DIY polystyrene

@Zuraki . Okay thanks I think ive got it now. Going to look at builders for durapond, a paint store for polystyrene and mica hardware for silicone because the lfs wants to charge R69ea. Going to check those places today and hopefully start my build this weekend when I have some time

 

This looks like a very good thread, would be nice to see visuals of your step by step process please

 

thats the idea once i get started on the whole thing. just been planning it carefully

 

@Zuraki. im scard after finishing that the polystyrene still floats or doesnt stand up straight on its own....

also how much durapond did you use? 1litre? its very expensive stuff! how many coats did you paint?

heres a start up cost that i went and got today:

mica hardware was the only place i could find everything.

polystyrene 120cm L x 60cm H x 2cm W. i think im going to need 3sheets. @ R56.50 per sheet.
durapond 1litre @ R280
silicone @ R46 per 280ml tube. (starting with one to stick sheets together, going to need much much more)

total startup cost R541.50....

 

so the plan is to cut the poly styrene into x4 30cm pieces. leaving them 60cm high. x3sheets siliconed together @ 2cm each

i have decided on 3 pillars because i think this will be easier than four pillars @21.42cm also i think it will look nicer.

2pillars will be 6cm.

for the 3rd pillar i want to cut out space for my heater and filter intake, to hide them inside the pilar. i will have a spare pillar @6cm thick. should i stick them together making the third 12cm thick? how do i go about making nice holes for water to pass in for the intake? also how to durapond these holes? will a 300w heater melt the poly covered in durapond? the tank is set to 27degrees

 

that is really cool. I will be doing this in December

 

*bump still need replies to my last two messages before i can progress this project.

also how much weight will be needed to keep each pillar down?

 

Hi @nodac , glad to see you are progressing so well. Unfortunately that is the going price for Durapond, if i remember correctly. I used the 1L tub and did both my backgrounds with it. A single coat was enough but I did apply it quite thick. The last thing you want is for the rocks that you stuck to the durapond coating using the marine silicone to tear off at the polystyrene durapond interface. I had pretty big rocks stuck on mine and it is still holding fast.

About the cost ... the durapond, polystyrene and silicone will be your biggest expense. If you work with small pebbles on your pillars I am sure you can get away with much less silicone. I used larger rocks and therefore required more silicone.

My reason for using the Durapond was that the white polystyrene background would have definitely put me off. Aside from that, I have read many other people using polystyrene without a sealant with no ill effects to their fish. So if you can find a more inexpensive way to hide the white polystyrene (maybe even stick enough pebbles over one another) you may very well get away without using Durapond. My big worry with this is that I dont think that silicone will bond that well to a plain polystyrene surface. You can experiment with this by sticking some rocks to the silicone alone and see if it holds under water for more than a month or so.

Another problem I had was that I wanted to leave no black background between the rocks that I stuck to my background to make it look more natural. The problem with this is that you will eventually find yourself sticking 2 mm to 3 mm pebbles into holes between your 5 cm and 10 cm rocks. This takes FOREVER trust me. Allow yourself more time than a single weekend.

Regarding the buoyancy issue of the pillars. My suggestion would be to glue your pillars the way you want them and let them dry. Then, find three or more large rocks of various sizes with which you can experiment. You will also need a tub or bucket with a depth at least as deep as your tank. Temporarily fasten a rock to each of your pillars (using cable ties or something similar) and drop them into your bucket filled with water more than 60 cm deep. If it sinks your good, if it drifts, try a larger rock. once you have found that magic rock size that keeps each pillar down, you can proceed to hollow out a bottom part of the pillar to permanently wedge or glue the rock in place - removing some of the polystyrene in the process. This will further ensure that the pillar definitely stays down.

The holes for the intake you can simply gouge it out with a knife and cover it with Durapond. The Durapond will dry out and you can stick some small pebbles bythe opening using a thin layer of silicone - that really shouldnt be a problem.

The 300W heater is another story. Personally I would not risk bringing a heat source that close to the polystyrene. While i know that the fumes from burning polystyrene is toxic, i really dont know what will happen if the polystyrene is exposed to hot water for long periods of time (the hot water in the first 5 mm adjacent the heater before it gets carried away by convection). I would be very careful. If you can ensure at least 5 cm of empty water space between the glass heater and the polystyrene surface I would try it otherwise its a no from me. HTH and please post pics as it comes along!

 

the durapond is the only way for me to go as well because i dont want to see any white polystyrene, also i want the polystyrene to last for many years. i read that durapond isnt safe in chlorine so that means i cant check if it sinks in the pool??
my tank is going to have my frontosa in it before i get this build done. this build is going to take awhile because i want to do it right. i think i will need to use decent sized rocks and then just fill in the gaps like you did. i keep looking at your build @Zuraki and hoping i achieve something as good as you got.

