use silicon outdoors or in a well ventilated area and don't stick your head in the tank and inhale the fumes because you will pass out.

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As a general rule you use glass strips to act as cross members and support straps. However, on a shallow tank (7 inches high), you probably won't need support straps if it is for amphibians and isn't going to be filled up with water.

If you use thicker glass it won't flex or bow outwards and you can get away without support straps. 5 or 6mm thick glass would be ample for that size tank and you would not need support straps.

If you are ordering the glass then I would suggest making the tank bigger than your dimensions. I would go 27-30inches long x 12inches wide x 12 inches high.

Another option is a plastic storage container. You can get them cheap and they make great frog, newt and lizard habitats.

 

[Jeremy180]

First time poster. I'm hoping some more experienced posters can help answer a couple questions. I could not find a reasonable priced amphibian aquarium so it will be a DIY project. The dimensions are 27w x 9d x 7h (inches).

The first question is related to gluing the glass together. I know that a non-toxic sealant is typically used for holding the glass together. But I am wondering why no one uses both glue and sealant? For bonding, that would be to apply glue to the edges of the glass where they butt together. When that cures, then apply the sealant on the inside of the tank where the sides and bottom met each other. Is that overkill?

This is probably a dumb question, but here goes. Can I use a electrical tape for bracing? This size tank probably doesn't need it, but this my first DIY tank and my wife insists on dry floors. The idea would be to wrap the top and bottom sides of the tank with a continuous strip of tape then put another wrapping over the first one.

Hello, and welcome to the forums.

The main reason Silicone and not glue is used for aquariums is that it adheres to glass better than practically any other compound.

When you select your silicone, be sure to use aquarium safe silicone, or at least silicone rated as food safe, if getting it from a hardware store.

I read the Msds of a product claiming to be 100% silicone, and found a petroleum compound, added as a mildew retardant. This was listed on several websites as harmful to aquatic life.

As to the electric tape, it would be useful for holding the glass in place until the silicone cures, (Personally I would double the recommended curing time to be safe), but while maybe looking good, would not add any structural support, so your tank would be considered "frameless"

It is recommended that you assemble the sides of a frameless tank to rest on top of the bottom glass, then place the tank on top of a sheet of padding.

For frameless tanks under 10 gallons, a foam fatigue mat at least 1/4" thick will do for padding, but for larger tanks, Styrofoam board works better.
These are often available in the insulation section of most home improvement stores, and to improve appearance, a strip of electric tape, a permanent marker or if it is water based, paint will do for coloring it black. Please note: Paints that are not water based can dissolve the Styrofoam.

This is to smooth out any unnoticed imperfections that could otherwise cause pressure points leading to cracks, leaks, or in the worst case, catastrophic tank failure.

A note For anyone reading this in the future: Tanks framed with black plastic Trim are assembled differently, and designed to rest on the bottom frame only, and a pad thicker than the space given between the bottom trim and the bottom glass can flatten enough to put upward pressure on the bottom pane of glass, which can put severe stress on the bottom seal in a framed tank, due to the difference in design.

 

[Jeremy180]

Hi and welcome to the forum

Aquarium glass silicon glues and seals up the edges so you don't need two separate adhesives. Just buy some glass silicon from the hardware and make sure it is suitable for aquariums, then glue away to your hearts content.

Make sure the glass is clean and free of grease, oil and dirt. Wash it with warm soapy water and rinse well before gluing, or use alcohol to wipe the glass down.

Use silicon outdoors or in a well ventilated area and don't stick your head in the tank and inhale the fumes because you will pass out.

------------------------
As a general rule you use glass strips to act as cross members and support straps. However, on a shallow tank (7 inches high), you probably won't need support straps if it is for amphibians and isn't going to be filled up with water.

If you use thicker glass it won't flex or bow outwards and you can get away without support straps. 5 or 6mm thick glass would be ample for that size tank and you would not need support straps.

If you are ordering the glass then I would suggest making the tank bigger than your dimensions. I would go 27-30inches long x 12inches wide x 12 inches high.

Another option is a plastic storage container. You can get them cheap and they make great frog, newt and lizard habitats.

Agree with most of what you posted, Colin, except that in my humble opinion, rubbing alcohol is a better cleaner for prepping for silicone, as it does not leave a residue that could interfere with the silicone bonding with the glass, like some soaps can.

I would personally also let any plastic containers not designed for aquatic life sit full of water 24 hours, then completely draining the container before filling it for aquatic animal purposes.

My reasoning is that many new plastic containers intended for food use recommended washing before using them, I am assuming this is to remove any potential residues from the factory.

 

[SkyHook11]

Colin/Jeremy> Thank you so very much for your advise. I started the project today and am using a 100% GE Silicone that is food safe so should be OK for the tank.

I wished I had known about the idea of using plastic containers. I could have saved myself $40 in glass. But that's a great idea for my next project which is a turtle tank.

This tank is going to be a replacement for a 10 gallon fish tank where I now keep an aquatic frog. The frog is hyper and keeps bumping into the glass ends of the tank so I thought a bit of extra length might help. Since it already is in that tank, I am taking my time with extra curing for the silicon on this new one

I also appreciate the suggestion for a Styrofoam fatigue mat on larger tanks. I have a 55 gallon freshwater tank. The next time it is emptied and cleaned, I will put one under it.

Now if this newbie could offer a tip. I bought four 90 degree corner clamps for $10 total and used them to rock steady secure the four glass sides after I applied silicone. I did use painters tape, but I doubt it was necessary.

Again, thank you for your help.

 

[Colin_T]

Food safe silicon doesn't mean anything. You want a silicon that is designed for glass and suitable for aquariums. Some silicons don't stick to glass well and come apart after a short time in water. Make sure you use a glass silicon suited for aquariums.

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If you are going to get turtles, then most plastic storage containers won't be big enough and you should make a pond instead. You can make indoor ponds from railway sleepers or any wood and line them with a plastic or rubber pond liner. This will give the turtles space to move about.

Just make up a wooden frame and put if on a solid floor (without carpet under it). Put a layer of polystyrene foam or foam rubber on the bottom of the frame to insulate the bottom. If you are keeping tropical turtles then do the same to the sides. Use 2 inch thick foam or thicker if possible. You are basically making a big esky (like what you use to keep drinks cool) so the water temperature remains stable.

Once you have made the frame you line it with foam and then rubber or thick plastic pond liner. Rubber is better for turtles because they can get a better grip on it when moving about the bottom. It is also thicker and less likely to get holes in. But it does cost more.

You can use plastic, Perspex or glass to make a ledge/ shelf in the pond for the turtles to come out of the water and sunbake. Then fill the pond with water, add dechlorinator and get the filter going. Add turtles and your good to go.

 

[pov]

you can wet down your silicon to improve curing times, it cures from moisture although it is really important that the silicon gets a skin first which can be anything from ten minutes to an hour . " if you submerge silicon straight away in water it turns cloudy and brittle , but if you add moisture at the end of the process you get a better longer lasting product also add soapy water to make the droplet size smaller " I learnt this from making silicon moulds, and also I agree about using the silicon for aquariums e.g it may have a self oiling compound that stops the sealing from drying out so it will always leach this chemical for it,s life span , I have used tanks with normal silicon and it doesn't kill anything but the few ppm of chemical that it does have is another toxin that you will need to consider when you want the perfect conditions in you aquarium.