# One way to make a Fake Rock



## Caveman (Jun 26, 2005)

G'day everyone, just thought I'd share an easy way to make realistic fake rock. This technique is just a modification of techniques used to make concrete rocks for landscape gardening. All I've done is take the final finish and apply it to a lightweight polystyrene base. The result is a tuff and very realistic lightweight rock that will easily handle dragons and small monitors. With a few more coats it would probably handle larger monitors too. The downside (like most realistic fake rock) is that it is not a sanitary surface. Like a real rock it is rough, slightly porous and hard to spot clean. I would try to make it so you can remove it occasionally and hose it down. Anyway this is what you need.

Polystyrene
Scavenge around to find polystyrene. Try tips and junk yards, I got more than I'll ever need from a junk pile at a milk factory. It was an old freezer lining but once I removed the tin, stripped the glue and soaked it in bleach overnight it came up as good as new.

Color Hardeners
Color hardeners are a mixture of off-white portland cement, mineral oxide pigments and fine sand (1:1:1). They are used to add color to various cement based products and dry almost as hard as concrete. They are sold in powder form and you can buy the oxide powders separately and make your own by mixing the above ratios. Art and hobby stores sell small amounts of mineral oxide powder and common colors can be found at most hardware stores. A 1kg tub of black, brown or red pigment costs less than $10 and a small bag of portland cement around $5.

Concrete Bonding/Sealing Agent
You need a concrete bonding/sealing agent (acrylic polymer) to bond the color hardeners to the polystyrene as well as each layer of hardeners to the next. This forms a plastic like bond giving flexibility that strengthens and holds everything together. There are many different brands available so look for a cement additive/surface bonder/sealer that dries clear and non-glossy. A similar product that you can readily find is Bondcrete and a 500ml bottle costs less than $10.

Note: This is essentially a concrete rock and these products will not harm your animals but if you want to use your rock as a water feature I would use a product like Pondtite between the base coats and final color.

The polystyrene before I ceaned it up and color hardeners. The dark black powder is straight mineral oxide pigment and the lighter black above has been mixed with sand and cement.






OK, lets start by making a rock formation. In theory you could use any material that's rigid enough to hold it's basic form but polystyrene is easy to shape. Just start breaking the polystyrene away at the edges and shaping it. I use a paint scrapper and a couple of screwdrivers. Don't get too fussy it will break away and look natural on it's own just use your thumbs to round off sharp edges and make the shapes you want. Use the KISS principal because you don't want areas that your animals or insects can get to but you can't. Also watch out for crevices you can't get to with a paintbrush (if you have to get complicated coat hard to reach areas before gluing your layers together). Making a built in wall is pretty easy, just start at the bottom and go for it. Making a 'free standing' rock is a little harder and it's easier to start at the top and work your way down.

The basic polystyrene structure. I use a latex based glue to hold everything together. It dries fast and seems to hold better than fast drying hard glues.





Now just coat a section of your formation in Bondall and Sprinkle color hardener over it (just use a common color for the base coats, I use grey). Now grab a paintbrush and tamp it down so the powder becomes damp and pasty. Continue sprinkling powder and Bondall as needed until you have an even first coat over your entire formation (you don't want to make it too thick, just cover the polystyrene). Leave it overnight to dry and repeat this step (use Bondall and let it dry between layers) until you have the thickness you need.

Here is my rock after two base coats of color hardener. It's now a hard solid structure that would break your knuckles if you punched it.





Now all you need to do is color, texture, highlight and age your rock. The colors you use are totally up to you this is just an example of how to go about coloring your rock. Sprinkle a few colors over your rock so you get good variation and tamp it down with a paintbrush dipped in Bondall so that the rock is mostly one color with some areas darker and some lighter (use a dryer brush to get less mixing of color). Now mix a little dry sand with black, red, brown or whatever colors your using and sprinkle it over the surface while it's still wet, this will bring out the texture. Now leave it to dry overnight then wash off the excess and loose sand. What you are left with is the overall color of your rock and it's almost finished.






To add highlights to your rock mix the color hardeners with water to a thick pastey consistency and with your hands just add highlights of color here and there. Now all we have to do is tone the color down and age the rock. Mix black oxide powder, with water until you have an almost transparent mix (this is known as a tint or dye). Now just flick the transparent mix over the rock work. The idea is to tone the color down and make it look natural.

Adding color highlights. You can't really see it in the pictures but highlights add that extra touch of realness.





The almost finished rock after being tinted with black oxide pigment.





Once the tint has completely dried give it a final coat with bondall to seal in the color and your rock is finished. If you made your tint to dark wash some of it out and let it dry before sealing it.





