The Ultimate DIY Rocks!

[2004jeepoutlander]

I love to make "acro table" rocks i think they will sell very well..

[Insane Reefer]

How about a few pictures Jeep?
We love pictures

[mmm55645]

I joined some of my rocks together with water stop cement. In about a week I am going to put them into my tank.
I am starting a new tank. Does it make any difference if the rocks are in the cycle at the beginning or after the tank is cycled? The rocks should go in before the cycle starts, correct?
Anyone use one of the fast curing cements to join rocks together and if so do you use the cement and an aggregate or just the cement?
I will post a few pics of my finsihed rocks soon.

[Insane Reefer]

It will take a while for your rock to become "live", so yes, start it along with the tank. Seeding with sand from a trusted source will get the ball rolling, or just order up a GARF Grunge pack - I hear those are pretty good. Keep the load light for the first 6-9 months, and you will have nice LR.

[airinhere]

Insane reefer, you have PM.
And I am looking for Mr. Wilson and Travis also. So they should have PM.

[Insane Reefer]

Gotcha, Air'

[Insane Reefer]

Ok, only a few more pages until the split, so time for the "Super Long Post"


v6.5

Hey All,
I'm going to post my favorite tips and links every so often so new people can find it all pretty easy. It is a summation of the most commonly asked questions and things I have picked up through making my batches. Some I’ve gleaned from this thread, others I’ve learned from past mistakes and experiments. I've been making DIY man-made rock or aragocrete off and on for close to 8 years. Lately, I have even made some money on my rocks.


This does not contain any information on "Jiffy Rock", the new method I am working on to produce rock in under a week or 10 days. This only pertains to traditionally cured rock methods.

I thought I’d pass this info on – maybe save someone some frustration or spark a new idea.

I will continue to refine and update this post as more info is added, and repost every so often.



First, good info can be found at these two places - I think everyone who wants to make rock should read these in full. One of the articles gets pretty heavy handed with the science/chemistry aspect, the other babbles on tangents once in a while, but both are worth the read, IMO.
ARAGOCRETE RESEARCH BY TRACY GRAY
Reef Propagation Project:

And this link is for Cement Colorant . They sell it in small amounts in rainbow colors and are very cheap.

List of Appropriate Aggregates
Sand - caribbean/aragonite is “best”, but very hard to find at a reasonable price. Any “clean” sand will work – look for darker grains which could indicate heavy metals. “Toys R Us” carries a play sand that a lot of folks use and report no trouble with. Limestone sand/Pulverized Limestone has gotten good results as a DSB, so should also work and can be found at some Big Box Stores like Home Despot. Sand Blasting sand can also be used and is sugar fine, look for Unimin Brand, or any that says it can be used for filtration – this will be 99% pure Industrial Quartz. Whatever you choose, keep in mind that the smaller the grain size, the less obvious it is in and on the rock.
Crushed Coral - AKA "CC". Makes nice, realistic rock, but it is expensive.
Crushed Oyster Shell - AKA "OS". Any shell will work, but OS is very cheap at feed stores.
Calcium Carbonate - This stuff comes in a range of textures and grain size – from sand to gravel like CC. Most feed stores will carry it in some form, and for less then $4/ #50.
Dolomite – Same as Calcium Carbonate, just another name (and slight chemical variation) and is just fine to use.
Perlite – has a pore structure similar to CC, but much, much cheaper – great for making light weight rock. It is basically inert, puffed glass.
Salt - Many thanks to Travis Stevens for figuring this out! The salt of choice is "Solar Salt Crystals", typically found as a Water Softener Salt. 99% pure salt. Get the coarsest crystals you can find. Solar Cube can be used, but is sort of chunky - makes nice holes though. Boiling the "cubes" rounds off the edges and makes nicer holes. Solar Pellets can also be used, same as Cubes. Look at your grocery stores or wally-worlds if your local hardware doesn't have what you want.


Rock Recipes
Ingredients are measured by volume, not weight!

