The Ultimate DIY Rocks!

[sunkool]

<a href=showthread.php?s=&postid=10201101#post10201101 target=_blank>Originally posted</a> by mr.wilson
I would use a quick setting hydraulic cement and save yourself all that hassle of moving the rock around. I let it sit for a few days then fill it up. The same water is in there years later.

After a few weeks, I use a toothbrush to remove the calcium salts that migrates to the surface of the cement. The PH will be back to 8.2-8.4 after a few days of soaking in saltwater.

The cement will bond well to the PVC pipes if you use only 25% aggregate.

Mr Willson
If hydraulic cement is non porous why use it? Yes it may have a low ph in 3 days but still takes 28 days to fully harden. If it still takes 28 days it might as well be porous. No?

Compressive Strength (ASTM C-109*)
1 DAY - 4,200 psi
3 DAYS - 4,300 psi
7 DAYS - 4,500 psi
28 DAYS -6,100 psi

Description
Unitex HYDRAULIC CEMENT is a blend of hydraulic cement and admixtures used for plugging and stopping water or fluid leaks in concrete structures and masonry walls.


When mixed to a thick consistency and hand formed, HYDRAULIC CEMENT will set in 3-5 minutes to seal out water for the life of the structure. HYDRAULIC CEMENT is a non-corrosive, non-rusting and non-shrink material.

 

[Insane Reefer]

Mr Wilson, as he has said, mainly uses the quick set cements to form backwalls and to bind real LR together - as far as I know, he has never used it to make rocks for filtration.
For these purposes, it would work great.
And while it may take 28 days to reach full strength, close to 75% of its strength is reached in one day, and pH swiftly stabilizes - in a few days or a week, instead of 3+ weeks of water changes (which could be hard in the systems he is working with).
Not for every project, but it does have it's uses.

Mr Wilson can add more, I'm sure

 

[reefnewbie54321]

I am all finished with my rocks but after seeing all the new methods of doing it I'm actually gunna start all over. I remebered this thread when it first started so I used the original recipe of just salt and cement. After seeing all the new techniques and arregrete I want to make new ones.

Can any one tell me were to get white portland?
I checked at Lowes and they didnt have it but I havnt gone to Home Depot yet but I dont ever remeber seeing it there before.

Insane Reefer,
what was the brand of perlite used that you bought at Walmart and did you like the perlite better or should I just stick to Crushed Coral?

And last what sand would you reccomend, does any play sand work or is there a specific brand/type that works better then others

 

[Insane Reefer]

Hi Newbie,
Use the other rock in your sump - or take it to your LFS and trade it in for something you want - don't let your time, effort and materials go to waste.

White portland is difficult to find; the big box stores do no carry it as there isn't enough call for it. You will find it at a masonry supply, if you can find it at all - the place the pro's go to get their stuff, and even then, there is no guarantee. I know of two brands of white, Federal and Lehigh and usually they run right around $20 a bag. You might also try a local statuary place, or a place that makes in-ground pools - they often use the white and maybe you can talk them into selling you a bag or tell you were to go to get it. In Boston, there has to be a lot of repair on all those historic brick buildings, so there should be someplace to get it.

Sand is pretty much up to you. Most of what is offered in the states is going to be clean and ok to use; it then becomes a matter of taste, preference and price. I've been playing with the sand blasting sand for my last couple of batches. One thing I've noticed about the limestone sands is they are really caustic coming out of the bag. I feel a "burn" from the wet limestone sand that makes me wonder how it might effect pH, so I'm doing some comparisons. For the next few batches of Jiffy Rock I am trying with the blaster sand, wondering if that will effect the pH in any way. With white cement, the sand blaster sand almost disappears. Usually, sand is fairly obvious on the outside of the rocks, if you casted in sand, but this stuff is very non-obtrusive visually. I'm pleased with the results so far, and you can generally find it in 90lbs bags for $7 or $8. "Toys R Us" sand is glassy, and shiny, but fairly small grained - it sells for around $5 a 50.
And finally, I am using the Schultz brand perlite that can be found at Walmart in the garden section - Green bag, actually found it inside with the house plants. I've seen this stuff at almost any place that carries potting soil, grocery stores included. I am liking the Perlcrete so far, and learning how to work with it, but most that I've made is only a few days old, and all have been play batches, so I really can't say much at this point.
Should you use it? No, not at this point, unless you have a tank you are willing to do a few test pieces in. We just don't know enough about the perlite yet to know that it is safe in our precious reefs.

Good luck with it, post some pictures and never hesitate to ask if you have a problem, or more questions.

