# New Cement Background Method



## melas (Oct 24, 2007)

I have been playing with a rock wall solution that would be strong, light-weight, resistant to cracking, and non-toxic. Also high on my agenda would be that it would be easy to replicate for others with materials widely available via the internet and/or local hardware stores.

Below are some photographs and discussion about my method. Unfortunately this particular model did not turn out as aesthetically pleasing as I would have liked. I used an "old" bag of portland cement which had drawn moisture and was thus full of "lumps". Because of this I did not spend much time sculpting as I new it would never turn out the way I wanted. I use it merely for a model to demonstrate the method. I did end up using it in a terrarium. It was intended to be a pump box cover in my 125 gallon and is working just fine for that purpose. I may replace it at a later time but it actually looks rather natural so who knows.

*SUPPLIES:*

*1 Bag of Portland Cement* ~ $10 for a 50lb bag









*1 Package of Fiberglass Fibers* ~ $5 for a package
Can be purchased here: Amazon.com: Bon Tool Co. Anti-Crack Concrete Fibers: Home Improvement









*1 Gallon of Latex Paint *~ $10 - $30 depending on type
You may want to invest in a "Non-toxic" latex paint that is Ethylene Glycol Free. I have included a report below that suggests that latex modified cement does not leach harmful chemcials but additional caution my be prudent


*METHOD:*

*STEP 1* - Get a mixing container for the cement and put enough portland cement into it that you can have it worked within 10 - 15 minutes as this mix will start to solidify rather quickly. It's helpful to have a mechanical cement mixer of some sort though not necessary. I just used a drill with a paint mixer attachment. Works pretty well!










*STEP 2* - Throw a small handful of cement fibers into the portland cement. You don't need a TON but the more you have the greater spans you'll be able to cross with the cement. I was able to cover 8" gaps with this while building my python cage rock wall.

*notice the large "chunks" in my portland cement - that's from moisture. If you run into this you could sieve the cement to get a nice "sugar" texture from it









*STEP 3* - Add the latex paint to the mixture. I used a 50/50 mix of paint and water. You can play with this to get different results. I used white paint because that's what I had. You could get creative with this and get different colors to create different looks. Remember though that the cement will dilute the color so you'll want to use a darker color than you are planning on having on the finished product!










*STEP 4* - MIX! You'll of course want to make sure the cement is throughly mixed with no dry spots. I molded my model like modeling clay so I went with a "drier" mix . . . you could certainly use a "wetter" mix if you are painting a foam mold etc. 










STEP 5 - SCULPT! I put a piece of foam down to make it easy to make a hollow piece (it had to fit over my pump box). I molded the cement around the foam and just burned the foam out later. 










*STEP 6* - CURING and pH Neutralization . . . I just filled my sink in my reptile room with water. After letting the cement set for about 2 hours I placed the piece into the sink so that it was totally submerged with water. I left it there untouched for 5 days. At that point I flushed the old water and added fresh. I put in about 20% white vinegar to complete the pH neutralization. I only did this for 2 more days as I was not really concerned with the pH of the piece as it was a very small portion of the terrarium it was going in and would have little effect on pH of the soil and water.

*STEP 7* - FINISHING . . . I did not paint this piece as I was unsure if I would actually keep it or not and have found that my pieces color up rather quickly and are often times covered in moss in no time anyhow. The pieces that I have painted in the past were done with non-toxic acrylic paints. You can review my other rock wall threads for detail on this part. 

Depending on how many fibers are used and how fluid the mix ends up being you may have some fibers protruding from the cement. A lighter or torch will take care of those very quickly . . . it's actually kind of fun! 

*COMMENTS:*

*Toxicity* - I have included a link to a scientific study that was conducted on essentially the same method as I have outlined above. The results can be reviewed here. In summary - it appears as though no metals or glycols were leached from the cement in the tests.

http://www.allbusiness.com/environment-natural-resources/pollution-environmental/11468412-1.html

*Benefits* - By using the fibers and the latex we can create a cement that is extremely workable, holds detail well, has increased strength and "flexibility", resistant to cracking and penetration by water, and does not leach harmful chemicals.

