Re: What do I use to stick rocks together ?

[NetMax]

"Alan Silver"
> wrote
in message ...
> Hello,
>
> I am in the process of building a stand for a new 220 litre tank. This
> is going to have a large pile of slate as a backdrop. This is going to
> be no more than a few inches front to back, but cover most of the width
> and height of the tank to provide a dark background and some hiding
> places in the spaces.

Stacking stones will often create zones where fish can get trapped, food
gets caught, or water stagnates. This is not a problem unless the stones
are fastened together as you are attempting. Just be aware of some of
the pitfalls of permanent installations, and keep in mind the size of the
fish which will be going in & out of any caves, whether they could get
trapped or damaged, and whether you would ever need to net them out
someday ;~)

> Now obviously just piling up the rocks is a sure-fire recipe for
> disaster (like when they all fall over !!). I have read that you can
> stick them together with silicone. Is this the same stuff you buy in
DIY
> shops for sealing round baths, etc ? If not, what do I need ? Does this
> provide a firm seal, or would the rocks still need fixing more firmly ?

GE silicone for door & window has no fungicides and is aquarium safe. I
would not use it to hold aquarium glass together, but I do use it to hold
things together underwater. The quality of the seal will depend on the
surface of the materials (dry, not dusty, somewhat porous is good) and
their weight relative to the surface area of the silicone being applied
(flat slate pieces bond easily, use black silicone).

> Also, I read that it is a good idea to stand such a rock formation on a
> thin sheet of expanded polystyrene to minimise chances of the glass
> getting broken. Is this also a good idea ? I presume it goes under the
> substrate.

Placing the rocks over a styrofoam sheet is always a good idea. You
might also want to fasten the stones together in groups, so they can be
removed (for catching or releasing trapping fish). Fasten them into
groups of 3 or 4. Assemble method is to dry fit them into a cardboard
box (bottom, back and sides only, cut to the size of your aquarium
interior), photograph and print out the picture, disassemble and
re-assemble with silicone in groups following the picture, age for about
a week, rinse and then place into aquarium. Space the structure from the
tank sides either far enough away so ingress/egress is not restricted, or
close enough that ingress is impossible. The last thing you add is the
substrate.

If you are interested in making slate backgrounds with no caves, each
piece horizontal, I posted an assembly method which used a wooden mold
and concrete to hold the slate in the required pattern. If you can't
find it in the archives, let me know and I'll reprint it.

cheers
NetMax

> TIA for any help.
>
> --
> Alan Silver
>

[NetMax]

"Alan Silver"
> wrote
in message ...
> <snip>
>
> Excellent advice, thanx.
>
> >If you are interested ....... but if you can either repost, or find
> a link to it I would be really grateful.

> --
> Alan Silver

re-posting 3 articles.. keep in mind that permanent structures with caves
making catching cichlids problematic. These plans don't provide much in
the way of caves, just a slate background, but it could be modified as
you require.

reprint on leeching concrete:
The article I'd referred to was from the Advanced Aquarist Guide, 1969
Dr. Feroze N.Ghadially (hardcopy). I've copied the essentials below. My
understanding of concrete's leaching effect is that it is temporary, and
can be removed in a relatively short time using water changes 3-4 weeks,
or starting with acid and them going to water. I've not gone through the
exercise, so this data comes from others. Perhaps some posters can share
their personal findings. The time required for the concrete to become
neutral in the water would be somewhat determined by the cement recipe
(amount of limestone in mix?), and the thickest points (I would expect
thin slabs would finish leaching the quickest). If the rocks chosen for
the mould described below, do not leach, then the only concern is the
cement foundation used, which is approx. 1" thick (if directions were
followed.

reprint on the slate structure:
from F.Ghadially
Basically make a light (1"x1") frame smaller than the back of your tank.
Lay it flat over some newspapers on top of a sheet of plywood. Fill
about 3/4 full of a sand-mix (or concrete using small gravel stones).
Author suggests adding a wire mesh for strength about 1/4" above the
newspaper (so it is about 1/2 below the surface of the concrete mix).
Then start stacking pieces of slate, so that you get varying heights.
Author suggest not going more than 1-1/4 to 2" above the frame. Author
used slate pieces which were 1/2 to 3 thick, 2 to 12" in length, all set
on edge into the concrete mix. When finished cover with wet cloths and
plastic (to keep damp for 4-5 days). Wooden frame & newspaper are removed
(he says it can be oiled in advance to make this easier). He then goes
on about soaking the structure to remove it's leaching effect (a couple
of weeks (no fish!) of water changes or can be accelerated by using
diluted hydrochloric or acetic acids, and then soak in fresh water to
remove the acid). In his tank, he had small plants up this structure.