And thats all there is to it! You now have a very realistic hard wearing rock, that is much lighter than a polyurethane rock of the same size.


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## celticskull (Jun 26, 2005)

*RE: Fake Rock*

thay look great caveman wish i had the time to make some... welldone


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## Jason (Jun 26, 2005)

*RE: Fake Rock*

caveman they look great just wondering were you live and would you be interested in making them and selling, if the price is good i may be interested...if you live in sydney


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## Pyror (Jun 26, 2005)

*RE: Fake Rock*

That is awesome!

I've always wanted to have a go, but not known how to go about it. This topic should go under feature articles, or be made sticky. In any case i'm going to copy it to a word doc. So i can print it off.

Just out of curiosity, how much did it cost to make the rock, start to finish, in your guide?


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## lutzd (Jun 26, 2005)

*Re: RE: Fake Rock*



Pyror said:


> This topic should go under feature articles, or be made sticky.



Your wish is my command! Well, sometimes....! ;-)


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## diamond_python (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

Great stuff. Based on the price of fake rocks these days, it really is a great way of doing things. I used to know a website that also gave step by step instructions on how to make them. If I can find it, I will post the link.


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## Tommo (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

thanks for sharing your idea, ive seen other ideas using polystyrene and makeing fake rocks, but they usually end up looking abit tacky and not very hard. this one looks very good, ill definatley be trying this

can a rock pool be made for these, or would teh chemicals in it be released into the water?


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## stencorp69 (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

That's phenomonal, I can't believe how strong your daughter is  . You've done a brilliant job with the fake rocks - I don't have an artisitic bone in my body though so it wouldn't matter how good the instruction are, mine would still look crap.


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## instar (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

Awesome Thanks mate, have saved it, will give it a bash. Looks great!


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## alexr (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

Thanks Caveman for taking the effort to share this with us. 



Jason said:


> just wondering were you live and would you be interested in making them and selling, if the price is good i may be interested...if you live in sydney



Me too and I said it first...:wink:


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## ashley_morris22 (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

looks great


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## africancichlidau (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

Top job there, thanks for sharing


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## dobermanmick (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

Thanks for taking the time to post that its a great idea !!!


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## BROWNS (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

Nice work Caveman  Have you had a go at making fake rock hides in a siimilar way?


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## junglemad (Jun 26, 2005)

*RE: Re: RE: Fake Rock*

You're a champion Caveman. That finished product looks excellent. I am going to give it a go as a lining for the back wall of my aviary using polystyrene sheets i had for fish tank bases


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## Hickson (Jun 27, 2005)

*RE: Re: RE: Fake Rock*

That looks brilliant Caveman!

In paragraph 3, titled "Concrete bonding/sealing agent" you don't actually name the agent you use, but later you start talking about Bondall, so I'm guessing thats your preference.

I recently read another article on making fake rocks that had an interesting technique - to give the polystyrene a natural 'rock' look (pitted surface), they suggested you use a brush to paint on Turps or paint thinner. This dissolves the foam, and by concentrating on one area you can create some really natural looking surfaces.

Haven't had an opportunity to try it just yet.



Hix


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## ErisKSC (Jun 27, 2005)

*RE: Re: RE: Fake Rock*

Awesome!!!


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## Caveman (Jun 27, 2005)

Thanks guys, it's good to hear they look alright, usually I get the "why would you want to make a rock" response.

Hey Jason and Alexr, i'm down in Vic sorry guys but i'm confident you'll be able to do it. 

Pryor, this rock would have cost around $15. You can expect to pay between $8 - $16 for each 1kg container of pigments and $10 for a pre-mixed bag of sand and cement but this makes a few rocks. You could even just use black and acheieve your color variations using sand.

Tommo, I don't think the thin layer of concrete would hold much water but you can definitly make waterfalls from it.

Browns, I haven't made any hides but I've been thinking about it. Polysyrene has unreal insulating properties.

Hix, Bondcrete is made by Bondall. I use another product but listed this because everyone would be able to find it. It's all much the same.

Cheers everyone.


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## solitarydiver (Aug 31, 2005)

G'Day caveman SPECTACULAR LOOKING ROCKS pat yourself on the back......... She who must be obeyed is copying your design but is getting a little disgruntled and not game to use the bondall as a final sealer. As she is doing a waterfall it needs to be very waterproof and the worry is that by sealing it this way will lose the "rock look". Does this stuff dry clear and will it be good enough for water on it all the time?