.


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## Julio (Oct 8, 2007)

Very sweet work matt!!! Shoudl eb a sticky!!


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## rozdaboff (Feb 27, 2005)

Very cool technique Matt. The fiberglass strands concern me though.

I would definitely recommend treating the end product with a flame to help eliminate and fibers protruding from the surface of the structure (even those that you may not be able to see with the naked eye). Even better would be if you could seal/coat the cement.

Small pieces of the fiberglass projecting from the structure could easily penetrate frog skin - which could introduce bacteria or imbed within their skin. There are reports of snakes developing granulomas on their ventrum months after being housed in enclosures with a fiberglass bottom. The granulomas formed around the small pieces of fiberglass that were embedding in them as they crawled on the bottom of the cage.


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## melas (Oct 24, 2007)

Interesting point Oz . . . something I really hadn't considered. Hitting the strands with a torch essentially burns them away instantly, especially if they are not in a clump but protruding as a single strand . . . would you have the same reservations about nylon strands, as they are also readily available and perform the same function with the cement?


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## rozdaboff (Feb 27, 2005)

I think it depends on the thickness of the nylon, and how stiff it is. Conceptually, the same problem would exist. But, I don't know if it would pose the same potential problem to the frogs.


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## Ed (Sep 19, 2004)

rozdaboff said:


> Very cool technique Matt. The fiberglass strands concern me though.
> 
> I would definitely recommend treating the end product with a flame to help eliminate and fibers protruding from the surface of the structure (even those that you may not be able to see with the naked eye). Even better would be if you could seal/coat the cement.
> 
> Small pieces of the fiberglass projecting from the structure could easily penetrate frog skin - which could introduce bacteria or imbed within their skin. There are reports of snakes developing granulomas on their ventrum months after being housed in enclosures with a fiberglass bottom. The granulomas formed around the small pieces of fiberglass that were embedding in them as they crawled on the bottom of the cage.


I have actually seen this occur in fiberglass exhibits.. and was going to bring it up as a concern. I would also strongly suggest sealing the concrete after singing to prevent wear from exposing further pieces of fiberglass as I have also seen that happen in enclosures. 

Ed


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## VivariumWorks (Feb 27, 2008)

What your describing here is a modified GFRC. This is what rock paneling companies use to make large scale rock exhibits. Its ideal in the sense that its stronger than normal concrete and lighter, and holds up well when put into a rubber mold. Look up GFRC stuff on smooth-on.com and you'll see what I'm talking about.

The issue with the glass fibers is a valid one unless you cast it into a mold. If you do this, the glass fibers will not protrude as the mortar will settle and form a concrete skin immediately adjacent to the rubber and you should not see any of the glass fibers, nor any sticking out. 
However if you use this method as a sculptable medium, I fear the sticking out of the glass fibers can be an issue if not sealed/flamed as suggested.

One trick I've used is to take ground up styrofoam and mix it in with the concrete/grout. This makes a very lightweight material (relatively speaking) and can be layed up and sculpted. When dry, a light layer of wet grout painted over it will hide any of the foam pebbles so you can't see it.

I've worked with fiberglass enough to stay away it. I really don't like them as they hurt something awful and are super irritating to the skin if you get it on you.

Melas, try your method as a casting material and I bet you can get thin light strong rocks.


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## DF20 (Jul 7, 2007)

how do you test to see if the chemicals leaching from the grout/concrete are unsafe? 

what harmful chemicals/ ph level are you looking for?


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## davecalk (Dec 17, 2008)

> *1 Gallon of Latex Paint *~ $10 - $30 depending on type
> You may want to invest in a "Non-toxic" latex paint that is Ethylene Glycol Free. I have included a report below that suggests that latex modified cement does not leach harmful chemcials but additional caution my be prudent


I would recommend that you purchase paint that is classified as "Low VOC" or "Low Volatile Organic Compounds" as concrete will have the ability / tendency in a high moisture environment to allow chemicals to pass through it. Concrete is like a sponge in how porous it is. It will "wick" or draw moisture from high level areas to low level areas. Any chemicals within it may wick from high level areas to low level areas. The latex paint may or may not have the ability to lock the chemicals in place.



