The Ultimate DIY Rocks!

Plopped it in the trash cans I bought and covered it with salt.
102_0457.jpg

102_0456.jpg

Packed on the salt so it would stick well.
102_0458.jpg


Recipe I used (approx):

1 Part Cement
1 Part Sand
2 Parts Salt

I took a small piece out and started soaking it in some warm water and it's very light and very porous stuff. Kind of ugly looking but for less than $.50 a pound I think I can live.


I'm letting it dry as we speak and will have some more pics in a couple days. Happy DIYing everyone! :D
 
Hey xJake - Welcome to the thread :wavehand:

Great pics! You'll have to keep us posted. Might leave it alone for a week or two since that is a really lean mix you are using - this will give it more time to cure out and gain strength.

Let us know how it goes :)
 
I pulled the rocks out of the salt (they were relatively hard on the outside) and put them in an empty trash can to fully cure. I mixed up some more pieces and made them a lot larger and more bulky (less shelf-like). I'll have some pics up later of the rock I pulled out. My camera is acting up and won't turn on for some reason, and I just put in new batteries too.

Anyway, thanks for the welcome :D . I'll be sure to keep you guys updated on how it turns out. From the small piece I pulled out and started curing it looks like it's gonna turn out fairly well. It's a bit crumbly on the outer surface but I think its just the leftover cement that covered some of the salt crystals that dissolved.
 
Ok, so I pulled the rocks out last night and hosed off all the exterior salt to show you guys the great texture that the salt made. They've been baking in the sun all day and they've hardened up a lot. Ok, time for some pics (soup can for scale):
102_0459.jpg

102_0460.jpg

102_0461.jpg

102_0462.jpg

102_0463.jpg
 
Oh, I also forgot to mention that I made another batch and this time I used 3 parts salt to see how it would turn out.
 
Thanks for the pic's, Travis :) Starting to look really good.

xJake. Looking good. :)
You should really avoid the drying out at this stage though. Water is a vital component of cement hydration, which in most instances is a 7-28 day process. Hydration, if done improperly, will make weak rock that will eventually disintegrate, and probably sooner than later. Just because it seems to be doing just fine right now, the salt, coupled with allowing the moisture to evaporate, are "two strikes" against the cement.

Salt rock is really porous, but we have been getting reports of this salt rock turning to gravel - just so you know.
And the more salt you add, the weaker the resulting cement comes out...
You can always google for cement and salt or salt immersion, looking for the basic reactions and information. There is a lot of information about it and some of it is quite fascinating.

Keep up the good work and keep us posted :)
 
<a href=showthread.php?s=&postid=12634719#post12634719 target=_blank>Originally posted</a> by Insane Reefer
Thanks for the pic's, Travis :) Starting to look really good.

xJake. Looking good. :)
You should really avoid the drying out at this stage though. Water is a vital component of cement hydration, which in most instances is a 7-28 day process. Hydration, if done improperly, will make weak rock that will eventually disintegrate, and probably sooner than later. Just because it seems to be doing just fine right now, the salt, coupled with allowing the moisture to evaporate, are "two strikes" against the cement.

Salt rock is really porous, but we have been getting reports of this salt rock turning to gravel - just so you know.
And the more salt you add, the weaker the resulting cement comes out...
You can always google for cement and salt or salt immersion, looking for the basic reactions and information. There is a lot of information about it and some of it is quite fascinating.

Keep up the good work and keep us posted :)

I'll keep that in mind from now on and I'll be sure to keep you posted on what happens. I don't think I did too much damage as the rock stayed fairly damp most of the day after being hosed off. Good thing I didn't make too large of a batch with the 3 part salt content. The pictured rock is now soaking in 2- 32gallon trash bins with a constant water change running. I'm making another batch tomorrow and I'll post some more pics. Thanks for the reply! :D
 
Has anyone tried Calcium pills as a filler? They would dissolve over time AND release calcium? A quick bath in vinegar would take off the outside ones...Any ideas?
 
I suppose it depends on what kind of calcium pellets you used. If you used calcium chloride it would create an exothermic reaction within the rock which would probably cause the rock to crumble from the interior. If you've ever mixed it for Randy's 2-part then you know what I'm referring too. I can't think of any other calcium salt that would create a good looking texture on the rock, would be safe for a reef tank, AND is relatively cheap. Also, releasing calcium isn't necessarily a good thing.
 
Last edited:
Hey Eznet :)
I have tried gelatin cap calcium, and that didn't go so well - the gelatin caps get weird and after like 2 and a half months, there was still gel "stuff" and lumps of calcium. Possibly regular non gel capsule type calcium would have a better chance.
However, it might be challenging to figure out the release rate on something like that. The cement will sort of "fuse" the pills to the rock, so waiting to leech it out could take a long time, and unless you try it in a controlled test, you'd have no idea how much calcium would be leeching at once...
 
The salt wont dissolve... I am using water softening salt and some salt crystals ranging in size from 1/8" to 1". Even the smallest salt crystals just below the surface wont dissolve. I have had one rock soaking for a month and when i crack it in half still big salt everywhere. I am not making huge thick Rocks either... Has anyone encountered this?

I spritz it with water every other day and cover it in a bag to hold moisture in for 2 weeks then submerge.

By the way Excellent thread!!! i have been scouring the net for threads on making DIY rock and this is by far the best for tips and tricks. Thanks.
 
Hey Kronk, Welcome to the thread :wave:

It isn't uncommon if the water is cool or cold and/or the cement mud is dense. The more sand or aggregate that is used, the more porous the rock tends to be...

Add some heat and water movement and it will go faster - just don't boil the rock.

Let us know how it goes.
:)
 
I have still been experimenting with my mix. I want to build a large one piece structure to fill up a 65g. I have built a PVC structure with the shape i want and have tried several methods to get it to hold around the PVC such as saran wrap, bubble wrap, cheese cloth a combination of all the above.

The best way i have come up with so far is by creating a mold in extruded polystyrene and making multiple pieces then cementing them all together later.

Below is a rock i used to test out the casting method... still way to dense for my liking i am going to use a ton of softening salt with the next test batches. I am still having trouble getting the salt to melt...

ROCK001Large.jpg


Cheers,
Ken
 
Back
Top