Travis’ Original Recipe: 4:1 or 3:1 / Salt:Cement
Improved? Recipe: 3:1 or 2:1 / Salt:Cement
Ol' Skool Recipe: 1 to 1.5 : 2 :1 / Cement:CC&OS(mixed – or use perlite):Sand
Ol' Skool+ Recipe: 1: 1 to 1.5 : 1.5 :1 / Salt:Cement:CC&OS(mixed – or use perlite):Sand



Mix dry ingredients together first, excepting salt - add tiny amounts of water while vigorously mixing the slurry. Slurry should be “dry” and crumbly, not wet and squishy – there is a fine line between the two. A wet mix will not have as many natural voids in it, be less porous, and will also bind to the salt, making salt release more difficult. Once you have reached a slightly wetter mix then you think you need, lightly toss the salt into the mixture, and then mix it very quickly – the more salt that leeches off the crystals, the more deleterious the results can be. Be aware that a dry mix may give the illusion for the first week of being more brittle, but after a week or so, it toughens up and is nice and hard. After you make your rocks, they need to be kept moist and warm for a week or two to achieve the best hydration possible – though many do take their rock out and start salt release or kuring in 3 days or so, and haven’t reported any bad side effects. However, new info is starting to show that to put your cement in water before the 2 or three week range is needless – water doesn’t really start doing its job until the hydration is coming to a halt, so leave it sitting and save water and effort. Plastic bags, wet newspaper, wet casting materials and the like will help seal in moisture. If you think the rock might dry too quickly, mist it with a bottle or hose every so often.

Molding Material
Really, pretty much anything that is dry and crumbly/powdery will work. I've even used stuffing bread crumbles, but that draws bugs while it dries.

Soil
Salt
Sand
Clay

A certain portion of the molding material will remain on the rocks - this can usually be removed with a short acid bath, followed by a good scrubbing with a plastic or fine wire, bristle brush.

If you use Rubbermaid or Tupperware, you can reuse molding material over and over again. Line cardboard boxes with plastic to prevent moisture leak and wall collapse.

DO NOT Wet Salt, if it is used as a mold material - this means when working with salt, do not add water to the casting box as you would or might with say clay or sand.

----------------------------------------------------------------
Now, I will list my tips and tricks, in no particular order. Many will seem stupid or like common sense, but you don’t know about some people’s kids, lol…

