190 replies to this topic

[Gregory2455]

It would be for fun! Also, like I said, smaller scale. I would only try for maybe a couple millimeter tall formations, and that itself may take years...

Edited by Gregory2455, December 27 2014 - 2:03 PM.

[dspdrew]

I setup a couple tests to see if I can solve this erosion problem.

 

I took a piece of a synthetic chamois that seems to be made from something very similar to a PVA sponge, and laid it down on the floor of the container, and then poured new Hydrostone over that. I just want to see what this will do to the path of the water. I ultimately have an idea that could possibly help, I'm just not sure because I'm not an expert in physics. I want to test it out each step of the way, just to get an idea of how each part of this idea affects the water flow and erosion. I filled the container with peat moss again like I did the first time I discovered this problem while testing my cricket bin idea. This moves a large amount of water through the Hydrostone, speeding up the process. It took less than eight hours to bore a pin hole right through 1/4 inches of Hydrostone last time, so this should give me a good comparison.

 

I also put a 3mm layer of Hydrostone in the bottom of one of the tanks as discussed here (http://www.formicult...-7-2014/?p=9783). This should allow the Hydrostone in the tank to change the pH of the water so it will be the same as the Hydrostone it's passing through. If this is mainly caused by the pH of the water, then this might help. Once the other test is finished I'll give this one a try. This should give it plenty time to change the pH of the water.

 

I have also ordered a bisque tile, which is an unglazed ceramic tile. These should absorb water and act a lot like Hydrostone. Since these are not cement based, and very hard, I suspect they will not have this erosion problem. I'll be test this out once it arrives.

[dspdrew]

At first I thought adding the Hydrostone to the bottom of the water tank solved the problem, but now I don't think it did. The one I "fixed" has been getting a larger and larger pinhole through the Hydrostone bottom every day, even though it has Hydrostone in the bottom of the water tank. Today this hole was even larger. You can read the details about this over on my formicarium #5 thread (https://www.formicul...1-2015/?p=10579).
 

I also had a little test going for the last two days, and it's really just left me even more confused.
 
I poured two small blocks of Hydrostone with strips of a synthetic chamois dipped in them, and set them up like this.

 

 
 
After two days, you can see how much more erosion occurred around the chamois strip on the one without Hydrostone in the bottom of the water container.
 
This is the one without Hydrostone in the bottom of the water container.
 

 
 
This is the one with Hydrostone in the bottom of the water container.
 

 
 
I noticed a lot of white crusty deposits forming on the Hydrostone blocks also. I'm not sure what causes this.
 

 

 
 
I've also noticed for a while now that whenever there is anything like a sponge or whatever soaking up the water and transferring it to Hydrostone or Ytong, tons of tiny little bubbles form all over everything in there the way carbonated water does.
 

 
 
I'm not sure what all of this means. Maybe someone can help me figure this out.

[Crystals]

Those white deposits are what are called "sweat". That is what I was referring to when I mentioned hydrostone sweat. It has been recorded in a number of journals, although the nests were setup a lot like my mine (flat with a water chamber on top).

Did the bubbles develop within the first 1-3 hours? If so, then it was just from the water, I see it all the time when I pour a glass of water
If it occurred after 5 hours, then it is likely something else - maybe the hydrostone releasing very tiny bubbles of air from deeper in hydrostone?

[dspdrew]

The Hydrostone does release small bubbles as water soaks into it, but these appear on every surface in the containers that don't even have Hydrostone in them.

[kellakk]

What it looks like to me is that some chemical reaction is occurring and forming precipitate deposits on the hydrostone.  I'm no industrial chemist so I have no idea what, but that may help you focus your search for an answer.  The bubbles could be a gaseous product of whatever reaction is occurring.  If you have access to a highly sensitive digital balance, you should mass the hydrostone blocks before and after to see if those bubbles actually are a product of some reaction.

Edited by kellakk, January 22 2015 - 1:12 PM.