> STEP 2 - Throw a small handful of cement fibers into the portland cement. You don't need a TON but the more you have the greater spans you'll be able to cross with the cement.


The fiberglass fibers are used to strengthen the concrete to help keep it from cracking and spalling, but there are drawbacks. They are not made out of nylon as others mentioned. As Ed and others others have shared, you could have real health / safety issues for your animals. If you have ever installed fiberglass insulation, you know that it can cause you to itch as the tiny fibers of glass are scratching and cutting your skin. Also, you do not want to breath it's fibers. Your body does not break down the fiberglass fibers, but it will tend to encapsulate the fibers in your lungs. This would be the same with your animals.





> STEP 5 - SCULPT! I put a piece of foam down to make it easy to make a hollow piece (it had to fit over my pump box). I molded the cement around the foam and just burned the foam out later.


This advice makes me very nervous. Burning or melting foam with a torch or some other heat source should only be done with proper ventilation and with a good chemical inhibiting mask. This is because burning / melting foam with heat produces all kinds of nasty / harmful vapors.




> *STEP 6* - CURING and pH Neutralization . . . I just filled my sink in my reptile room with water. After letting the cement set for about 2 hours I placed the piece into the sink so that it was totally submerged with water. I left it there untouched for 5 days. At that point I flushed the old water and added fresh. I put in about 20% white vinegar to complete the pH neutralization. I only did this for 2 more days as I was not really concerned with the pH of the piece as it was a very small portion of the terrarium it was going in and would have little effect on pH of the soil and water.


It actually takes 21 days for concrete to cure to within 97 percent of it's strength. When cement / concrete is "curing" it is actually absorbing water molecules or hydrating. After about 28 days it is mostly finished hydrating or curing, but cement actually keeps hydrating VERY slowly for an indefinite period. As it hydrates it releases calcium oxide and calcium hydroxide which are two forms of kalkwasser which can majorly screw up the pH in your tank.

Because of this, it is best to soak it in fresh tap water to for 5 to 6 weeks with weekly water changes in order to finish the curing and leaching out the high pH compounds and silicates. Once the concrete is HYDRATED or fully cured, none of the major compounds in cement are particularly harmful in a tank or aquarium. 



> STEP 7 - FINISHING . . . I did not paint this piece as I was unsure if I would actually keep it or not and have found that my pieces color up rather quickly and are often times covered in moss in no time anyhow. The pieces that I have painted in the past were done with non-toxic acrylic paints. You can review my other rock wall threads for detail on this part.
> 
> Depending on how many fibers are used and how fluid the mix ends up being you may have some fibers protruding from the cement. A lighter or torch will take care of those very quickly . . . it's actually kind of fun!
> 
> ...


Most of this is true. The fiberglass fibers do add a great deal of strength and resiliency, but the while the latex paint may slow the leaching process, it will not completely stop the leaching of harmful chemicals or the penetration of water. And if you don't use "Low VOC" paint, you may be adding harmful compounds to the leaching process. Also the amount of paint used to "tint" the rock will vary depending on the color wanted which will affect the percentage of latex paint used in the mix to "fix" or "arrest" the leaching process. Higher amounts of latex may slow the leaching process more.


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## melas (Oct 24, 2007)

davecalk said:


> I would recommend that you purchase paint that is classified as "Low VOC" or "Low Volatile Organic Compounds" as concrete will have the ability / tendency in a high moisture environment to allow chemicals to pass through it. Concrete is like a sponge in how porous it is. It will "wick" or draw moisture from high level areas to low level areas. Any chemicals within it may wick from high level areas to low level areas. The latex paint may or may not have the ability to lock the chemicals in place.