 

[blakeoe]

hey guys! I followed this thread religiously a few months back and made 4 batches totaling about 300lbs of rock. unfortunately i havent checked the thread in months. the biggest thing that turned me off about this is the soaking time. did you guys find a way to shorten the soaking ("curing") time?

 

[Insane Reefer]

Still working on it Blake
Keep in mind that the MMLR hobby hasn't changed in 10-15 years; they way they made it then is the way we make it now. The first and only new contribution to the field has been solar salt.

Me and the lab monkeys have been experimenting with what basically is "steam curing", and it shows a lot of promise, but I still have a ways to go before I can comfortably recommend this as a good alternative method. I personally have gotten consistent results of pH in the 9 range with rock that is a week old or less.

However, Jiffy Rock will never be something that just anyone can do - batches are limited to what you can fit in your stove, and each batch must bake for 4-6 hours in a very moist stove - there is the potential that one's stove could become damaged by repeated bakes, but I have done over 10 bakes now and my stove is just fine.

So other than quick set cements, or steam curing, it is all the same for now. But a lot of people are thinking about it - change comes with new ideas. For any rock we make, carbonation is important, and so a lot of thought is being given to this. Carbonation has become my new mantra. When all is said and done, it is this mechanism that makes our rock safest to use - when carbonation occurs, the high(er) pH components are transmuted to calcium carbonate - the philosophers stone, if you will, of MMLR - the more carbonation, the lower the pH drops.
IMO, and from what I've been able to determine through google and library research...

So we are trying to determine ways of making this happen, that will apply to most rock and anyone can do. We have found a few references to Sodium Bicarbonate, and they claim that bicarbonate in the water causes a quick carbonation of the rock - one guy claims in two weeks, though he also says that if he didn't buffer his system so heavily, he wouldn't be able to use it (did anyone else catch that?) safely, so I think that his testament might be worthless as it pertains to us.

We discuss it in the last few pages, before my "Super Long Post"; a few of us are adding BS to our kure baths to see if anything exciting happens.

It looks like Co2 is the best candidate for carbonation, however it is usually done at pressure, which most of us can't do, and adding to to water makes carbonic acid, and a cement engineer told us that that would simply strip the carbonated layers and create a vicious cycle, leaving us with rock with a high pH. Rain actually seems to be the best delivery system for Co2, from what I can find, but it could take months for that much rain to fall, and holding it in bins to use isn't the same - it needs to be fresh rain, with lots of readily available Co2 to do much good
Wonder if a sprinkler would do the same thing???
Maybe Mr Wilson, Travis or someone else how has a fairly good grasp of chemistry can answer that. Wouldn't it be great if you could just place your rock in and around your garden or lawn and just turn the sprinkler on for an hour or two a day, once or twice a day, and get your stuff watered and kure your rock at the same time?
Just a thought.

 

[blakeoe]

Thank you insane! i certainly look forward to the day when i can make a rock for my tank and use it the next day or even next week. i thing tru rockscape customization will be achieved!! I have a ton of great ideas for rockscape however most require allot of trial and error and with each batch taking months it's impossible to achieve. One thing that i always questioned is how do zoos and aquariums and things do their cement tanks and habitats? you always see cement ponds at alligator farms with fish in them and cement tanks and "reef balls" at aquariums and so on.. how do they do it?

 

[Neptune777]

<a href=showthread.php?s=&postid=10233815#post10233815 target=_blank>Originally posted</a> by reefnewbie54321
I am all finished with my rocks but after seeing all the new methods of doing it I'm actually gunna start all over. I remebered this thread when it first started so I used the original recipe of just salt and cement. After seeing all the new techniques and arregrete I want to make new ones.

Can any one tell me were to get white portland?
I checked at Lowes and they didnt have it but I havnt gone to Home Depot yet but I dont ever remeber seeing it there before.

Insane Reefer,
what was the brand of perlite used that you bought at Walmart and did you like the perlite better or should I just stick to Crushed Coral?

And last what sand would you reccomend, does any play sand work or is there a specific brand/type that works better then others

Did your Lowes or Home Depot carry Quikwall? It is white faster curing cement with fiberglass fibers in it (don't worry it's reef safe!). I'm lucky in that my Lowes and Home deport carry it locally......it's good stuff.

 

[Insane Reefer]

<a href=showthread.php?s=&postid=10235159#post10235159 target=_blank>Originally posted</a> by Insane Reefer
Rain actually seems to be the best delivery system for Co2 - it needs to be fresh rain, with lots of readily available Co2 to do much good
Wonder if a sprinkler would do the same thing???

Ok. Rain has so much Co2 because it falls through the atmosphere and "picks" it up. A sprinkler would not pick up enough Co2 to make any difference. However, a rain barrel would hold the Co2 for quite a while (unlike my first thought), so might be worth looking into...