 

"The 300W heater is another story. Personally I would not risk bringing a heat source that close to the polystyrene. While i know that the fumes from burning polystyrene is toxic, i really dont know what will happen if the polystyrene is exposed to hot water for long periods of time (the hot water in the first 5 mm adjacent the heater before it gets carried away by convection). I would be very careful. If you can ensure at least 5 cm of empty water space between the glass heater and the polystyrene surface I would try it otherwise its a no from me."

i really want to hide the heater from view. maybe what i will do is i will make alot of holes on the sides with a drill and infront so water can easily pass through the poly. and give the back of the poly a few extra cotes of durapond paint so that its protected well. i will make it 12cm thick and cut out roughly 8cm for the heater and intake pipe to sit in. giving me 4cm thickness still for rock work etc to be attached and the other pillars will all be 6cm thick... i just hope it works.

 

i think im going to go look at a garden centre this weekend for some stones i can buy because i want all the pillars to have the same colour stones or it will look funny to me. im thinking about 10cm stones for the main parts and then i will get smaller stones once ive almost finished to just fill in all the gaps. will also need three large stones like 2kg or so for the base of the poly to keep it down. i hope it stands freely and does not need to be siliconed against the back of my tank

 

@Zuraki after looking at your post again i see you only used one sheet of 1cm polystyrene. will it work for me to only use x1 sheet of 2cm poly for the two pillars? instead of making them 6cm thick which is quite abit.

do you guys think i should give up on doing 3 pillars with the 3rd covering the heater and intake? and just do two pillars 60cm wide by 60m high and just have them in the middle of the tank??

 

@nodac , thanks for the compliment. I agree fully with the one type of stone/rock. I tried my best to stick to one type but couldn't get the same type on a large scale. The best thing about this DIY project is that there is no wrong way to do it, as long as it keeps your fish safe. I just decided to do my own thing and it worked out great. You seem more than willing and serious to see this project through. I am sure that your background will be different but also just as interesting.

 

How do you intend to do your pillars? are you going to have them straight and upright or are you going to make them bend at different angles? When you glue the rocks you can manipulate the edges of the pillars by sticking protruding or odd shaped stones. The rock work really breaks the rigid lines of the polystyrene nicely. If you look at my thread you will see in the very first picture that I simply cut a portion of the polystyrene at an angle. One very important thing is to choose the rock colour and texture carefully - you are relying completely on the appearance of the rocks to make it look natural.

 

@Zuraki I was planning on making them straight, odd shapes will affect the balance of my pillars as they will be free standing against the back of the tank with heavier rocks at the bottom to weigh it down. I will use rocks over the edges to make them look more natural. Im going to upload two pictures of drawings for rough planning. Do you think 2cm poly thickness is too thin?

 

Decided im going to make them 4cm thick atleast. Im liking the second idea more because im worried about the heater melting the poly and heat not being spread around enough. Also I like to see the heater going on....enjoy. if I can get this nicely planned I might start this weekend. Im going to look for stones tomorrow morning at stodels.

 

Hi @nodac , I like both your designs - looks very nice. Either of those options will work but I think you should not go for any thickness less than 4 cm. From my experience, the amount of rocks I added tended to bend the whole background structure forward a bit. I had to use a makeshift brace (you can see in one of my pics) when I stuck my backgrounds to the back of my tank. But since you are not going to stick yours in, you will have to consider how you are going to prevent your pillars from toppling forward. I have drawn up a sketch with some suggestions and things to take into consideration. Good luck with selecting your rocks! Let us know what you found.

 

@Zuraki wow thanks for that very indepth and accurate drawing. i dont have a pc so you've kicked my asss on drawings.

you hit my planning spot on. larger rocks at the bottom of the design to act as a anchor and provide balance with the smaller rocks on the upper parts.

the top bracket is a very good idea but i have a full cabinet with an anilimium hood so i wont be able to add the top bracket because my hood wont close. but you have given me a good idea to add in as a backup. i will make two holes at the top which i could tie gut or something in and maybe have a counter weight on the outside of the tank if it does decide to lean forward.

i also think i will go for the x2 50cmx60cm pillars because it will be easier to do and easier to weigh down, also the one covering the heater will need to be atleast 12cm thick and might still melt

some pictures to follow now of the stones that i think i will use because theyre the easiest to buy.... (too many pages to little pictures, making the TASA people angry)

 

Larger stones

 

@nodac - Hey Nodac. Im going to be back on this forum for a while so if you need advice on your DIY background. Feel free to tag me in on any questions you need help with.