Please read the link I included which includes a study done on the assumptions you make above. Also I actually recommended in my post folks use the NO VOC paint . . . I just called it "Non-toxic" . . . 

From the link . . . 


> *In addition, the leachate obtained from mixtures containing 15% and 25% WLP [Waste Latex Paint] was analyzed to determine any presence of diethylene glycol, ethylene glycol, and propylene glycol, which are harmful ingredients usually incorporated in latex paint formulations . . .
> 
> Moreover, no diethylene glycol, ethylene glycol, or propylene glycol were detected in leachates of specimens from mixtures incorporating 15% and 25% WLP.*





davecalk said:


> This advice makes me very nervous. Burning or melting foam with a torch or some other heat source should only be done with proper ventilation and with a good chemical inhibiting mask. This is because burning / melting foam with heat produces all kinds of nasty / harmful vapors.


Please . . . I have posted many times [though not in this thread] that this needs to be done outside and with ventilation - I hope common sense would take over here. . . I would not see a need to remove the foam in a typical application - this was necessary for what I was doing in this application as this piece is sitting on top of pump box and is only there to prevent frogs from getting into the pump area.

http://www.dendroboard.com/forum/me...k-wall-tank-18x18x24-exoterra.html#post292363

http://www.dendroboard.com/forum/parts-construction/50552-carving-styrofoam.html#post440077

http://www.dendroboard.com/forum/parts-construction/39917-please-help.html#post354307




davecalk said:


> It actually takes 21 days for concrete to cure to within 97 percent of it's strength. When cement / concrete is "curing" it is actually absorbing water molecules or hydrating. After about 28 days it is mostly finished hydrating or curing, but cement actually keeps hydrating VERY slowly for an indefinite period. As it hydrates it releases calcium oxide and calcium hydroxide which are two forms of kalkwasser which can majorly screw up the pH in your tank.
> 
> Because of this, it is best to soak it in fresh tap water to for 5 to 6 weeks with weekly water changes in order to finish the curing and leaching out the high pH compounds and silicates. Once the concrete is HYDRATED or fully cured, none of the major compounds in cement are particularly harmful in a tank or aquarium.


Again I have posted many times about this issue . . . 
http://www.dendroboard.com/forum/me...k-wall-tank-18x18x24-exoterra.html#post292363

http://www.dendroboard.com/forum/parts-construction/50552-carving-styrofoam.html#post440077

http://www.dendroboard.com/forum/parts-construction/39917-please-help.html#post354307

You are correct that it takes several weeks for *concrete* to get within 90%+ full strength. This is "pure" portland cement . . . it reaches 20MPa (near 3000 psi) within 7 days depending on how fine the mix is. True that this is not "full strength" but I am attempting to outline a method that allows folks to do this as easily, quickly and cheaply as possible. With the utilization of the latex and fibers the need for curing with additional water is essentially eliminated anyhow. 

Here's a picture of a 10' long wall I made that received NO additional water after application (mostly because I couldn't find a good way to do it):




























As you can see there are no cracks and I can vouch for the fact that this stuff is CRAZY strong. At a 1/2" thickness I'm able to put my full weight on it as I crawl in and out of the cage for maintenance etc . . . 



davecalk said:


> Most of this is true. The fiberglass fibers do add a great deal of strength and resiliency, but the while the latex paint may slow the leaching process, it will not completely stop the leaching of harmful chemicals or the penetration of water. And if you don't use "Low VOC" paint, you may be adding harmful compounds to the leaching process. Also the amount of paint used to "tint" the rock will vary depending on the color wanted which will affect the percentage of latex paint used in the mix to "fix" or "arrest" the leaching process. Higher amounts of latex may slow the leaching process more.


Again . . . please read the documentation provided. They crushed the concrete and soaked it in acid and found no VOC's in the leachate after 300 frreez/thaw cycles. . .