 

[Insane Reefer]

<a href=showthread.php?s=&postid=10235902#post10235902 target=_blank>Originally posted</a> by blakeoe
One thing that i always questioned is how do zoos and aquariums and things do their cement tanks and habitats? you always see cement ponds at alligator farms with fish in them and cement tanks and "reef balls" at aquariums and so on.. how do they do it?

You have to remember that aquariums and zoos are so completely out of our league.
Many use pump systems that simply exchange water with the ocean. Many have huge processing facilities. They aren't using hobbyist equipment.

So, often their cement work isn't required to provide filtration - it is simply pretty and a framework for the display. From what I understand, many institutes use "shotcrete", or quick setting cements.

 

[Insane Reefer]

<a href=showthread.php?s=&postid=10236226#post10236226 target=_blank>Originally posted</a> by Neptune777
Did your Lowes or Home Depot carry Quikwall? It is white faster curing cement with fiberglass fibers in it (don't worry it's reef safe!). I'm lucky in that my Lowes and Home deport carry it locally......it's good stuff.

Hmmm...
:mixed:

 

[mr.wilson]

<a href=showthread.php?s=&postid=10232344#post10232344 target=_blank>Originally posted</a> by sunkool
Mr Willson
If hydraulic cement is non porous why use it? Yes it may have a low ph in 3 days but still takes 28 days to fully harden. If it still takes 28 days it might as well be porous. No?

Compressive Strength (ASTM C-109*)
1 DAY - 4,200 psi
3 DAYS - 4,300 psi
7 DAYS - 4,500 psi
28 DAYS -6,100 psi

Description
Unitex HYDRAULIC CEMENT is a blend of hydraulic cement and admixtures used for plugging and stopping water or fluid leaks in concrete structures and masonry walls.


When mixed to a thick consistency and hand formed, HYDRAULIC CEMENT will set in 3-5 minutes to seal out water for the life of the structure. HYDRAULIC CEMENT is a non-corrosive, non-rusting and non-shrink material.

IR pretty much said it all. For all intent and purpose, it's fully hardened in five minutes. The additional 25% strength that slowly comes over the next month is redundant.

I've been using water-stop cement only out of caution. My experiments have been on expensive tanks, so I can't try something new each time. Right now I'm stuck on, "if it ain't broke, don't fix it". I'm sure there's a better product out there. More work time would be nice.

The water-proof stuff I've been using has more than enough surface area for aerobic bacteria. It should also be able to support sufficient colonies of denitrifying bacteria (anaerobic). I'm using live rock for the rock work, so it's a moot point.

I covered some PVC parts with a quick setting (PH stabilized) porous cement, that has a longer work time (20 minutes vs. 2-5 minutes). I never checked the PH as the pieces were relatively small, and the tanks were big. This is the Bomix stuff I mentioned earlier (quick patch?).

The faux reef walls need to bond well to glass or acrylic, so I'm more concerned with bonding strength and shrinkage, than denitrifying capabilities. The walls I've done are about 2" thick, and they allow water to soak through to the glass/acrylic. This may not hold true with a 6" dia. rock. The pores of hydraulic cement are smaller, so they offer more surface area than void space. This means a more conducive environment for denitrifiers.

The main benefit of portland-based mixes is the cheap cost.

 

[Rhodophyta]

<a href=showthread.php?s=&postid=10235902#post10235902 target=_blank>Originally posted</a> by blakeoe
Thank you insane! i certainly look forward to the day when i can make a rock for my tank and use it the next day or even next week. i thing tru rockscape customization will be achieved!! I have a ton of great ideas for rockscape however most require allot of trial and error and with each batch taking months it's impossible to achieve. One thing that i always questioned is how do zoos and aquariums and things do their cement tanks and habitats? you always see cement ponds at alligator farms with fish in them and cement tanks and "reef balls" at aquariums and so on.. how do they do it?

Two comments here. There already is instant porous live rock. You substitute a much smaller proportion of resin for the portland cement and use a different molding method since the wet product sticks to everything except wax paper that you line the mold shapes with.

As to "how do they do it", I have a very old pre-electric gardening book that goes into detail about preparing cement ponds for use. These old timers didn't dwell on how their methods worked. I think though that it's because they were more organic, using things like tree leaves, peat moss, manure in situations where we would go with chemicals. This organic approach gives the aerobic (good guy) bacteria an earlier opportunity to seal off the cement and create a pH boundary layer. Our good guy bacteria have to wait until we are finished playing with chemicals to take over and do it right.

