# a few questions about the cracked cork mosaic method.



## thedudeabides (Mar 3, 2015)

I have been looking into creating a cracked cork mosaic for one of my 18x18x24 tanks and have a few questions.

1. I want to create a surface that is not so vertical with different tiers. What is the best way to accomplish this? I was thinking for the lowest layer I may create a wall with egg crate and fill the back side with hydroballs abg and leaf litter essentially just raising the floor a couple of inches in the back of the tank.

2. the next tier I was thinking of putting down great stuff first then pressing the cork into it to give it maybe an extra inch or two off the wall. Then the 3rd tier would just be siliconed directly to the wall.

3. The cork pieces I am using are not perfectly flat. Should I carve some out of the back of them to make them more flat? From what I understand you want to have the cracks in between the cork pieces to be as deep as possible so I think I already know the answer. Also If they are not flat should I attempt to fill in the gaps between the wall and the cork? Would I use sphagnum moss to do this or GS?

4. The tank I am using had a clay wall previously. How should I go about cleaning the glass so the silicon sticks best? I am thinking just rinse it out real well then finish with rubbing alcohol. 

Sorry for the book but does it seem like I am on the right track? Did I miss anything that I should consider?

Thanks for your time.


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## Encyclia (Aug 23, 2013)

Good questions 



thedudeabides said:


> I have been looking into creating a cracked cork mosaic for one of my 18x18x24 tanks and have a few questions.
> 
> 1. I want to create a surface that is not so vertical with different tiers. What is the best way to accomplish this? I was thinking for the lowest layer I may create a wall with egg crate and fill the back side with hydroballs abg and leaf litter essentially just raising the floor a couple of inches in the back of the tank.
> 
> ...


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## thedudeabides (Mar 3, 2015)

Thank you for the reply!

Most of it makes sense but I am not sure what you are trying to say here:

"You could do this. I think what I would do (and have done) is to do the background as usual where you silicone your flats back there and then cram the sphagnum all the way around, including at the bottom against the egg crate. This gives you the base layer that you want against the back wall AND makes sure there are no gaps that frogs can get in to get back behind."

Could you please explain further or do you have a photo of this?


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## Encyclia (Aug 23, 2013)

thedudeabides said:


> Thank you for the reply!
> 
> Most of it makes sense but I am not sure what you are trying to say here:
> 
> ...


I don't have a picture handy, but I am just saying that if you want a more 3D look, you can either use more rounded flats for the mosaic on the back or you can do a very flat background using flat cork bark first, then come along after that and add another layer of rounds or roundish flats that sticks our further away from the back. The void spaces in the rounds can be filled with Great stuff topped with sphagnum. This way, it's easier to completely eliminate any gaps in the back-most layer that the frogs can use to get in behind the layer (that's my biggest concern when I make one of these backgrounds. So, you just put down a usual cork mosaic layer first, then layer onto that any 3D stuff you want. Does that make sense?


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## rjs5134 (Feb 1, 2017)

I followed Encyclia's directions on 1 tank like this last year. I just applied silicone to the "high spots" on the back of the cork flats and stuck to the glass. I left an inch or so in between each piece and filled the space between with wet sphagnum. I did not force the sphagnum behind the cork because I was afraid I would pop the cork off the glass. It came out great, the pair of leucs have found a couple of spots they like to spend time and the plants are growing well and spreading all across the tank. I plan to do another similar build soon.


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## thedudeabides (Mar 3, 2015)

Encyclia said:


> I don't have a picture handy, but I am just saying that if you want a more 3D look, you can either use more rounded flats for the mosaic on the back or you can do a very flat background using flat cork bark first, then come along after that and add another layer of rounds or roundish flats that sticks our further away from the back. The void spaces in the rounds can be filled with Great stuff topped with sphagnum. This way, it's easier to completely eliminate any gaps in the back-most layer that the frogs can use to get in behind the layer (that's my biggest concern when I make one of these backgrounds. So, you just put down a usual cork mosaic layer first, then layer onto that any 3D stuff you want. Does that make sense?


Yes Thanks!