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## solitarydiver (Jan 4, 2006)

BUMP.......BUMP BUMP


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## Viking (Jan 22, 2006)

Thanks for the sharing this with us Caveman, I'm in the process of making the rock wall, but unfortunately I'm not particularly artistic so I don't have a great of confidence in how it is going to look. Unfortunately the photo's from your post are down.


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## wombat100 (Jan 23, 2006)

*RE: Fake Rock*



celticskull said:


> thay look great caveman wish i had the time to make some... welldone



why can't I see the rock pictures?


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## Wrasse (Jan 23, 2006)

*RE: Fake Rock*



wombat100 said:


> celticskull said:
> 
> 
> > thay look great caveman wish i had the time to make some... welldone
> ...



Moved or deleted or the host server is down. I can't see them either, so it isn't just you.


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## peterjohnson64 (Jan 23, 2006)

Now that Lutzd has confirmed that you can't link to photos anymore is there any chance, Caveman, of posting the photos. cheers.


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## Caveman (Jan 24, 2006)

Hey Solitarydiver, I tried to avoid water because it would be easy to stuff up and I don't want to be responsible. Bondcrete does dry clear (even undiluted) but you dilute it with water, I wouldn't use it in an amphibian enclosure though.

Note: If you use to much Bondcrete you will smell it and when you hose your rock down it will foam.

If I were to make a waterfall I would seal my base color with Silasec cement or Pondtite and lightly color it with pigments and sand. Don't use a tint or final sealer (the tint is what needs to be sealed in). It would be up to you to decide which one to use and if it's safe for your application. Lime is not safe for fish ponds so be carefull that you don't use a product containing lime.


Other than that the easiest way to go about making a rock like this is to buy a bag of pre mixed render for the base coats (follow the instructions on the packet for curing times etc, but apply it with a paint brush). Then mix small amounts with pigments to get the color you want. I only listed the different materials to give people an idea of what to look for. Render contains additives already so you just add water and color.

Peter, your outdoor enclosure would have been perfect for running amok with concrete rocks.

Here are the pictures in the order they appear originally.


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## peterjohnson64 (Jan 24, 2006)

Hey caveman, where do you live. I would be more than happy to pay to come along to a training day to learn how to make these. You caould have "some that you prepared earlier" and we could provide all of our materials. Maybe even a stand at Phil's reptile expo. and yes mate, I would have loved fake ones in my enclosure but I didn't know how to make them and the pallet of real ones was $200 and the guy wanted $1,000 to make fake ones. But at least when I drop a fake one on my little toe it wont hurt as much. and I still have 3 more outdoor enclosures to decorate yet.


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## Caveman (Jan 24, 2006)

Peter, I'm down in Vic unfortunatly, otherwise I would be glad to show you first hand. Making the rock is easy, shaping it to look like a real rock is the tricky part and this can't really be taught. The best way to learn is to get out there and study real rock formations and practise. I can give you directions on how to make solid concrete rocks though if you'd like? It's a very similar process only you use building rubble as the base instead of polystyrene.

I've been thinking of having a few herp related designs printed onto t-shirts and thought a stand at a pet/reptile expo would be a good place to start. It would be good to join forces with a few people to make one really worthwhile stand offering a range of goods as well as several interesting displays throughout the day to bring people in.


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## beknluke (Jan 24, 2006)

I'm not big into Tshirts - but I reckon that if you made a whole range of different shaped and sized rocks, they'd probably sell!!
Congrats caveman - I really like your ideas!! I think that when I stop being so lazy I might have to get in and make a few myself!!
Question though - do you find that they're so light weight that the herps move them around all of the time? I would be looking at putting them in with adult beardies as a good substitute for the real thing (real rocks and logs weigh too much for my comfort to be in the upper enclosures) but have a feeling that my beardies would re-decorate in a heartbeat!
Cheers 
Bex


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## Surfcop24 (Apr 28, 2006)

Has anyone up near brisbane or the Gold Coast made some good fake rocks.... I'm not game to have a go as I know they will be S##T..... Anyone willing to mafe some for me??? All expenses plus a lil extra of course...


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## dickyknee (Apr 28, 2006)

Caveman , i have just about finished my first set of rocks / rockwalls , i was tossing up between the your idea using the bondcrete/hardener and the tile adhesive / paint option ..... being a builders labourer for alomost twenty years i know how to use all the products well ...so i went with your idea and am extremely happy with them so far ( just a few more highlights then a few clear coats for sealing it ) i will post some pics up when done . 
thanks for the good tip .
Dickyknee .


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## GreatSage (Jun 18, 2006)

Caveman,

Thanks for the Tut just finished my first Rock/background and I love it, thanks
again for sharing.


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