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Artificial Rock Walls and Terraces - By NetMax
This structure (figure one) went into a built-in 65g planted African cichlid
tank with very hard & alkaline water conditions. This fish-plant-water
combination was going to be hard on plants, so I went with a system of
double pots for each plant. Lower pots are surrounded by dolomite, upper
pots (planted) use fluorite. A similar egg-crate grill was used to protect
the root systems, and a foam liner kept the red fluorite from mixing with
the white dolomite. Some planting goes directly into the structure. A spot
in the center is reserved for a large Amazon sword plant, and indents on
both sides were made for Java ferns. To raise the gravel up around the
pots, the structure is a 4" high wall. To reduce maintenance, I've created
an automated gravel vacuum, by integrated some UGF plates into the structure
and connecting them to a Fluval canister. An Eheim canister does the main
filtration.
Materials Used
- GE clear Silicone for Doors & Windows
- West System Resin 105
- West System Hardener 206 (205 ok as well, but less working time)
- DOW extruded Styrofoam (better than expanded polystyrene used for packing
materials)
- various wire wheels
- various rasps & files
- modified hack-saw blade
- plastic pots (Canadian Tire) siliconed to Plexiglas base
- 3 UGF screens
- plastic drywall anchors
- plastic egg crate
Red trims were to add surface area for siliconing to
glass bottom. Holes in Styrofoam mark locations where anchors were imbedded
to lock siliconed layers together. Exposed anchor heads are to increase
silicone adhesion to underside (silicone flowed around the anchor head), see
Figure 4.
The following assembly order can also be used for making Styrofoam
backgrounds. The biggest concerns are to seal any paints used, with the
epoxy resin, and to ensure there is sufficient silicone bonding to
counteract the buoyancy of the Styrofoam. Water weighs about 55 lbs/cu.ft,
where Styrofoam weight about 1.5 lbs/cu.ft, leaving over 50 lbs/cu.ft of
buoyancy to overcome.
Assembly procedure:
- Build cardboard template (tank bottom or back wall for a background).
Mark all interferences & clearance needs.
- Obtain materials (ie: extruded polystyrene, sand(s), paints, rocks to
match etc). Use the thickest Styrofoam available to avoid stacking layers
(4" is max, when available in H/W stores). I siliconed my layers together.
Next time I will try putting epoxy on both sides and while tacky clamping
together.
- Rough cut and dry fit into empty aquarium periodically. A design on
paper helps tremendously.
- Cut, file and trim as desired. Check fit with any accessories (siphons,
heaters, filter outlets).
- Pass a heat source (hot air gun or propane torch) over all exposed areas
to seal surface. Exercise caution, as Styrofoam is flammable & toxic.
Careful heating will only cause it to melt into itself slightly.
- Paint. I used white acrylic latex primer but this is not overly
critical, if it is fully dry, and then covered over by the epoxy resin.
Color can match other rocks used. Darker colours look natural faster but
darken the tank. Keep fish colours in mind for contrast. Try to stay close
to the colour(s) of the sand which will be used.
- Apply 1st coat epoxy.
- When dry, apply 2nd coat epoxy and sprinkle sand over the structure.
- Repeat epoxy/sand until satisfied with results. My 1st coat was 100%
white sand, and each following coat had more brown sand mixed in until the
4th coat was 50/50 white/brown sand, imitating sandstone. Without colour
layering, 2 or 3 coats should be sufficient.
- Prepare surfaces for siliconing. For backgrounds, it may be sufficient
to only clean the glass, and use a generous bead of silicone at the
perimeter and across the middle. However, I think that this would be
insufficient to overcome the buoyancy of a structure at the bottom of the
tank. The Styrofoam would lift leaving the silicone on the bottom glass.
To prepare the underside of the structure, I used 3 methods. Exposed
Styrofoam was roughened with a rasp and given 2-3 coats of epoxy (which
provides better adhesion than Styrofoam in my tests). I install plastic
anchors so they were 1/4" above a countersink and flush with surface (the
silicone would flow around these providing greater adhesion). Maximize
surface contact areas to silicone. Referring to Figure 3, I used red
plastic trims and filled areas of the UGF screen with epoxy coated Styrofoam
(not shown, see dashed lines).
- Dry fit and determine how the structure will be held, while the silicone
cures (ie: clamps).
- Apply silicone (clear herbicide-free adhesive, not sealant) to
structure, press into place, and remove. By looking at the pattern of
silicone left on the glass, add more silicone directly to the glass to fill
any gaps in perimeter bead, or wherever needed.
- For aquarium use, I would allow 4-7 days for curing time.
- Rinse, by adding water, and then changing it after 1 day.
Note: For bottom structures, a concrete base plate can also be used, instead
of siliconing to tank bottom. Run plastic anchors into Styrofoam underside,
and seat them into a curing cement-sand mix in a temporary mould. This is
more suitable for smaller structures which can be intricately carved with
caves, but are still removable for catching the fish. This is next on my
aquarium project list.
I can be contacted at computeralias@hotmail.com for
any updates.
NetMax
View of the finished project
Article Survey
Your feedback on this article would be greatly appreciated. All feedback is
anonymous, so please, be honest. Your input can help me create better content.
If you have any questions about this article, or if you feel that something is
incorrect or missing, please let me know via email at cgadd@cfxc.com
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