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## Ed (Sep 19, 2004)

I'm always curious as to why people fill the back area behind the cork with a material that is going to break down and leave gaps eventually. Wouldn't it make more sense to add something that will also drain but not break down like Turface? 

some comments 

Ed


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## Encyclia (Aug 23, 2013)

Ed said:


> I'm always curious as to why people fill the back area behind the cork with a material that is going to break down and leave gaps eventually. Wouldn't it make more sense to add something that will also drain but not break down like Turface?
> 
> some comments
> 
> Ed


Are you talking about the void behind the cork along the back glass, Ed, or the sphagnum used in the gaps between the pieces of cork? I don't use anything behind the cork and just leave the voids at the back empty. I cram the gaps with sphagnum tight enough that there hasn't been any breakdown in my tanks in the two or three years that I have had them set up. Maybe it is packed tight enough that it doesn't really saturate that much and slows down the break down, but it looks and feels the same in there as when the tanks were started. Not sure why it works, but it does in my case, at least. No frogs have been able to get behind the background in my tanks yet.

Mark


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## Andrew Lee (Jan 21, 2014)

I'm pretty sure Ed is talking about the sphagnum moss behind the cork. Maybe someone should try turface and sphagnum moss and compare the results.


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## Encyclia (Aug 23, 2013)

Andrew Lee said:


> I'm pretty sure Ed is talking about the sphagnum moss behind the cork. Maybe someone should try turface and sphagnum moss and compare the results.


That makes sense. I may not have written the description well, but I wasn't suggesting filling the whole volume behind a cork stump (or whatever) with sphagnum. In that case, I would usually fill it with Great Stuff up to about 1 inch from the top and fill the rest with sphagnum. That is just so I can plant things on it if I want to. Turface would work just fine, too. I usually would just plant things that would be ground cover or whatever in that situation. I wouldn't plant something that rooted deep up there, but with Turface, there's no reason it couldn't be done. 

Mark


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## Pumilo (Sep 4, 2010)

When I have done DendroDave's cracked cork mosaic method, (which I have also incorrectly called the cork bark mosaic method), I never tried to fill the gap between the glass and the cork. The goal is simply to fill the 1/2" to 1" gap between one piece of cork to the next.
My original 75 gallon vivarium using this method, is still up and running at a local friend's house. It was created just over 7 years ago. Paul, the current owner of the viv, has not had to replace any sphagnum moss.
If you use a quality sphagnum moss, it will generally begin growing, thus continually replenishing itself. In spots where it is not growing, you still get other growths, like peperomia roots, brom roots, orchid roots, or just whatever epiphytes you are growing, that seem to grow well enough to lock things in place, and to replace what gradually rots away. This is what I will be relying on, as I have sterilized all the sphagnum in my new build. I have too many tiny things to allow sphagnum moss to infringe upon them. This method was born for epiphytes and mosses, so it is a reasonable assumption that anybody employing this sytem will be using a good amount of epiphytes. 

Further, the system in general, encourages a slightly moist wall, rather than a wet wall, if you are doing it right. I mean, sure, it's possible to overwater anything, but you have to really try to overwater this. Water falls down. The sphagnum on the walls is all completely vertical. A very sizable portion of your misting tends to fall right by your sphagnum. I my experience, this tends to make moist walls, rather than wet. In fact, on a three foot tall wall, this has become a problem I have to address. I find that on my three foot tall wall, I am not getting enough moisture to the bottom third of the walls. I will be modifiying this with the addition of two, hidden, wall mounted misting nozzles. Plus, if people have been paying attention the last 10 years, it shouldn't get that wet. Soggy and stagnant is out. By now, hopefully most have accepted that we need to dry things out some, and get that air moving. 90% humidity, with 6, 45 second daily rainstorms, and everthing dripping wet, should be a thing of the past. Moist sphagnum seems to last much longer than wet sphagnum does.

Anyway, we have a confirmed 7 year lifespan, and still going strong, with no signs of needing touch up work.


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## jarteta97 (Jun 13, 2014)

I'm glad to hear that the 70 gallon is still up Doug, that was a beautiful build. Does your friend have any update pictures? From what you've said, it really does serve as a prime example of this kind of background technique. I also love the centerpiece cork placement.


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## ibarran (Jan 5, 2015)

I'm in the process of building (2) 20 Gallon verts and wanted to make good use of the hieght. I used a miter saw to make some slightly angled cuts the ends of some cork flats so I could securely glue them to the glass and make shelves. Once the glue dried I used GreatStuff Pond Foam to fill in the gaps and even put some underneath the shelves for extra support.