Dr. Ghadially suggested oiling the frame & newspaper for easy removal
from the cement mix. Myself, I am leery of adding foreign substances
which will make contact with the water, so I would use something else, -
perhaps waxpaper. YMMV I would also add a perimeter silicone bead on
the back to prevent scratching the glass, and fry getting stuck behind.
He does not mention any fastening methods, so I presume the rocks used
were bigger at the bottom so it could stand on it's own. Hope this was
of some help.

reprint on his method of curing the concrete
Dr.Ghadially (Advanced Aquarist Guide) described a method for preparing a
concrete background for aquarium use. I've reprinted the article
verbatim, so
feel free to replace litmus paper by liquid pH tests ;o), and the acids
suggested might not be the most readily available on the market. I also
have no personal experience with the process, but the writer was speaking
from his personal experience.

*quote*
The quickest way to cure concrete rockwork is as follows. Place the
object in a plastic container and cover it with water. Add a little
dilute mineral acid until the water shows an acid reaction (red) with a
strip of litmus paper. Dilute hydrochloric or acetic acid is best for
this purpose (vinegar is too weak to treat economically any but the
smallest pieces). In time the alkali coming out of the rockwork will
neutralize the acid and a blue reaction to the litmus will develop. Add
more acid to maintain the acidic state. When the water stays acidic for
a few (3 or 4) days it means that no more alkali is being released. The
excess acid is now removed by soaking & rinsing in fresh water. The
whole process usually takes about a week to 10 days for large pieces of
rockwork.
*unquote*

hth
NetMax

[Alan Silver]

In article >, NetMax
> writes
>re-posting 3 articles.. keep in mind that permanent structures with
>caves making catching cichlids problematic. These plans don't provide
>much in the way of caves, just a slate background, but it could be
>modified as you require.
<snip>

Excellent. Thanx again. Just to be a real pain, do you know of any web
sites with pictures of these sorts of things ? It would be nice to see
what others are doing.

Thanx again

--
Alan Silver

[NetMax]

"Alan Silver"
> wrote
in message ...
> In article >, NetMax
> > writes
> >re-posting 3 articles.. keep in mind that permanent structures with
> >caves making catching cichlids problematic. These plans don't provide
> >much in the way of caves, just a slate background, but it could be
> >modified as you require.
> <snip>
>
> Excellent. Thanx again. Just to be a real pain, do you know of any web
> sites with pictures of these sorts of things ? It would be nice to see
> what others are doing.
>
> Thanx again
>
> --
> Alan Silver

I've attached my 'showtank' web sites. You can check through these for
ideas, but I don't know if you will find many 'permanent' rock
structures. I've got more showtank sites which specialize in styrofoam
as their building material. I'll include them in case that's of some
interest to you.

http://cichlidinspiration.net3services.com/
http://www.aquariumdesigns.com/aquariums.html
http://www.livingcolor.com/
http://showcase.aquatic-gardeners.org/
http://www.saltvandssiden.dk/birger_kim_rylander.htm (marine, Danish)
http://www.aquariumdesigners.com/gallery/index.php?currDir=./Aquariums

Styrofoam construction
http://cichlidinspiration.net3services.com/show_articles.asp?category='Co
nstructions%20-%20Background'
http://www.malawicichlidhomepage.com/panis/pu_background.html
http://www.malawicichlidhomepage.com/aquainfo/invent1.html
http://www.goddijn.com/aquarium/index.htm
http://www.thekrib.com/TankHardware/janne.html
http://www.african.uklinux.net/phpBB/viewtopic.php?topic=1926&forum=8&153
http://www.csd.net/~cgadd/aqua/art_other_netmax_styro.htm

NetMax

[Alan Silver]

In article >, NetMax
> writes
>I've attached my 'showtank' web sites. You can check through these for
>ideas, but I don't know if you will find many 'permanent' rock
>structures. I've got more showtank sites which specialize in styrofoam
>as their building material. I'll include them in case that's of some
>interest to you.
<snip>

Wowee, you've been busy. Thanx a million for the links. I can't see most
of them now as my connection is playing up (good old BT !!!), but I'll
have a good look through later.

