DIY polystyrene

Smaller stones

 

@ryanj252 thanks man but i think Zuraki and i have got most of it down, my only issue right now is finding nice stones and deciding on how thick to make the polystyrene. 4cm or 6cm, 2sheets or 3 sheets. if you can help with that, that would be great.

im looking for stones that will look most natural, what i posted earlier is all stodels had and im not sure if that will work because they all look very smooth....

 

@ryanj252 also i need to find a hot knife i can lend for a day just to cut the poly styrene nicely. or what else is best to cut it with to achieve the least breakage?

 

What are the stones for?

Regarding thickness I suppose its entirely dependent on your design. I had cut off sheets from a fridge packaging that I cut into pieces that made up my design. Some where cut offs that I glued on with sealer and toothpicks to stabilize and strengthen. Other sections I cut out with a knife that was over a candle or used a cheap soldering iron to carve in extra detail like cracks or caves. Dont go into too much detail is that all gets covered up by cement later on.

My opinion is too obviously add as much depth as you can. The flatter you background, the more pointless, as you coulda just used a picture. But source your inspiration from actual underwater photography of lakes and rivers.

Have a look at this background I built for my uncles tank.

http://www.tropicalaquarium.co.za/showthread.php?8975-1-3M-DIY-Background-Tank-Brand-New

 

@ryanj252 look @Zuraki profile for the first tang build. im not going the cement route i dont like it.

im going to silicone the stones onto my poly to weigh it down. im going to have x2 20cm pieces that i will cut up and use to add some depth to the design. im just worried the 4cm will break when trying to put it in the tank once its complete... do you think 4cm will be enough?

 

That is an awesome idea. Nice and original aswell. My only worry would be the rocks affecting pH. But i dont know

What about siliconing your poly into the tank and then working from there? 4 sounds good enough.

 

@ryanj252 i dont want it to be siliconed to my tank and work from there because my tank has water and fish into it thats why it has to be free standing and be able to be moved into the tank freely. please read the diy from the start.

@Zuraki if all goes well this weekend i should be able to start off with siliconing all the poly together and maybe even first coating of the durapond black :nuts: i probably wouldnt have been so serious about it if it wasnt for you and tasa, i cant dissapoint now. my final project i think will look similar to yours just on a bigger scale

 

Just read through the whole thread now, I have a better understanding! (Sorry about that)

All in all, i see no problem with you design and idea. As you probably noticed, the only problem might be buoyancy VS thickness of polystyrene.
BUT!! - I have an idea though, it might add some stability. What about buying a set of 8 neodymium magnets in the following order and place:



Im not sure what effect the metal would have on the water chemistry, but you could engrave holes in the back of your poly, pop some silicone and the add the magnet and then cover with silicone again.
Theoretically your background should actually just "float" in place and you could slide them in and out whenever you need to do maintenance.
Leme know what you think. Im actually surprised i thought of such an awesome idea. Hope it works though..

 

@ryanj252 that is a pretty good idea! then i dont need to use big rocks at the bottom to keep the polystyrene up against the back!

i did a quick google on that type of magnet. fish safe but now questions and worries...

1) will 8magnets on each piece 50cmx60cm be enough? (4inside, 4outside)
2) will the magnets be strong enough to hold between 10mm glass/
3) if the magnets connect hard will it crack my glass??
4) Where can i find these magnets and at what cost?

need to decide on final design before i end up doing the durapond layers because i would need to fit the holes for the magnets beforehand and silicone them in after doing the durapond.

@Zuraki ideas on ryanj252 's plan?

 

1) Neodymium magnets are very strong. I suggest you just take your piece of poly and add the magnets and do a float/strength test just like that. Keep adding magnets until it sits in place. Then you're assured that it will only get better when you add the stones weight into the equation.

2) The magnets are super strong, 10mm shouldnt be a problem.

3) I might fear the cracking aswell. But sealing the magnet should cushion this:



4) Check BidBoy
http://www.bidorbuy.co.za/item/109875218/Neodymium_Rare_Earth_Magnets_Round_18mm_x_3mm_Each.html

 

Or just put a small piece of rubber and/or leather between the magnet and the glass (both sides), should help.

 

i cant really do a full scale test beforehand... @ryanj252

as the tank will have water in it. i will need to durapond and seal everything before it goes in.

is there somewhere else in cape town i can get the magnets?

i just phoned mica hardware and builders wharehouse they dont have or know where i can get neodymium magnets only normal ones

 

Order them dude...shouldnt be that much of a wait. Check Magnetec.co.za

And you can do the test with water in it. Polystyrene on its own wont harm your water.

 

@ryanj252 I need to get the magnets somewhere locally tomorrow so I can start my build this weekend

 

Hey! Sorry for the long delay - got caught up in work. I really like @ryanj252 's idea with the magnets. You don't permanently mess up your tank and you can remove the background to clean behind it. Very nice. @nodac , you seem to have things under control. Those rocks look good. The small ones shouldn't be a problem even if they are a little smooth. Maybe take a few rocks glue it with silicone and wait till Saturday night/ Sunday morning for it to dry and then see how well it bonded - you can do this while you glue your polystyrene sheets together and wait for them to dry. About the drawing - I just use my pc because I am like a five year old with crayons when I try to hand draw hahaha. In the end the simplest of sketches that gets the idea across is the best. This is turning out to be a very good diy thread - anyone with suggestions should add their 2c

 

Hey @nodac - just some more info - I only used the Durapond on the front and sides of my backgrounds. The back remained uncoated. If you don't need to use big rocks then you can add just enough small rocks to almost make the backgrounds perfectly buoyant. In other words the weight of the rocks perfectly offsets the polystyrene's tendency to rise. IF you can manage that, you will probably get away with only 4 magnets for each pillar. It should be very easy to make a circular hole in the back - I used a PVC pipe to bore out some of those round holes in my background and it worked like a charm. I didn't worry about cutting the polystyrene perfectly because the durapond is rubbery and after applying it, the jagged edges are smoothed out a lot. Besides you are going to cover it with rocks anyway. I used a normal steak knife to cut mine. The beauty is that it is really up to you how you want to connect it and you have a lot of options available

 

@Zuraki the magnet idea is fantastic! I am going to try use it. I just need to see tomorrow what the best magnets are that I can get close by. The background will be flush against the back and shouldnt need to be removed for cleaning.

Why was the back uncoated? I was under the impression it all needed to be covered so it can last forever?

Good idea for making the holes! Im going to go with 8 magnets per pillar just to be safe incase I dont get the neodymium magnets.

Tomorrow onwards pics will be more abundant. This is an entire tank setup for frontosa. My plan tomorrow is to get the poly. Silicone and magnets. I will silicone together my two 120cmx60cm hx2cm thick and cut out the two pillars. I will take lots of pictures dont worry!

 

Cant wait for the pics. My argument with my background was that I used enough silicone on the back to almost entirely seal off the polystyrene, but only time will tell.

 

@nodac!! GO GO GO GO!!!
http://www.allmag.co.za/products/magnets/permanentmagnets/rare-earth-magnets-neodymium.html

ALL MAG


Info@allmag.co.za


55 Rohm Rd
Goodwood
Cape Town

 

Genius idea Ryan, I'm just a bit worried that the silicone might tear loose with the magnet, so I thought you could also attach the magnet with a cable tie tied around the magnet and another one through the styrofoam looping through the first cable tie, or just fishing gut tied to a button on the other side of the foam. The button could also be sunk slightly deeper to hide it.

My idea is waay more hassle, but if the silicone doesn't hold then maybe it could help.