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## jarteta97 (Jun 13, 2014)

Yeah, I had some malaysian driftwood that wasn't even close to flat in the back. I used a table saw as well, took maybe 2 1/2 inches. What's awesome is that the piece I cut off was the perfect size (and now flat) to put on the background, so I essentially turned one piece into two.


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## ibarran (Jan 5, 2015)

Definitely helps have a good tool collection for this hobby. You never know what you're going to need.


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## Pumilo (Sep 4, 2010)

jarteta97 said:


> Yeah, I had some malaysian driftwood that wasn't even close to flat in the back. I used a table saw as well, took maybe 2 1/2 inches. What's awesome is that the piece I cut off was the perfect size (and now flat) to put on the background, so I essentially turned one piece into two.


I like to do that, too. It's not an easy cut, but I like to cut cork bark tubes in half, lengthwise. Each one becomes half a tree, protruding from the sides or back of the viv. You can manipulate the cut, somewhat diagonally. When you wall mount them, one has a lot of trunk at the base, but the top seemingly disappears into the jungle, right at the wall. The other piece you may see no trunk at all. Rather, it gives the effect of a partially fallen tree, or a large branch, leaning/hanging into the viv.

Larger tubes can be quartered. Each quarter goes in the back right or left corner, for a unique corner tree, where the rest of the tree disappears into the jungle, where it is cut off by the glass wall. That lets that single cork round become a tree for 4 different vivs.

Using power tools to cut uneven tubes, especially larger ones, lengthwise is not easy. It presents unique challenges to make sure it is properly clamped and braced. If it's not done properly, kickback can occur, and fingers can be lost. I believe the safest way to cut tubes is with a very large bandsaw, and a homemade jig called a "sled". That method is beyond most home shops. If you choose to do this, whatever method you choose, be safe.


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## Ed (Sep 19, 2004)

Encyclia said:


> Are you talking about the void behind the cork along the back glass, Ed, or the sphagnum used in the gaps between the pieces of cork? I don't use anything behind the cork and just leave the voids at the back empty. I cram the gaps with sphagnum tight enough that there hasn't been any breakdown in my tanks in the two or three years that I have had them set up. Maybe it is packed tight enough that it doesn't really saturate that much and slows down the break down, but it looks and feels the same in there as when the tanks were started. Not sure why it works, but it does in my case, at least. No frogs have been able to get behind the background in my tanks yet.
> 
> Mark


I was referring to the empty sections behind the cork. I guess since I tend to look to have stable enclosures up and running for as long as possible (I still have the same tans running since 2005) and working with exhibits in a zoo, I experienced the voids becoming hollow due to decay which in a few cases resulted in areas where animals could get trapped. 

some comments 

Ed


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## Cakers (Sep 10, 2017)

Have any of you used Dryloc masonry paint on background? I thought I would try doing something that looks like roots coming out of a bank. I heard you can use masonry tint to color the paint. Since its latex based thinking of using latex art paint. I also put sand over great stuff foam and got interesting effect.


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## Cakers (Sep 10, 2017)

Im using a panel that came with the exo so if it doesn't work i can have a do over.


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## serial hobbiest (Mar 5, 2017)

Cakers said:


> Have any of you used Dryloc masonry paint on background? I thought I would try doing something that looks like roots coming out of a bank. I heard you can use masonry tint to color the paint. Since its latex based thinking of using latex art paint. I also put sand over great stuff foam and got interesting effect.


Yes, I made two Drylok "rocks" for my background. You can go with the masonry tint if you want to, but this limits your color selection & likely forces you to buy 1000x times more than what you'll actually be using. I chose to do my tinting with acrylic hobby paints. You can mix them right into the Drylok, achieving whatever colors you want. Just grab a bottle of black, and a few of the darkest colors available. If you want something super dark, you might be better off to grab that black masonry tint, however.


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## serial hobbiest (Mar 5, 2017)

Cakers said:


> Im using a panel that came with the exo so if it doesn't work i can have a do over.


Scrap that panel NOW. You'll hate it, I promise.
I've been a shift supervisor/ engineer in a plant that manufactures that stuff for over 20 years now. That panel is a material called expandable polystyrene (EPS), and you should notice something about it- that it's composed of beads of foam that are fused together (and probably not very well). Over time, this stuff will wick moisture into it where it will be locked, eventually getting stinky, gross, moldy, and heavy. Not to mention, the way that panel comes as-is, doesn't appear to have any sealant over it. It might be fine in a dry, reptile environment, but I would never trust it with my frogs. 