[dspdrew]

I recently read the MSDS of Hydrostone and to my surprise, it's actually made up of more than 95 percent Plaster of Paris (Calcium Sulfate Hemihydrate) (CaSO4•½H2O)

 

You can see the MSDS for yourself here (http://www.usg.com/c...en-52140052.pdf).

 

I posted this problem on a Physics/Chemistry forum (https://www.physicsf...-cement.793777/), and at the time of this post have been told this is simply due to the Plaster of Paris dissolving in the water, and that possibly saturating the water may solve the problem.

 

I also found this (http://www.howtoclea...is-from-cement/), where they claim that the way to dissolve Plaster of Paris is to use something acidic. According to one of the commenters, this information is incorrect and only copied from another incorrect source. He says he experimented and could not get anything acidic to dissolve the plaster, but instead dissolved it with something at the other end of the pH scale. He also says this correct information is impossible to find on the internet. I even found what I suspect was a post of his over on the very Physics forum I posted my question on where he actually corrected all of them on the answer, with not one rebuttal. Unfortunately, this doesn't leave me too confident in the help I'm going to receive over there...

[dean_k]

In other words, you opened a can o' worms...

[kellakk]

I recently read the MSDS of Hydrostone and to my surprise, it's actually made up of more than 95 percent Plaster of Paris (Calcium Sulfate Hemihydrate) (CaSO4•½H2O)

 

You can see the MSDS for yourself here (http://www.usg.com/c...en-52140052.pdf).

 

I posted this problem on a Physics/Chemistry forum (https://www.physicsf...-cement.793777/), and at the time of this post have been told this is simply due to the Plaster of Paris dissolving in the water, and that possibly saturating the water may solve the problem.

 

I also found this (http://www.howtoclea...is-from-cement/), where they claim that the way to dissolve Plaster of Paris is to use something acidic. According to one of the commenters, this information is incorrect and only copied from another incorrect source. He says he experimented and could not get anything acidic to dissolve the plaster, but instead dissolved it with something at the other end of the pH scale. He also says this correct information is impossible to find on the internet. I even found what I suspect was a post of his over on the very Physics forum I posted my question on where he actually corrected all of them on the answer, with not one rebuttal. Unfortunately, this doesn't leave me too confident in the help I'm going to receive over there...

 

Doing some quick searches on reactivity of CaSO4 revealed that it can and does react with sodium bicarbonate (baking soda). I'm not convinced though that it's due to pH, it's likely linked to the chemical structure of Na2HCO3.  What was the pH of the water when you measured it?  Also, Plaster of Paris does not dissolve to this extent in water.

[dspdrew]

What you say makes a lot of sense. The pH of the water, if I can remember right, I think was somewhere right around 7.

[dspdrew]

I did some tests on a few different materials: Red brick, bisque ceramic tile, cement, and unsanded grout.
 

 
 
After a few days of soaking up water, I didn't see any erosion or corrosion of the brick, ceramic tile, or cement. The sponge on the grout almost looked like it had maybe started to make a slight mark, but I really can't say for sure.
 
The red brick actually soaked up water pretty well, and eventually the whole piece was wet.
The tile as I think I have already mentioned, soaks up water very well, leaving the entire thing wet.
The cement soaked up water slightly, but not really enough to wet the entire thing.
The grout seemed to have soaked up water about the same amount as the cement--not much at all.
 
The first two are both technically ceramics, and both had pretty much the same results. The second two are technically both cement, and also seemed to have pretty much the same results.
 
I also did this test with another piece of cement, and as you can see the water soaked up it about 1.5 inches. Where the water soaked into the cement, you can see it's visibly darker, but it really does not feel very moist at all. I'm sure this would give off some humidity, but I'm not sure ants would be able to actually drink from it.
 

 
 
At this point, I think I'm going to go with ceramics, which for this particular formicarium should be pretty easy; I'm not sure about my other designs though.

