Hi it’s Lee from the Japanese water gardens.

This is part 4 of my series of short videos detailing the construction of a new quarantine system at the Japanese water gardens. 

In previous videos we installed bottom drains, built a ply lined timber frame  and cast dish
shaped concrete basses. 

In just a few short weeks we are planning to stock the tanks with fish in time for the new season so with lots to get done we have been busy working on the system.

We had made arrangements for Stuart from NKB to fibreglass the system for us. He had to make some changes to his busy schedule in order to fit us in. So it was imperative that everything was ready for him.

I made a list of jobs that needed to be done and got started ticking them off.

First off the list was filling the screw holes and joints between the plywood. I just dipped my finger straight into the filler and rubbed it into holes. 

The gaps between the plywood in the corners were not large because we had cut a 45 angle on them.  So all that was needed was to smear filler up and down the edge. 

I wasn’t looking for perfection but its how amazing how even small imperfections will show through the fibreglass. 

The open tops in the corners needed boxing in. I could have cut plywood triangles and screwed them in but I had a idea that would save some time. 

To fill the void behind the corner pieces I rammed them full of loft insulation. 


It wasn’t really that we wanted to insulate it. It was just a very easy way of filling the void. 


And I had plenty of spare insulation. 




Then I mixed up some sand and cement and filled the last few inches. 


I pressed it down firmly and smoothed it over.




To take off any high points on the plywood I planned down the tops of the tanks. This also removed a lot of the roughness on the saw timber frame. 


To further improve the finish around the tops I ran my router round and put a small bevel on the top of the plywood. 


Running down the back of the system we installed a series plywood panels. These will serve as a splash back and bridge any gaps between the wall and system.


Should a fish jump up it cann’t get stuck floundering in a corner or get traped down the back of the system. 


It would just roll back into the tanks. 


Then I started to rub down everything. It made sense to start high up and sand and brush the muck and dust down into the bottoms. 




I used an orbital sander to smooth over plywood. The screw holes were barley noticeable. 


 
I then brushed out the bases to clear away any loose debris or sand from the render. 


And finally the insides of the bottom drains were roughed up with sand paper to make sure the fibreglass would key to them properly.


Everything was ready in the nick of time. 


Stuart was coming the next day to start 


Fibreglass is the best method of waterproofing a structure such as this. 


It is far stronger and more durable than paint.


You don’t get any folds or creases that would be unavoidable if you used pond liners. 


Fibreglass can be applied to a wide variety of surfaces and will provide a waterproof layer that adds a significant amount of structural integrity.  


Although I have dabbled with fibreglass myself. With a job such as it’s best to bring in a professional installer. 


Polyester resin is mixed with a catalyst. 


The resin is spread thickly onto the surface and a sheet of chop strand glass matting is pressed onto it. 


More resin is rolled on it until the matting is completely wet out.


A paddle roller is then used to press everything flat and work the matting into the resin. 


Sometimes several thickness of matting will be used each wet out with more resin. 


The resin sets solid quite quickly depending on the conditions and amount of catalyst added.


So preparation and experience are required in doing a good job. 


A final layer of resin is applied over the top to form the watertight coating. This can have a pigment incorporated and will contain a wax that is needed to fully cure the resin.  


This is referred to as the flow coat.


Once all of the flowcoat has been applied it it left for several days to fully cure. 


The tools are cleaned and sometimes stored in acetone. A solvent used as the active ingredient in nail polish remover.


In the next video we will be tackling the pipe work and an unusual filtration system so be sure to subscribe if you have not already done so. 


Please thumbs up the video, feel free to comment or ask any questions. 


It’s bye for now from Lee at the Japanese water gardens.