For your foam panelling purposes, go grab a sheet of EXTRUDED polystyrene (XPS) from the hardware store (you know- the pink or blue stuff). It's available in different thicknesses, in 2'x8' or 4'x8' sheets. If you want thick, simply use polyurethane glue to slap together a few pieces. (Wood glue will never set- I tried. Lightly mist the sheets you're gluing, then completely cover with a thin film of polyurethane glue, and apply a lot of weight while it sets). This foam won't soak up anything, and a knife will carve it much more cleanly. Get creative and paint it with your Drylok. 

Have fun, and be frog-safe


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## Cakers (Sep 10, 2017)

Wow thats good to know. I'll take your advice. I was thinking of adding latex art paint since I do art work that will expand my choices.


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## serial hobbiest (Mar 5, 2017)

Cakers said:


> Wow thats good to know. I'll take your advice. I was thinking of adding latex art paint since I do art work that will expand my choices.


I can't comment on whether or not that paint would be safe to use, or what it might do when mixed with Drylok. Acrylics on the other hand are known to be safe, but should be coated with a sealant to improve durability & longevity in such a wet environment (mixing with Drylok takes care of this). The last thing you want are paint particles disintegrating and flaking off into the vivarium, where a frog may accidentally ingest some.


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## thedudeabides (Mar 3, 2015)

So here are the pics of the first cork bark mosaic I did. Planing on doing this for my second terrarium shortly. What do you all think?


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## jgragg (Nov 23, 2009)

> Using power tools to cut ... safest way to cut tubes is with a very large bandsaw, and a homemade jig called a "sled" ... be safe.


Good points. Band saws are nice, but as you note, not in most people's toolbox so to speak. For that matter neither are table saws, or as they could be known, "finger eaters". Ha ha. (But you can rig a sled for a table saw too.)

For cutting cork in "retail sizes" my go-to tool is this:
https://www.protoolreviews.com/tools/ridgid-jobmax-12v-multi-tool/1588/


With the longer plunge-blade attached, it's great for cleaning up the backs of flat pieces so they don't rock or wobble on glass, but instead lay evenly (even if there is a void - you just make the edges flat). 
It's also good for establishing "break-lines" from the backside of bigger flats, to better control what happens when you go to take off smaller pieces from the larger flat. (I usually lay the flat face-down on a 5-gal bucket rim, and push down to make the break. It's easy to tell when and where you need to make the "break-lines" deeper with the saw.) This helps avoid unsightly (IMO...) clean-cut edges. 
With the semi-circular blade attached, it's not bad for ripping tubes. Even if you just use that not-so-deep blade to establish your kerf, then finish up with the longer plunge-blade.

The tool is very easy to control. The biggest health risk is probably the cork dust. These blades have tiny teeth. I wear a mask, and of course eye protection. Leather gloves might be smart.



> a material called expandable polystyrene (EPS)


EPS sucks. Just the annoying static cling of the little balls that pop off when cutting drive me up the wall. Let alone the permeability and - probably - toxicity. The only thing I use it for is as filler in very large "fake rock" builds. I bury it under XPS and GS and seal the whole affair in epoxy. In the past I have used Drylok, and grout, and silicone, in different builds. I like epoxy the best. Then drylok. Grout & silicone last, for different reasons; probably in that order though.



> So here are the pics of the first cork bark mosaic I did. Planing on doing this for my second terrarium shortly. What do you all think?


I think if you and your animals are happy, I'm happy. It's a little "orderly" or "man-made looking" for my taste, but hey, *to each their own*. If you're _really_ looking for another opinion - the long skinny horizontal piece might do well rotated onto the tank's left side, same elevation, or perhaps at the same elevation as the left half-round. Push it almost to the back corner, to serve as a ledge. Then I'd arrange the other smaller pieces so they're not so much in 2 rows but a little more random. Definitely use/spread out the biggest pieces first, then add the smaller ones to fill in.

I do appreciate how you've maintained the bark furrows running up and down like they do in nature. I'd keep that (except for the ledge piece of course).

Have fun!


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