DIY rock

[Serra]

I have had my DIY rock soaking for 6 weeks. My tap water is around 8.9 so I can't tell if the pH is acceptable or not. I guess I will have to soak it a few days in RO water and check that. I did water changes every other day...

I am disappointed in the turn out of the shapes. The pieces with holes in the middle broke. I damp cured them for 3 days before moving them to water. I really have only a few usable pieces after 6 weeks of work and wait. :sad2:

 

[Travis L. Stevens]

Sorry to hear that. Hopefully that won't discourage you from trying other batches with various differences.

 

[captbunzo]

I had similar experiences - I think there is something we are missing since Travis' rock is fine. Which of the following did you do:

1. Mix salt & cement, and THEN add water?
2. Mix cementer & water, and THEN add salt?

Please detail more on how you mixed your rock so that we may all learn from your experience.

Thanks!

 

[Travis L. Stevens]

<a href=showthread.php?s=&postid=7900038#post7900038 target=_blank>Originally posted</a> by captbunzo
I had similar experiences - I think there is something we are missing since Travis' rock is fine. Which of the following did you do:

1. Mix salt & cement, and THEN add water?
2. Mix cementer & water, and THEN add salt?

Please detail more on how you mixed your rock so that we may all learn from your experience.

Thanks!

FWIW, I did the first one. I have a theory though. I suck at judging how much water I need. I often get it too wet. So, I have to add cement. I'm guessing by the time I get the consistancy I want, it might be 1:2-1:3 ratio when I'm done.

 

[captbunzo]

I can't try again any time in the next week, due to impending vacation. However, when I can get around to it, I plan to start making some more rock. This time I am going to use the second method above.

 

[Serra]

I mixed the salt and cement then added water. I did the 4 cement to 1 water ratio for one batch then went to about 5/1.

I could have been more careful in the dumping water then rinsing rocks process but after a month I just ran out and changed the water so was less careful. I also find the rock to have many small sharp edges that I see as a potential for wounds.

I don't think I will be making any more. My wrist is bothering me and I need to save it for computer work. I could not stir the batch at this point.

I am also using the wrist excuse for typos, unmade bed and bad hair...

 

[BrianOKC]

I followed the instructions in Travis's DIY thread. The first batch i made was very brittle and was almost hollow with all the salt in the mixture , they would also start to float after a few days of soaking. So i added some crushed oyster shell to the mix this helped 100% and made my rocks much stronger. If i had to guess was probably 3 part salt 1 part crushed oyster shell and 2 part portland cement type 1. The reason i added 2 parts of cement was with only 1 part cement was very hard to shape the rocks into caves and such. I also used PVC pipe of different sizes and wrapped cement around the pipe after a few days soaking u can pull the PVC right out of the cement and u have a perfect tunnel the whole way down the rock , this i recommend to everyone u just go to the hardware store buy a few different size pipes and cut them to what ever length u want and make sure you have a good coat of cement all around the pipe I'd say prolly 1" to 1 1/2" and leave a few inches sticking out on each side. Then let the pipe soak for a few days and pull the PVC out of the rock most of the pipes came right out there was a few i had to use a pair of pliers to get them to come out but wasn't too tuff.

 

[chris4693]

Here is what I have always used and it works great. Cost a little more and you can't mess up the mix if you use equal parts everytime.

CaribSea Special Reef sand (I believe, anyway it looks basically like really small agronite rocks, 2 to 5 mm in size.
Southdown Sand
#3 Portland

The Mix:
5 parts CaribSea
1.5 parts sand
1.5 parts portland

I mix it somewhat dry, just to when I grip it in my hand it holds its shape. Personally I wouldn't worry about the salt, every time I have made rocks I have been able to turn on the water hose and it just runs right through the rock. Most of the peices that I made and didn't like I broke up and used them for frags. I had to have a hammer to break it up.

On a side note I used straight portland, not cement, most cement has gravel and sand already mixed into it with the portland. Since I was providing my own sand and rock I just used portland.

With this method you can make your own rock for less then $1 per pound, depending on what kind of a deal you get on the CaribSea.

 

[captbunzo]

I'd say that this would be a great case to use Pavestone Pulverized Limestone and save some money... (That is, if you are going to use sand)

 

[BrianOKC]

Chris as far as i know Portland cement never comes with sand/gravel. Now if were talking about concrete then yes it has lots of different things added to cement to make it concrete and give it strength.

 

[captbunzo]

He meant to say concrete...