I'm going to investigate further on the fiberglass . . . I'm not totally convinced that is in an issue after torching the surface (though I do not doubt the words of experienced members such as Ed and Oz that it has posed problems in applications in the past). I'm going to take a piece to a friend and have him look at it under a microscope. In the meantime I checked out the nylon fibers (which I mentioned . . . ) and they appear to be a similar texture to that of a nylon rope . . . soft and almost like cotton. I'm going to do some tests with that as well but I'm sure it will provide similar results when it comes to the prevention of surface cracking etc. . .


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## Ed (Sep 19, 2004)

Hi Matt,

In one Zoological collection, the problems with the fiberglass didn't start for a number of years until after there was some surface wear liberating the ends of some of the fibers. At that point, there were widespread lesions in a number of species which in many of them ultimately caused the death of the animals. That is why I was suggesting sealing the concrete to reduce wear. In addition, really sealing it as you will will also have some difficulty in removing urates from any irregularities in the surface (and if the urates dry you will need a wire mesh brush (or even better a small pressure washer) to scrub them out of the irregularities which abrades the surface... )

Ed


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## melas (Oct 24, 2007)

Thanks for the thoughts Ed. The large enclosure I pictured above was sealed to prevent staining from the giant python poos and also to aid in water proofing the water bowl. However I have never sealed a cement piece used in a terrarium. I'm curious how a millimeter thick coating of sealant would increase the durability of the cement. If the abrasion of an animal is enough to wear away cement how is the thin layer of sealant going to do anything to stop that? 

Also - in the examples you mentioned above are we talking about large animals such as tortoises, boids, varanids, etc or has this occurred with small amphibians such as dendrobatids?


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## Ed (Sep 19, 2004)

The companies that construct enclosures for zoos strongly suggest monitoring the enclosures for wear and reseal them as needed.. 

The wear doesn't have to necessarily come from the animal (although some like varanids can be fairly damaging) but from the routine maintence being done on the enclosure to keep them clean (usually the animal care and maintence is more damaging than the animal). 

It occured across multiple genera and did involve very small animals up to fairly large animals (including some large heavy bodied snakes like a 6.5 foot Eastern Diamondback (and was very nasty attitude..) 

Ed


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## melas (Oct 24, 2007)

Okay I can see how wire brushes could wear it down over several years of maintenance. So in a terrarium with darts I would not be scrubbing the background but merely spraying it with water on a regular basis to flush any organic waste from the surface. The wear would be minimal to non-existent at that point. My terrarium rock walls have all supported a great deal of flora that I assume are consuming the frog waste and urea.

I do think I will pursue the nylon fibers for any future work . . . I'm still going to get some microscope work done on what I've produced just to see if there are any fibers protruding from the surface. I'm fairly certain that they've all been torched off though.

Good to know about the manufacturers recommending monitor of the wear on the backgrounds. So far my snakes have been pretty good about crapping right in the middle of the enclosure so I have yet to need to scrub the rock background. I have two large pieces of outdoor carpet that can be removed for ease of cleaning.


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## Ed (Sep 19, 2004)

Good to hear that you have mats that can be removed. 
In my experience, scrubbing dry urates off can strip the sealant in a few cleanings as oppossed to a couple of years which is why I suggested the power washer.. 
If you can get to it while it is still damp it is easy to remove with a soft bristled brush and this does little wear.. but once it dries it sets to the concrete like.. concrete and can be difficult to remove. 

Ed


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## davecalk (Dec 17, 2008)

Hi Matt,

I hope that my post in no way felt like I was smacking or flaming you. It was not my intention. I apologize if you got that feeling.



melas said:


> Please read the link I included which includes a study done on the assumptions you make above. Also I actually recommended in my post folks use the NO VOC paint . . . I just called it "Non-toxic" . . .


Yes, you did say "Non-toxic", I just wanted to clarify. I have been a paint contractor and general contractor, and over the years I have seen paint labels say all kinds of things. Many folks and newbies wouldn't really know what "non-toxic" should look like in a paint product. "No VOC" does indicate that the paint does not contain / emote "Volatile Organic Compounds" which is good, as these can be detrimental to health frog or human. 

