Making A Cement Decoration

[Katty]

http/mold-making.com/imitation_sandstone.htm
I found this guide for imitation sandstone, which looks like it might be the method I want to use since I want it to look like natural stone rather than a piece of plastic.

 

[dayzofspeed]

with the resin you will get a much more professional finish, it will have finer detail (if you put it into the original model first of course). dont use builders sand with this, dont forget that tutorial isnt aimed at aquarium keepers, use a sand that you would feel safe putting into your tank as a substrate. i'm glad to have been of some help, you might be on the verge of a whole new business venture here if things turn out well. good luck and hope your decoration turns out well. i might even make one for myself now

 

[GrayScale]

Personally I think making the mould would be your best bet. You could even find a column or something similar to what you want and make impressions in 2 halves in clay. Then once you have the base impression down, you could use a small toothpick/floss thing carve out more detail to your liking. Make sure there is a hole in the top of your mould, clamp the two peieces together tightly to make sure nothing spills out, pour the resin in and let it set. Split your mould back apart and voilà. You might even be able to coat the inside of the mould with a nonstick spray and the spread some sand over it but not press it into the clay so when the resin dry, the sand sticks to the outside of it. I'm sure you could find some aquarium safe sealant as well if you wanted to paint it and seal it. Let us know how it goes!

I suppose you can research how blacksmiths make 3-dimensional cast house decorations. Same principal but different materials.

 

[Katty]

Yes, I wasn't planning on using builders sand if I went with the sandstone resin tutorial. Our LFS actually has sand by the pound for pretty cheap so I would have just bought a pound of that, since it's meant for fish and I wouldn't have 49 extra pounds of sand left over

Grayscale, I'm not sure I understand you. What I saw from tutorials is you have your "prototype", which is how the object would look but made out of like clay or something, then you pour silicone around that and end up with a negative space silicone mold, then pour the resin into the mold. I didn't see anything about making the negative space mold out of modeling clay though. I like your idea since I do have some roman columns that would make things easier if I could copy the stone detail in them but I'm not too sure how that would work.

 

[GrayScale]

Grayscale, I'm not sure I understand you. What I saw from tutorials is you have your "prototype", which is how the object would look but made out of like clay or something, then you pour silicone around that and end up with a negative space silicone mold, then pour the resin into the mold. I didn't see anything about making the negative space mold out of modeling clay though. I like your idea since I do have some roman columns that would make things easier if I could copy the stone detail in them but I'm not too sure how that would work.

That would work as well with making the negative that way as well. I was thinking of using the clay to develop your negative. Sorry I wasn't being very clear I was at work using my Ipod to post and it's not the easier thing to do haha.

Anyways, what you could do is make the negative out of the clay from the start. Start with a big square block of clay and cut it directly in half. Next take your column that you want it to look like and press it half way in one half of the clay and then the other half of the column press it directly into the second half of clay. That way you have 2 halves that if you put the clay together it would form a whole column on the inside. While the clay is still moist you could carve out extra details around the edges etc. Then put then halves of clay together and put a pencil sized hole directly down the middle of the top of the two pieces of clay into the hollowed negative column. Separate the two pieces and let the clay set and harden. When it's set, combine them back together securly maybe using some clamps. Use a funnel to to pour the resin into the hole you created on the top. Let it sit for awhile for the resin to harden. Once the resin is hardened. Release the clamps and pull apart the clay. Bingo presto, your resin column.

If theres a part you dont particularly understand just let me know. I'm not very good with explaining and if the tutorial seems easier then i would go with that.

 

[Katty]

You can use modeling clay instead of silicone to pour resin into? I think thats the part that confused me most.

 

[the biffster]

i am sure there was some one on the
salty side making rock caves and stuff
like that out of cement or concrete
or something but i cant find it been
looking for but no joy

 

[Katty]

Today I got some sculpey clay (its clay that hardens when baked) to make the prototype out of. I found I can use one of my old roman temple fishtank decorations to "stamp" in a stone pattern onto the clay, it works pretty well. Once I carve out the design I will stamp the whole thing to make it more stonelike.

