batmanforever Posted July 1, 2007 Report Share Posted July 1, 2007 Hi everyone, I would like to make a "rocky cave back ground" from a 150mm thick polystrene slab I have. I figure if I cut it so it fits into the inside back wall measurements of the tank so it wedges itself between the bottom of the tank and the top brace it will stay there. I will have to cut it vertically into "3" so I can get it into the tank. The vertical cuts will be crooked as to conform to the cave cut outs etc. I can shape the rock face using an angle grinder with a coarse sand paper disc , the caves can be dug out using a die grinder with a knurled ball bit and then by spraying solvent over this will give a smoother texture. Holdfast put out coloured pond sealers that can be painted on to give a black/grey mottled effect. I would appreciate any advice, links etc batman :bounce: Quote Link to comment Share on other sites More sharing options...
fishy_t Posted July 1, 2007 Report Share Posted July 1, 2007 Hey badman I pm'd you what I did with concrete but your plan sounds pretty good! One thing I would defiantly do is a sample piece, just so you can so what effect you will end up with - solvent might end up with a very uniform pitted look as each polystyrene ball collapses - so you'll need to make sure however you treat it makes it look good - you could just try a heat gun cause I know that works pretty well Quote Link to comment Share on other sites More sharing options...
ryanjury Posted July 1, 2007 Report Share Posted July 1, 2007 Sounds like you have a pretty sound plan I would like to try and make one of these backgrounds at some stage they do sound interesting.. do people cover them in concrete sometimes? Quote Link to comment Share on other sites More sharing options...
WEKA Posted July 1, 2007 Report Share Posted July 1, 2007 I made mine from two layers of 100mm polystyrene. Cut to fit 15oomm x 600mm tank. Held them together with kebab sticks while I cut out the caves and face with hot wire cutter. Made it easy to make swim thru and caves by splitting the sheets. Several layers of runny concrete material over the front and into the caves. When this had cured I cut out all the surplus poly from the back and then concreted the back as well. No buoyancy problems. Quote Link to comment Share on other sites More sharing options...
ryanjury Posted July 1, 2007 Report Share Posted July 1, 2007 has anyone got any pics of the backgrounds they have made? Quote Link to comment Share on other sites More sharing options...
WEKA Posted July 2, 2007 Report Share Posted July 2, 2007 Hi Ryanjury These are pics of my poly background I described above. I added a couple of "squids" to give a bit of water movement. My anti syphon vents into the cavity behind the wall and flows thru meshed holes in the back of each of the caves. The whole wall has a silicon "gasket" sealing it to the the tank with an overflow for the outlet to the sump. Quote Link to comment Share on other sites More sharing options...
Navarre Posted July 3, 2007 Report Share Posted July 3, 2007 Nice job guys. Remember that if you use solvent or heat to "smooth" the surface then you can change the outside shape of the poly. This means it might not fit if you pre cut to exact size so be careful there. If you "paint" the poly you can sprinkle with diffent colour and textured sand in differing amounts to give the background shape and shade etc. Also I have never sealed the back of mine as poly can be poreus(sp?) depending on bead size and this can provide over time a considerable filtration advantage. Also some people use several layers of sand/cement to fix the front surface so grazing fish can not dislodge any poly. And it can be adviseable to soak the finished item with several water changes to remove any loose finish and also decrease chemiacl leachates. HTH Navarre Quote Link to comment Share on other sites More sharing options...
fishy_t Posted July 3, 2007 Report Share Posted July 3, 2007 looks awesome weka! Good job! Quote Link to comment Share on other sites More sharing options...
livingart Posted July 3, 2007 Report Share Posted July 3, 2007 nice job, good photos good descriptions well done Quote Link to comment Share on other sites More sharing options...
Rockerpeller Posted July 3, 2007 Report Share Posted July 3, 2007 damn thats an awesome background WEKA. Great use of the SCWDs as well. Quote Link to comment Share on other sites More sharing options...
davidb Posted July 3, 2007 Report Share Posted July 3, 2007 sweet Job Weka Quote Link to comment Share on other sites More sharing options...
fishy_t Posted July 3, 2007 Report Share Posted July 3, 2007 Here are some pics of mine - te first two were a shile ago as you can see from the size of my fronts! My tank is an L shape which is why, even though I was going to do a background like weka's I ended up making two 'piles' of rock, same way as weka I guess but I plastered on pretty thick concrete... As you can see from the 2nd and 3rd picks, the algae makes it look nice and natural after abit Quote Link to comment Share on other sites More sharing options...
batmanforever Posted July 3, 2007 Author Report Share Posted July 3, 2007 WEKA and fishy_t awesome job. Well done!!! Hard to match. I wonder if anyone else has something similar? Quote Link to comment Share on other sites More sharing options...
WEKA Posted July 3, 2007 Report Share Posted July 3, 2007 Thanks for all the nice comments. The tank is designed to be a cold marine but unfortunately it has been a long term project and has not seen any saltwater as yet. In the process of putting in a new kitchen and shower room at the moment amongst other things but will get it up and running for next summer. Still trying to get rid of some symptoms from a serious case of the bends on 31 March so not allowed back in the water(for a while) anyway to catch crays etc for the tank. Quote Link to comment Share on other sites More sharing options...
ryanjury Posted July 3, 2007 Report Share Posted July 3, 2007 Awesome pics guys I think I may have to give this a go sometime.. Do most people use concrete over it to get a rocky looking finish? Quote Link to comment Share on other sites More sharing options...
Blackadder Posted July 4, 2007 Report Share Posted July 4, 2007 I did my background with concrete over the top to give it a rocky finish and to stop it floating. Needs quite a bit of concrete to stop the polystyrene floating though. Quote Link to comment Share on other sites More sharing options...
fishandchips Posted July 4, 2007 Report Share Posted July 4, 2007 Man they all look awesome. Has given me many ideas. Does the concrete leach at all in the water? Quote Link to comment Share on other sites More sharing options...
fishy_t Posted July 4, 2007 Report Share Posted July 4, 2007 yeah - I had to hollow out tonnes of mine and pour in concrete to get it to sink! Quote Link to comment Share on other sites More sharing options...
fishy_t Posted July 4, 2007 Report Share Posted July 4, 2007 it keeps the pH up! but thats all its just like having a HEAP of limestone in your tank! Quote Link to comment Share on other sites More sharing options...
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