The fact that they call the paint "WLP" or "Waste Latex Paint" implies to me that they are using recycled paint which is in no way "Low VOC" or "No VOC" If they indeed are using "Metro recycled paint" and they found no leaching of chemicals that is a plus for the process.




> Please . . . I have posted many times [though not in this thread] that this needs to be done outside and with ventilation - I hope common sense would take over here. . .


I am glad. The one thing that I have found over the years is that sometimes "Common Sense" is not all that common. If folk do not have the back ground, as from your posts I see that you do, they might not even think of the potential health issues that can arise from breathing melted foam. 




> You are correct that it takes several weeks for *concrete* to get within 90%+ full strength. This is "pure" portland cement . . . it reaches 20MPa (near 3000 psi) within 7 days depending on how fine the mix is. True that this is not "full strength" but I am attempting to outline a method that allows folks to do this as easily, quickly and cheaply as possible.


I think that what you are trying to do is excellent, and I applaud your efforts. I value folks that are researching, learning and posting what they have learned.




> With the utilization of the latex and fibers the need for curing with additional water is essentially eliminated anyhow.


I have read the article, and I hope what you say is true, but the scientist in me is not ready to buy into to the whole statement that adding latex paint will eliminate the need for the concrete product to be cured over time before it is completely safe. Concrete only cures in the presence of water. If you remove the water, the process stops. There is a chemical and structural change in the concrete and the process does produce some harsh chemicals as a by-product. The technique does show promise, but I think that time and experimentation are needed to prove that adding paint changes the curing process. 

Personally I am guessing that the addition of paint may form a binding / blocking barrier that makes it harder for the leaching chemicals to escape, but the chemicals that are produced are very harsh. (I've had my hands cracked and split open to the point of bleeding many times from pouring concrete on days that I forgot my gloves.) I wonder whether they might over time break down the barrier and whether the paint might just be slowing the migration process of the chemicals. Don't know.



> Here's a picture of a 10' long wall I made that received NO additional water after application (mostly because I couldn't find a good way to do it):


That looks marvelous. 

A simple and easy way to water it and keep it moist would be to use a garden sprayer to mist the wall. If it were me I would error on the side of caution and mist it. Having worked with concrete for over 30 years I would not want to bet the farm on a project of this magnitude on a new and unproven technique. You have done tons of work. I would hate to see that work be spalled off in a year or two for lack of keeping the wall moist. A little misting couldn't hurt anything and it might help. 




> Again . . . please read the documentation provided. They crushed the concrete and soaked it in acid and found no VOC's in the leachate after 300 frreez/thaw cycles. . .


I did read the article and the fact that they ran it through 300 freeze / thaw cycles and got no leaching is positive.



> I'm going to investigate further on the fiberglass . . . I'm not totally convinced that is in an issue after torching the surface (though I do not doubt the words of experienced members such as Ed and Oz that it has posed problems in applications in the past). I'm going to take a piece to a friend and have him look at it under a microscope. In the meantime I checked out the nylon fibers (which I mentioned . . . ) and they appear to be a similar texture to that of a nylon rope . . . soft and almost like cotton. I'm going to do some tests with that as well but I'm sure it will provide similar results when it comes to the prevention of surface cracking etc. . .


I think that experimenting with the nylon fibers is a good idea.

Once again, sorry if I came off as raining on your parade, it was not my intent. With my background, I do see some potential issues that the average bear would not see. 

Please keep us informed on your progress.


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## melas (Oct 24, 2007)

davecalk said:


> Once again, sorry if I came off as raining on your parade, it was not my intent. With my background, I do see some potential issues that the average bear would not see.


No parade here . . . the way I read what you wrote it seemed as though you were conveying your opinion before reading the documentation I supplied. No worries. 



davecalk said:


> The fact that they call the paint "WLP" or "Waste Latex Paint" implies to me that they are using recycled paint which is in no way "Low VOC" or "No VOC" If they indeed are using "Metro recycled paint" and they found no leaching of chemicals that is a plus for the process.