--
Alan Silver

[Alan Silver]

In article >, NetMax
> writes
>I've got more showtank sites which specialize in styrofoam as their
>building material. I'll include them in case that's of some interest
>to you.

Hmm, don't know what they look like in real life, but those styrofoam
ones look very realisitic in the pictures. Maybe I'll try that instead
of real rocks. Much lighter and easier to work with. Didn't fancy
putting that much weight in the tank anyway. This way I can sculpt
"rocks" to the size and shape I want without the weight.

Thanx for that.

--
Alan Silver

[NetMax]

"Alan Silver"
> wrote
in message ...
> In article >, NetMax
> > writes
> >I've got more showtank sites which specialize in styrofoam as their
> >building material. I'll include them in case that's of some interest
> >to you.
>
> Hmm, don't know what they look like in real life, but those styrofoam
> ones look very realisitic in the pictures. Maybe I'll try that instead
> of real rocks. Much lighter and easier to work with. Didn't fancy
> putting that much weight in the tank anyway. This way I can sculpt
> "rocks" to the size and shape I want without the weight.
>
> Thanx for that.
>
> --
> Alan Silver

Like any products, there are a few pitfalls to styrofoam, principally in
it's weight and sealing the surface.

Iirc water weights about 55 lbs/cu.ft, and Styrofoam weights about 1.5
lbs/cu.ft, leaving about 53.5 lbs/cu.ft of buoyancy to overcome. For
every cu.ft. of styrofoam, you need 54 lbs of rocks to hold it down, or
you silicone it to the bottom, or use a combination of rocks, gravel &
silicone. Try to use a single piece of Styrofoam, as securing finished
pieces to each other is problematic. For a source of really big pieces,
look into the expanded Styrofoam used in boat dock construction, and then
just carve away all the excess (leaving lots of joining material to keep
any sections from breaking off).

After factory curing, polystyrene (Styrofoam) is inert. If you do not
seal the surface, then you are left with the natural colour of the
polystyrene (white, blue etc) which will eventually get covered with
plant matter (algaes, ferns etc) and bacteria. Many fish will pick it
apart (going after the plant matter which has rooted there), so expanded
polystyrene will fall apart. Extruded polystyrene will take the abuse
better, but rasping plecs will still cause damage.

Sealing the polystyrene allows you to paint it first (I always use
extruded polystyrene). Use a layer of primer and then paint as desired.
I use latex and keep to natural dark colours which will blend with the
natural materials which will eventually coat it. Add some colours or
lines to imitate sedimentary rock, or use some shading to create
imperfections. The carrier used in most spray paints (pressurized cans)
will melt polystyrene, so is inappropriate.

Your choice of sealers is AFAIK, either Fibreglass or 2 part epoxy.
There does exist an epoxy paint which is used for swimming pools, but
it's sold in large volumes and I've never gotten a manufacturer to
provide proof that it would be inert (safe). It's actually more likely
to have fungicides (to prevent algae) so it would be poisonous to fish &
invertebrates. ymmv

The use of Fibreglass or 2 part epoxy is straightforward. Just follow
their mixing & curing instructions to the letter. I use about 3 layers
of epoxy and I sprinkle sand over the final layer, to blend the final
colour and provide some additional texture. It's really an experiment to
get the shape, colour & texture you want. It's not a complicated DIY
project, but it does require a contained working area which will fill
with polystyrene shavings (which stick by static to everything) and
polystyrene powder (which will make your eyebrows triple in size ;~)

ps, if you cringe from the squeak of Styrofoam rubbing together, I'd
reconsider your plans ;~).
NetMax

[Alan Silver]

In article >, NetMax
> writes
>ps, if you cringe from the squeak of Styrofoam rubbing together, I'd
>reconsider your plans ;~).

;-)

Thanx as always for an informative answer. I showed the Mrs some
pictures (from your links) of tanks with fake rocks made of styrofoam
and she couldn't believe they weren't real !! We are going to look into
this more closely. The main problem is working out what shape to make
it. With rocks, you just pile them up and take them down until you are
happy. Here you get to create the shapes from scratch, which gives loads
of freedom, but makes it difficult to get right.

Still, that's half the fun of DIY eh ?

Thanx again.

--
Alan Silver