This is it so far. I will probably be working on it for at least a week to make sure I have it perfect.

 

[BigC]

From a saltwater enthusiast (making rock formations from cement) you can make some exciting structures using "Snowcrete" (a white cement compound available from builders yards) This level of thinking can easily be transposed to the freshwater side so long as the end result is left to cure and is sealed properly. A box of sand can be used as a mould and impressions can be made in the sand (ie tree roots etc) and the Snowcrete mix poured into this. Once set your structure is easily removed ready for the next stage. There are many YouTube videos surrounding the making of Liverock for the marine environment which as I say can be modified (mixes and additives) to suit any freshwater aquaria.
I hope this helps
Regards
C

 

[BIG BAD BARRY]

There are some great examples of backgrounds made by people.
The better detail when using polystyrene/styrofoam is when they use extruded polystyrene foam XPS - IMO!
http/en.wikipedia.org/wiki/Polystyrene
This article explains things nicely. People need to bear in mind the environmental impact of such stuff when disposing bits ofit as it has caused harm in the marine environment.
As i understand it, this method requires the background to be fixec with silicon to the tank.

Cost is always a factor!

This company make resin backgrounds that dont need to be fixed and filter and other components can be placed behind the backgrounds.
I will certainly consider them for the future as the cost is not that much more than suppliers of foam background and the quality looks fantastic. Also, it is independent of the tank so can be seperated easily when required from the tank.
http/www.aqua-maniac.com/content/4-about-us


Resin products appear to be quite expensive.
This is a company that sells them and has a useful section on instructions and guides.
http/www.resin-supplies.co.uk/resins.htm

I like doing things myself but the biggest cost at the moment appears to be sealing polystyrene/cement backgrounds to prevent them leaching water changing compounds into the aquarium and protecting them from wear. The Sika product appears to be really expensive for this purpose.

 

[JasonandJill]

I wouldn't put (building) cement anywhere near a fish tank. You could do a water change with hydrochloric acid and not do much more damage. Even getting it on your own hands can cause severe burns if not cleaned off pretty quickly.

 

[Katty]

Thanks for the info, but I've already decided against concrete right now. A friend who works with concrete warned me about the alkaline burns you can get with that stuff.

Currently I've decided on going with making an RTV silicone mold and filling that with aquarium sand mixed with resin. The resin and silicone is expensive but perhaps I can buy a smaller package of resin (8oz for $12 USD) since most of the mold will be filled out with sand anyways, the resin just "filling the gaps" between the sand. I'm not sure if I should update with my progress here or not, whether anyone would like to see it. Or if I want to show my progress if I should make a new thread since so far I have the logistics figured out of what I want to do, all I have left is to get the materials and do it.

 

[Aqua Tom]

I wouldn't put (building) cement anywhere near a fish tank. You could do a water change with hydrochloric acid and not do much more damage. Even getting it on your own hands can cause severe burns if not cleaned off pretty quickly.

We have had the safety talk about a guy working on site & got concrete mix in his wellys, didnt think anything of it & acrried on working all day.. It burnt his ankles so badly he lost a foot.


I am constantly getting this stuff on me but it is washed off as soon as I can do it.

 

[dayzofspeed]

i've seen that video, but its a bit extreme as i dont think anyone is going to make an aquarium decoration with a welly full of cement. and anyway aquarium decor made with cement is not solid cement its a couple of very thin layers "painted" over a polystyrene form that are then sealed to prevent leeching. ive worked with cement for years and never had the slightest problem even with bare hands, thats not to say i would put my hands in a tub of wet cement for a couple of hours

 

[OldMan47]

Concrete is made using lime among a few other ingredients. It is really not suitable for anything that does not readily tolerate very high pH levels. With that said, I have made ponds out of concrete when I was younger and painted the resulting concrete casting with waterproof paints. When I was done, I added fish and had no real trouble with them. I can only assume the waterproof paints somehow sealed the concrete well enough to prevent water quality problems.