This is the way I took it as well and the reason I did not provide further detail. The NO VOC paint would provide a path for those intensely concerned with the possibility of toxic leachate.



davecalk said:


> I am glad. The one thing that I have found over the years is that sometimes "Common Sense" is not all that common. If folk do not have the back ground, as from your posts I see that you do, they might not even think of the potential health issues that can arise from breathing melted foam.


Eh . . . clean up the gene pool when you can is what I say! 



davecalk said:


> I have read the article, and I hope what you say is true, but the scientist in me is not ready to buy into to the whole statement that adding latex paint will eliminate the need for the concrete product to be cured over time before it is completely safe. Concrete only cures in the presence of water. If you remove the water, the process stops. There is a chemical and structural change in the concrete and the process does produce some harsh chemicals as a by-product. The technique does show promise, but I think that time and experimentation are needed to prove that adding paint changes the curing process.
> 
> Personally I am guessing that the addition of paint may form a binding / blocking barrier that makes it harder for the leaching chemicals to escape, but the chemicals that are produced are very harsh. (I've had my hands cracked and split open to the point of bleeding many times from pouring concrete on days that I forgot my gloves.) I wonder whether they might over time break down the barrier and whether the paint might just be slowing the migration process of the chemicals. Don't know.


Don't take my word for it. Do some research on latex/polymer modified cements/concretes. They've been widely used for decades. You will see that this is exactly what happens. Latex acts to bind the water molecules in the concrete, preventing it from desiccating and thus allowing hydration to occur. 

The product I used to start the python cage was actually a proprietary mixture designed for use on the exterior of houses. I installed it per their instructions and I guarantee you that it does not need additional water. What I have done is attempt to replicate a "poor man's" version of this system. The "water" bowl and flat areas under the doors in python cage utilize the design outlined above. 



davecalk said:


> Having worked with concrete for over 30 years I would not want to bet the farm on a project of this magnitude on a new and unproven technique. You have done tons of work. I would hate to see that work be spalled off in a year or two for lack of keeping the wall moist. A little misting couldn't hurt anything and it might help.


Again this background utilized a proprietary formula that I then replicated with easily found materials to complete the water bowl and the flat areas under the doors. It is certainly not "unproven". Also - in a previous life I worked for a Geotechnical firm as a field engineer. I was responsible for making sure contractors with 30 years of experience D) installing foundation systems did so properly for clients such as Lowes, Kohls, Target, Walmart, etc. I conducted numerous tests: Nuclear Density, Compression, Slump, Cores, etc on a daily basis . . . I'm no concrete chemist but I do have a fair understanding of how it all works . . .


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## davecalk (Dec 17, 2008)

melas said:


> Don't take my word for it. Do some research on latex/polymer modified cements/concretes. They've been widely used for decades. You will see that this is exactly what happens. Latex acts to bind the water molecules in the concrete, preventing it from desiccating and thus allowing hydration to occur.


No need for me to research it, I have used latex polymers to modify concretes for years. Heck, I have some Acryl 60 sitting in my living room right now. Using it for some experiments for creating artificial vines and things.




> The product I used to start the python cage was actually a proprietary mixture designed for use on the exterior of houses. I installed it per their instructions and I guarantee you that it does not need additional water.


That's great. I didn't know that from your write up and photos. I thought that you had built the entire wall system using the paint add-mix. With your background, I'm sure that you know that even if you are using an acrylic concrete bonding / strengthening agents, most manufacturers still recommend either using a surface sealer, such as Thoroseal, which would keep the moisture locked in so that proper hydration takes place with no additional water being needed or you cover the wall with plastic to keep the moisture in, or you regularly rehydrate the wall by spraying it. The big issue with most of the surface sealers is that most of them are solvent based which means that they probably are not going to be safe for our frogs and tanks. That is why I recommended spraying down your wall with water. Also, most of these surface sealing products are designed to disappear over time; they are not design to be used as a permanent lifelong sealer.