[dspdrew]

I found something interesting on the sponge of the water tank with the layer of Hydrostone in the bottom. This is obviously the same crusty stuff that sweats out of the Hydrostone when its wet. It's something that's crystallizing similar to the way salt does, but I'm just not sure what.
 

 

 

 
 
Anyway, I'm done with Hydrostone for these projects now.
 
Here I cut a piece of an unglazed ceramic tile and epoxied it to the bottom of the container. To fill in around the edges I used cement. Sure it would be nice to have a tile that fits perfectly in the bottom of these, but that is almost impossible to do without destroying the sides of the container. Also, cutting tile to that tolerance is very hard, and time consuming, so I figured this would be the best way to do it.
 

 
The main problem with this is it looks like crap, so I figured maybe I could just try pouring cement in there alone, exactly the same way I was pouring Hydrostone into them. This looks MUCH better and it's smooth and clean. I even found out they make white portland cement, so if I can manage to get a hold of some, that should look even nicer. Another good thing about this is I won't need to modify the containers at all. All I needed now was to test how high the humidity would get in there with a material that doesn't absorb all that well.
 
You can see the water starting to soak into the cement here.
 

 
 
Eventually it soaked all the way in as far as it was going to go, and the humidity was not too bad at all. It was right around 82%, and enough to allow some condensation to form on the sides.
 

 
 
Interestingly, I tested out the one with the tile and cement, and the humidity was only one or two percentage points higher than this, so yeah, this is much better, and I think it's the solution to this problem. Now I just have to test it out on one of my smaller colonies. This might even be better, because the Hydrostone absorbs water so well that it's always soaked, and the ants just make a mess out of all their hoarded substrate; sometimes it even starts growing foreign fungus.

[Gregory2455]

Gypsum crystals! Your hydrostone formicariums will start looking like this cave:

[dspdrew]

Oh duh, that shouldn't have been hard to figure out. Yeah it's obviously gypsum, and that's obviously what's dissolving.

[dspdrew]

So I just thought I would test the humidity in the hydrostone container after moving the colony out of it, and it actually came out to be 81% RH, one percentage point lower than the cement one, so even though it is not all soggy like the Hydrostone, the RH inside is just the same.

[drtrmiller]

I've solved your corrosion problem.  

 

Lose the sponge and stick the reservoir on top.  

 

For additional reinforcement, add 5-10% cement to your Hydrostone mix, by weight.

 

 

It's a blue bottle with the head stuck in the plaster.  

 

If you don't want to use a blue bottle, you can accomplish the same thing by welding two pieces of acrylic that form a 90 degree angle to two, perpendicular inside side walls of a container.  Then, pour your Hydrostone to cover the gap at the bottom.

 

Edited by drtrmiller, February 1 2015 - 4:54 AM.

[dspdrew]

And how is that going to stop the plaster from dissolving?

[drtrmiller]

It works because the resulting precipitate that would previously form on the sponge, and by its absence cause a pinhole, can no longer be displaced to the sponge to form a pinhole.

Edited by drtrmiller, February 1 2015 - 1:07 PM.

[dspdrew]

I'm pretty sure it's forming on the sponge, because it's dissolving into the water. The sponge in my pictures just had Hydrostone on the bottom of the tank. Anything you lay on Hydrostone that is wet, will dissolve the Hydrostone and leave a mark. If it's wet and touching the Hydrostone, it's going to dissolve it. I'm not sure how your bottle is getting water to the Hydrostone without touching it.

[Jonathan21700]

I'm pretty sure it's forming on the sponge, because it's dissolving into the water. The sponge in my pictures just had Hydrostone on the bottom of the tank. Anything you lay on Hydrostone that is wet, will dissolve the Hydrostone and leave a mark. If it's wet and touching the Hydrostone, it's going to dissolve it. I'm not sure how your bottle is getting water to the Hydrostone without touching it.

I have the same problem with plaster. When I water the nest it leaves a white residue on the walls.