DIY Silicone and sand background - thoughts?

[kemst]

I am redecorating my display tank and have an idea for a background. The commercial 3D backgrounds are out of my budget - and as I have a lot of tank grade silicone so I thought of making one myself.

It is a small triangular corner tank with 2 sides that need to be covered. both sides are 2ft x 2ft

the plan:

• measure out the required area
• extrude silicone onto a plastic sheet (it will peel off when cured)
• Flatten out to desired profile
• cast sand onto surface and press in to "take"
• Allow the silicone to cure for a week before rinsing and installing.

Options: cut out a plastic mesh to fit the space to use as a template and support for the body of silicone and cast onto this. The sand will be coarse (5mm) and is intend to match the substrate.

I will bed in some metal strips on the back side of the silicone and fix some neodymium magnets to the inside of the tank. This will allow me to replace the background with something else if I choose to later.

I have done a small test run on a sample about 150x150mm and it seems to be ok. I think I will need to make sre the sand is not completely bedded into and covered by the silicone as I am concerned that over time algae will grow on the surface and obscure the sand. If the top layer of sand is not covered then any growth might look more natural.

I can get the silicone and sand for free, and I would like to design it as a "replaceable" insert. I know that it may not look as good as a hard core 3D background - but it will allow me to have something other than bare glass on the back.

Thoughts / advice / comments?

[malawi sand diver]

That's an interesting technique, the only problem would be getting depth, but you could put small rocks under the plastic sheet to create the look of rocks, then once the bump dries, fill the space behing with more silicon. It may be worth investigating using crushed rock aswell to put in the silicon, although sand would be OK. e.g. crushed pummace, crushed granite etc are available at craft shops or from some places that sell rocks. You could even crush some sandstone rocks then seperate the red, brown and yellow colours of the sandstone to make it look like sandstone.

[Gombe]

That's an interesting technique, the only problem would be getting depth, but you could put small rocks under the plastic sheet to create the look of rocks, then once the bump dries, fill the space behing with more silicon. It may be worth investigating using crushed rock aswell to put in the silicon, although sand would be OK. e.g. crushed pummace, crushed granite etc are available at craft shops or from some places that sell rocks. You could even crush some sandstone rocks then seperate the red, brown and yellow colours of the sandstone to make it look like sandstone.

I agree, rather than using just sand you could make your own mosaic. A mixture of glass and rock just depends if the glass is thick enough to handle the load, good luck

[kemst]

I really like the idea of depth, and the stone under the plastic is a great idea. I do also have a small piece of 3D background that I can used as a template and just repeat.

Luckily I have 10mm glass. I like the idea of rocks and may try to incorporate the rock idea. I may need to get more magnets to support the "blob" of silicone and stone at the top. The bottom should be ok as if the heavier stones are bedded in the bottom it should sit ok.

I currently have 10 cartridges of silicone but can maybe get another 20-30. Maybe I'll do 2 versions and see which one works best.

I can get about 5 different types of sand from work, different grades and colours. Maybe I can experiment and see if the prototype is not completely dodgy.

If I figure out how to post pictures I can include them here.

[malawi sand diver]

Sounds great, you probably already have this covered, but make sure its acetic curing silicone, the one that smells like vinegar, as that is the aquarium safe one.

[kemst]

Yep, for sure. Remember also that not all acetic cure silicone is suitable for fish.

I have spoken to the silicone chemist at work and has quite a detailed outline of the different grades of silicone.

We have about 10 grades of acid cure silicone in our range and only 1 is suitable for aquariums. As a general rule if it is "mould resistant" then it also means "will kill your fish" as it has fungicides added (ie will wipe out anything good in your filter and biocycle). There are other reasons why they can be unsuitable (eg some adhesion promoters can make it unsuitable as well)

[malawi sand diver]

Interesting, thanks for the info.