> What I have done is attempt to replicate a "poor man's" version of this system. The "water" bowl and flat areas under the doors in python cage utilize the design outlined above.


I think that is great. I am always looking for better, more cost effective ways of doing things.




> Again this background utilized a proprietary formula that I then replicated with easily found materials to complete the water bowl and the flat areas under the doors. It is certainly not "unproven".


No, the use of Concrete Acrylic Polymers are not "unproven", but using paint as an acrylic substitute is unproven. Whether it will function long term in the same manor as the regular concrete acrylics is an unknown. 

Plus Matt, when you made the statement that with the "utilization of the latex and fibers the need for curing with additional water is essentially eliminated" it made me think that you were a concrete newbie. (Clearly from your previous life, you are not.) but I don't think that it has been proven yet that adding paint to concrete eliminates the need for curing. I wouldn't trust that the concrete would be safe for our frogs and plants without seeing a lot more data. 

Matt, the fact that you ran through the curing process that you did, shows that you really didn't trust that the uncured concrete would be safe either. I just didn't want to see a newbie taking your statement as the gospel truth and them possibly losing some frogs because of it. 

Hope that makes sense.


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## gluedl (Oct 8, 2008)

Hi all

just red the thread and was thinking why not substitute the glass fibers for something else, too. Even if they are flamed, there might be some spikes remaining that can scratch badly. And as for the nylon, it will reinforce but will not stick to concrete as will the fibers. Why not use something more natural like hemp fibres or even coton fibres (last one might not last that long as they might rot away). Both have been used intensively around here in the last years for building eco houses...

just my 5 cent

Have a nice day

gluedl


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## frankpayne32 (Mar 17, 2007)

If done properly the fiberglass method is the best way to make exhibits IMO. But, if done properly it is prohibitively expensive for most private individuals. Here are some examples of exhibits made by the company I work for. Some are a decade old at this point and are still holding up without cracking.


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## Julio (Oct 8, 2007)

great exhibits!!!! gotta love that tree trunk


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## frankpayne32 (Mar 17, 2007)

Julio said:


> great exhibits!!!! gotta love that tree trunk


Thanks, I will pass the praise along. Our fabrication guys are the absolute best.


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## froggerboy (Jul 9, 2006)

what do you mean by done properly? also what is the estimated expense and how does that compare to the price of polygem epoxies? I'm trying to finish a waterdragon enclosure and I don't want to ship anything in.


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## froggerboy (Jul 9, 2006)

would an epoxy resin top coat be sufficient to prevent expose to the fiber glass?


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## postskunk (Jul 19, 2009)

this might be a silly question but is is possible to go the other way with this. Meaning could you mix up some concert or grout then either mix up a laminating resin with a small amount of the Catalyst enough to cure it but not as fast as normal and combine the two, or even mix in the laminating agent in then when everything is set up mix in the catalyst just before the application? The purpose would be that hopefully you could gain the rock like texture with a more solid and light weight product and use a minimal amount of laminate which would keep costs down?

forgive me if I'm confusing material names I get a little confused buy all the different types of epoxy I'm referring to marine grade fiberglass resin

also this is a little bit off topic and my have been discussed somewhere else at some point in time but when leaching concert is it more efficient to use RO water since the RO has a tendency to suck out minerals and nutrients that it has been previously derived of?

thanks
-Matt


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## froggerboy (Jul 9, 2006)

here's something I found: RetailSource: Fiber Reinforced Concrete. this is probably more useful for those who seek larger than normal structures.


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## VivariumWorks (Feb 27, 2008)

GFRC is a total pain doing it by hand unless you've worked with the method a lot.

I've tried it a few times and found it a serious pain, and the end weight is still too high. For structural purposes it works and is light but for vivarium purposes its still very heavy.

You could use a thin layer of concrete/grout and shore it up with a stronger material like a resin, epoxy, or foam. 

Or if your coating something, you can mix your epoxy with a dry grout mix.


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