# Fiberglass tank



## foxfish (22 Aug 2010)

Hi guys, I thought some one may be interested in a plywood & glassfibre tank I built quite recently.
My friend asked me if i could design & build a tank for his lounge - he wanted to keep blind cave fish but also wanted to keep live plants!
I built the tank ok but must apologise on my friends behalf because he never did plant the tank & it still lives in his shed waiting for the "right moment"  :? 

I have built lots of tanks in this fashion, some very large ones too but in this instance the tank was designed to fit a specific space, so I cut out the 18mm ply to suitable size.

I measured up the tanks location & decided on a  42" x 30" x 20"  tank = 1070mm x 760mm x 510mm.
I was thinking along the lines of a 18" deep water level with some type of above water display, rock formation, tree root? Maybe a shelf just under the water level that will be heavily planted & a cave like appearance below the shelf!
I would make the background, shelf & maybe tree roots out of high density foam, in the foam I would make pockets for plants & LED lights.

Just thoughts at that stage but here is how the basic box was constructed.



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## foxfish (22 Aug 2010)

Next up was apply the fiberglass matting....


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## foxfish (22 Aug 2010)

Then apply the first coat of colour....


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## foxfish (22 Aug 2010)

Blind Cave fish! I gave the issue some though & then got to work with shaping some foam to give the impression or rock coulombs .... I wanted to give the effect of caves & dark areas but with areas where the light could reach the plants....


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## foxfish (22 Aug 2010)

A bit more shaping & then the job of coating the foam with a mix of polyester resin, black pigment & mixed grade sand.




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## foxfish (22 Aug 2010)

Next up - apply a black top coat to the tank & glue in the components, the tank will operate a sump so the overflow was fitted as well.


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## foxfish (22 Aug 2010)

The tank was tried in position but like I say has yet to be operational.....



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## sr20det (22 Aug 2010)

very nice, never knew tanks could be built in this manner.  very nice.


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## foxfish (22 Aug 2010)

Yeah good fun to build too but I find the best aspect revolves around the fact you can DIY holes for pipe work very easily.


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## gollum456 (23 Aug 2010)

very interesting, never seen this before!!! whats making it waterproof? whats the fiberglass for? how did you attach the glass front? tell me, tell me now!!!!


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## foxfish (23 Aug 2010)

Well one picture shows the application of the fiberglass mat being soaked with polyester resin, this give structural strength & then a more viscous covering of polyester gel coat makes the product waterproof & inert.
(Its the same stuff boats are made from & readily available)
The glass is simply stuck in with silicone.
I have made some interesting shapes in the past & tanks up to 2.4mt long using the method.


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## Mr T (25 Aug 2010)

Brilliant idea. You could make tanks of any shape and design with that technique.  Love the roots design work too.  

I don't want to sound alarmist however, but being lucky enough to own a small river boat I know only too well that over time, fibreglass is not fully waterproof. Just type Gelcoat Osmosis into any search engine and you'll see what I mean. (Here's a particularly good write up of what happens http://www.yachtsnet.co.uk/osmosis.htm) I'd imagine that the resulting poly glycol filled blister could be pretty toxic to our aquatic chums if it burst. (I of course may well be wrong on this)

Admitedly, with a well made fibreglass hull this can take years to develop but may be something to consider if intending to keep a tank for a very long time. 

Chris


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## foxfish (25 Aug 2010)

Thanks Chris, fortunately osmosis is rarely encountered on modern boats.
What happens when water manages to find a way through the gelcoat, it can then wick its way into the fiberglass, this causes a dramatic increase in weight, causing the boat all sorts of problems!!
However on a small scale, the system is easy to manage & regulate but if one was paranoid, one could apply epoxy resin as a top coat.
The issue is more of a problem on a outdoor fish pond where water can reach the glass fibre from behind or in an open boat where rain water can travel into the glass fibre from the inside!


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## andy (9 Apr 2013)

We're having our large (100' x 60') pond fibreglassed next week (weather permitting) and they're going to teach me how to do it.

Always fancied making a large 12' x 4 x 4' ply and fibreglass tank for the conservatory and using two sheets of acrylic for the front seperated by a bar halfway along.

Marine Batfish and other predetors, A large Arowana or a native coldwater tank would be my choices.


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## foxfish (9 Apr 2013)

Big pond - small lake! please show some pictures.
You would need some thick acrylic for a tank that size probably 28 or 32mm but it would be a great choice for a cold water marine tank (my favourite).
You could insulate the tank with Double R & with the thick acrylic you should be able to run a relatively small 1hp cooler.
I built a similar tank for a sporting celebrity once!!


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## andy (10 Apr 2013)

foxfish said:


> Big pond - small lake! please show some pictures.
> !!


 
I have a facebook page which has covered the pond revamp with lots of photos

Preston Rock garden - Brighton, United Kingdom - Community | Facebook


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