New 4Ft with DIY 3D Background

WoW, now im worried, i gotta BIG block of Poly !!!

 

Hi Roger, hes very cool, terrorizing My 2 girls like Mad
call u later Today, must return ur cooler

and thanx once again
will post pics of them as soon as i get a decent Camera

 

@WillemNicolaas What sealant have you used? I made the mistake of applying a solvent based sealer onto the background directly...ate away some poly.

@Luis Add another layer of cement...make the mixture a thicker paste. Maybe add a little sand to the mix (also gives the benefit of a rougher texture).

 

ya, gonna have to do something, thanx Martin

also still looking for the RIGHT 4Ft, with out a Tank thers not much i can do to check Buoyancy rite now ...

 

Test the buoyancy in the bath

 

I've been watching this thread with some interest.

The thread title indicates that it's a BACKGROUND for a fishtank, however I am assuming this is actually for the bottom of the tank, and not the background??

Let me give you some tips that I learnt by watching my poor sister put a piece of poly under her huge rock pile:

* Firstly, Poly is more boyant than what you think. If the single container of waterproofing you are using is not heavy enough to hold it down on it's own, then more and more coats is not going to help either. The weight of the container is the weight of the finished product. It won't get heavier just because it's drying. (Technically it should get lighter, because it's loosing moisture due to evaporation)
* Secondly, I do not believe substrate on it's own will hold this down. You will need a fair amount of rocks.
* Poly is flexible. If any section of the poly is not weighted down, it will tend to lift up. Unfortunately this is what happened to my sister. A piece of poly cut to fit her tank was put in, substrate added, and the pile of rocks was added to the centre. The sides had no weight. The result... the poly on the sides lifted, the substrate slided underneath, and had she and her husband not been quick on the draw, the pile of rocks would have cause a few cracked glass panes.
* I personally do not believe that silicon is a suitable sealant to hold the poly down. Poly breaks too easily, and I fear that with the amount of buoyancy in that piece of poly, it is simply going to delaminate... leaving chucnks of Poly stuck to the base, and a pile of substrate and plants floating at the top.

The next question is actually just an aesthetic question and I ask out of pure interest. I notice a few caves, overhangs etc. Are you planning on covering them in substrate to camouflage them? Or are you leaving them exposed the way they are?


My own suggestion here to make this work (And this can apply even if you are using it as a background)

Using fairly long cable ties, bend them in half, and where the bend occurs, EPOXY the cable ties to the base (or back pane) of the tank. I would put in so many that when you think there is enough, double up. Make sure they are spread out evenly. Then, cut slits in the Poly to match the positions of the cable ties, and slot all the cable ties through these slots. You can cover the base in silicon first, this won't do any harm. Then take precut lengths of something ridged (and waterproof) (eg. conduit) and basically cable tie these tightly in place. Thus this will pull the poly down against the base.

Do a test with one or two cable ties first, because you may find you need to adjust the ratio of how you bend the ties to ensure a tight fit.

 

I agree that poly is extremely buoyant and I wouldn't even try to hold it down with rocks & substrate. You MUST MUST MUST glue it down with silicone. I cannot predict what yours will do exactly, but it is thick. @Zoom I take it you're implying that having the poly at the bottom is worse than on the back? I would agree, but if a bit of silicone can hold a 500L fish tank together, surely it should hold the poly down (if sufficient quantities were applied)?

I'll try get a pic of the back of my background to show how I glued it.

 

I don't doubt that the silicon won't hold it... the silicon will most definiately bond... but the poly may tear away. Meaning it will snap off. The glue won't fail... the poly will.

 

Another possibility would be to cut the poly into smaller chunks & glue down separately. I suspect that it would not delaminate if the silicone were applied broadly enough (5mm wide stripe)...only way would be to test it before hand. I would, however, not use such a thick base to start with. The thinner you can go, the better.

I would heed Zooms advice, since he's experienced the worst. I always try to consider as many possibilities as possible...doesn't mean I'm right In the 'field' of DIY...TEST TEST TEST before implementing anything!

 

Thanx 4 the ideas Guys, the project is currently in 4 pieces and i was thinking of silicone on the base and the bottom of the Tank
also as u mentioned Ashley, i have caves, overhangs and holes in the base and on the main focal point. Those i was thinking of filling with Aquasoil, both to cut down on costs and to weigh the piece down and then on top of that i was gonna do my scape ( including SOME Rocks, but not Tons, lets see )
tomorrow or so im going to give it the final coat of cement with a green oxide Tint and then seal it ( what should i use here Guys? )
after that im going to let it dry for a week or so and then start with the leeching, remenber that im in no hurry as i dont even have the 4Ft Tank yet ...
once i get the tank hopefully all the cement has cured and i can start with the Aquasoil and plants, the scaping and the cycling of the water ...
guess its gonna b a while till this Baby sees Fishies!! but im cool with that, wanna do it proper this time, try and grow some nice plants 4 a change

thanx 4 the Help Guys, pls keep it coming
will post more pics as the work progresses.

 

or should i leave the Base out completly??? stick the Rocks to the floor of the Tank and make Aquasoil pockets some other way??

 

THAT is possibly a VERY good solution.
Maybe @Sean J can give you ideas on creating ADA pockets. I'm not sure how this will work, unless you cap it with a heavy substrate. The ADA is VERY light. (And will not be any use as a weight to hold down the Poly either btw)

 

I will just have to go look at the shop again but will get it and post it for you... Good luck with keeping that puppy down...

 

Aquasoil, when wet is not light. But, use silicone to stick the rocks down. The problem with this, is that if a rock isn't quite positioned correctly, then you can't move them afterwards... Just make sure your substrate is packed in deep enough to hold the rocks firmly, and they wont fall over.

The aquasoil actually makes a great rock holding substrate.

 

How about just using cheap, thin plastic containers to hold the aquasoil. Not anywhere near as buoyant as poly and will be held down by normal substrate yet will separate the aquasoil from your normal substrate? I don't have a pic, but something like the containers you sometimes buy mushrooms in / craft paint trays / similar?

 

Just got the Tank :love: WoW, 4Ft is SOOOOOOOO much bigger then my 3Ft, and heavy ...

 

my background dosent look SOO BIG anymore!!

 

Looking nice man. Gonna look nice with some plans and fishies...:bigsmile:

 

oh YES, but my SO is gonna kill me wen she sees the size of this thing ....

 

Awesome...looking forward to the final product! Good luck with the negotiations