 

[Insane Reefer]

<a href=showthread.php?s=&postid=10238468#post10238468 target=_blank>Originally posted</a> by Rhodophyta
Two comments here. There already is instant porous live rock. You substitute a much smaller proportion of resin for the portland cement and use a different molding method since the wet product sticks to everything except wax paper that you line the mold shapes with.

Could you go into more detail Rhody?
You can't wave something like that in front of us and leave it unfinished, lol.
:wavehand:

 

[Insane Reefer]

And Rhody, since you are active (here), what do you know about Aluminum Powder? I found reference to it being used to produce hydrogen bubbles within the matrix. I think it would be safe for the reef. Do you think this is something that could be added to quick set cements to add porosity?

 

[Rhodophyta]

<a href=showthread.php?s=&postid=10238477#post10238477 target=_blank>Originally posted</a> by Insane Reefer
Could you go into more detail Rhody?
You can't wave something like that in front of us and leave it unfinished, lol.
:wavehand:

It is already posted way back in the thread, before the salting, basting, cooking ideas. Basically you use only enough resin to dampen the other ingredients, less than you will want to add, but if you add too much, the lower parts of the new rock will be shiney since the excess resin will sink to the bottom during the short curing time. You can only create as much texture as will be transferred by wax paper so you want the mix dry to keep the texture of the sand or gravel. To create complex shapes, you have to make several pieces that will stack and then tack them together with resin or count on gravity. Great for coral tables, backgrounds, caves, but I don't know how you could ever make the great branching pieces I've seen pics of here. OTOH, not many seem to be experimenting with it.

 

[Rhodophyta]

<a href=showthread.php?s=&postid=10238495#post10238495 target=_blank>Originally posted</a> by Insane Reefer
And Rhody, since you are active (here), what do you know about Aluminum Powder? I found reference to it being used to produce hydrogen bubbles within the matrix. I think it would be safe for the reef. Do you think this is something that could be added to quick set cements to add porosity?

I know it is used to create super light concretes, some of which can float. I suspect if the bubbles connected to create a porous network that the whole thing would collapse like a failed souffle. But them who would imagine a souffle if they'd never seen one? Maybe combining the quickset curing time with the hydrogen bubbles would let you use more, and "freeze" the souffle just before it burst. Sounds purely experimental. Speaking of weird concretes, I've seen literature about new porous cement sidewalks, driveways, and parking lots that require less runoff management because rain soaks through instead of running off in streams. They had some samples at the lumberyard last year. I wonder if it's online somewhere, but I think the process was proprietary.

 

[mr.wilson]

If you have time to experiment or research the subject, calcium hydroxide, known as hydrated lime or quick lime in the construction trade, will speed the setting & curing time of cement. It's the ingredient that causes cement to heat when it sets. You can also make rock with it, as a substitute for portland.

I have an old house (pre-portland) with hydrated lime mortar. They would have made it on site out of the dolostone (limestone & dolomite based rock) that we have here. Crushed dolostone would have been used for the aggregate as well. I have no idea what the PH shift is like as it cures, but it's worth looking into because it's a quicker reaction.

The interior of my home still has some lime plaster with horse & cow hair for aggregate. Back in the day, they used blood on the final coat to slow the curing process to control shrinkage cracks. They used potassium sulphate (salt) to speed the setting & curing time.

Perhaps potassium sulphate would be a more appropriate salt for our purpose. Do a search on hydrated lime, quick lime or limestone mortar and you will see the properties.

http://www.restorationtrades.com/articles/art30.shtml

 

[Neptune777]

<a href=showthread.php?s=&postid=10063879#post10063879 target=_blank>Originally posted</a> by Neptune777
Has anyone tried using the clear epoxy (same kind used to make the fake deep sand beds) to make DIY rocks? Just mix in enough to make the crushed shells or crushed coral stick and then mold it into shape over a trough of sand? No curing needed and in theory the epoxy should be very strong and the "rocks" porous if you use the epoxy in the correct ratio...

If you think about it the cement is used just to glue or hold the small rocks etc. together....so why not substitute portland cement with epoxy cement.....then no cure time is needed?

I forgot that I posted this a while back....has anyone experimented with it to determine the proper ratios of epoxy and aggregates?

 

[Neptune777]

<a href=showthread.php?s=&postid=10064164#post10064164 target=_blank>Originally posted</a> by Rhodophyta
Yes, one of the C-SEA members introduced the idea a few years ago here and it seems to have caught on. He used an epoxy from Home Depot and found you should use much less than seems enough. If you use too much it will settle to the bottom creating a shiny spot. It will stick to everything -- except wax paper-- so you have to double coat the form, and everything that might get affected, with wax paper. I don't know what would happen if you mixed salt in to create voids.

Do you happen to know which epoxy they used?