Tips and tricks

1. Wear gloves when making rock. If possible, don’t let the cement get on your skin, especially the dry powder. If possible, wear a painter’s mask when measuring and mixing dry cement; this stuff can really burn the inside of your nose.
2. Setup your work area in advance; cover surfaces with plastic or old sheets if needed (like in your kitchen or living room). Fill casting containers with whatever mold material you are using, or have it standing by within easy reach. Give yourself walkways if you are making a lot of rock – nothing sucks as much as trying to create enough work space after the fact.
3. Think about the weather for not only the day you cast, but the next few days as well, if you plan on doing this outside. Rain can make a mess of things…
4. Use Portland Type I, II (I/II) or III – these are known to be safe for use and make rock with proper porosity.
5. Mix all aggregates excepting salt into the cement before adding water. Add salt after you have reached the right wet consistency, and mix it in lightly – the less salt is leeched off the grains of salt, the stronger your final rocks will be. Water softener salt of the type “Solar Salt Crystals” works wonderfully (Thank you Travis Stevens!).
6. I prefer to use crushed coral and sand in my rocks for long term strength, plus salt to add porosity. The aggregates also give realistic details to the rock. My preferred recipe is 1.5 part cement + 1.5 part sand + 1 part crushed coral/shell mix + 1 part salt, but this is expensive to make. You can also use a mix of 1-1.5 cement + 1-2 crushed oyster shells + 1-2 salt.
Mainly, a 1 part cement to 3-4 parts “other” is acceptable, whatever you want to mix together is up to you and you should be ok if you follow the 1:3-4 part rule.
7. Work in layers for added dimension. If you lay a layer of molding stuff in your container, make a few divots in this molding layer first, and add cement to these first to make lumps on the bottom, you can avoid flat bottomed rocks. Now lay the main part of your rock, adding molding material as needed.
8. You can make neat “cliff-face” striations if you take a handful of salt, and lay it just along the top edge of wet cement, forming a narrow line of salt along the edge, laying a thin layer of cement over the salt, and repeating this to form, on the outer edge of your rock, a sort of cliff that looks to be cut by water action.
9. Anything cast thinner than an inch is likely to break, unless you are very careful with it.
10. Find a nice bit of stainless steel or aluminum wire – 2mm or so in width, and bend a handle for one end (remember you will probably be wearing gloves, so bend accordingly). As you cast your rock, use this wire to poke Lots of little tunnels all through the rock – all the way through if you can; this will make the rocks extra porous, and give bug life lots of places to hide and propagate in-tank, as well as allowing more water to move through the rock. Alternatively, you can cast the piece, and then poke as much of it as you can – though this way tends to look a bit contrived. I like the first way better.
11. Once your rock has cured and it has been curing for about a week and if you made it mixed with stuff like crushed coral or shells, mix up a weak acid mix and scrub the outside of your rocks with a stiff bristle brush. Be sure to take proper precautions when working with acid – not only from burns, but from fumes as well!!! If you only made your rock with salt and cement, ignore the acid wash, as your rocks might dissolve, but still give them a vigorous scrubbing - this will loosen the weakest stuff and get rid of it without shedding it all over your tank. If you have shells or coral, this can make the surface even more porous, and clean cement films from shells and the like that might be on the surface. I use a mixture of 1/2c muriatic acid added to 2c water.
12. You can make “lock together” pieces by wrapping a bit of PVC in something like tissue paper or plastic wrap, sticking it in the wet cement of “part a”, and then laying plastic wrap over and around the fresh cement/PVC, and then cast “part b”, making sure to get a good fit around the PVC join. I find this works, but I personally have an easier time if I cast “part a” with PVC set into it, let it cure, then wrap it well with whatever, and cast “part b”, and I can cast really large pieces this way.
13. “Cement Paint”. You can make up a slurry of cement and sand, say 1 part cement to 2 or 3 parts sand, made fairly thin and fairly wet and sloppy, and use it to decorate rock with “coralline algae”. I use white Portland, but I don’t see why white grout or mortar wouldn’t work as well. You can use cement colorants to color the cement any shade you desire. Working with a paintbrush, you can easily replicate the swirling patterns of coralline. I’ve also used this mix to paint/dry brush grey Portland rocks to white.
14. Branching rock/Coral skeletons. Pick PVC pipe a bit thinner than what you want your final piece to be. Cut into appropriate lengths, cutting one end flat and the other at an angle. Drill plenty of holes in the PVC to help the cement stick on. Drill extra holes on the very end that will allow you to tie the pieces onto the “main branch” with zip ties. You can bend PVC into believable shapes using heat from either a propane torch or a heat gun, and a couple of pairs of pliers (use appropriate precautions). After you have your PVC framework, mix a thicker blend of Cement Paint (less water, more cement) and paint/dip the skeleton, covering completely. I recommend hanging to dry, and dipping several times, using a paintbrush to smooth it out and prevent weird drips. When done coating, tie a grocery bag around the hanging piece to preserve moisture and allow to cure 48 hours or more.
15. Think about how corals come to you, as frags and whole colonies, and think about how hard it can be to attach these in your typical rock pile. Flatter surfaces and shallow bowls in larger rock shapes can make latter placement easier.
16. You can make rock “shells” if you want to avoid the rock pile look altogether and these are only limited to your imagination and size constraints. You can stuff the cavity in the back of this hollow construction with cheap $1.99/lbs rock, or whatever you want. I DO NOT recommend making these with the cement and salt only recipe! Make a form of some sort (use your imagination), put it in a box that will fit into your tank (making a rock too big for the target tank blows), and secure it to one side, or more (for multi-part casts) with duct tape. Line the rest of the box with plastic. I made my form from plastic grocery bags stuffed into a garbage bag, with a little air added, and taped that into the target box. Slowly build the shell wall (adding details as you wish), filling the box with salt/molding material, until you have the form covered with a fairly uniform covering of cement. LEAVE ALONE FOR A WEEK! Cover with plastic if you can. See my gallery for pictures of the “”Reef Face” or “Nessy”.
17. Frag Plugs. If you have extra cement at the end of the day, make frag plugs by using a mini muffin pan, and filling with ½in. of cement. Spray the pan with cooking spray for easier release. These can be put in a mesh bag and cured in the toilet tank.
18. Hate scraping the back wall of your tank? You can make thin, wall covering sheets, that can be glued with silicone to the back wall of your tank. Alternatively you could make shelves along those lines. I find casting on a sheet of glass covered in plastic works best for this. Also marking out the actual measurements of the back wall onto the glass helps to avoid sizing issues. I DO NOT recommend using the salt and cement only recipes for this application, nor the use of any salt at all! I also mix this just a little wetter than I normally use. Once you are setup, just drool the cement onto the covered glass. I tried doing large sheets, but these mostly were too weak to hold up and heavy. I find making smaller pieces (12inX12in or so) that abut like a puzzle work best, and sort of give the illusion of looking at a cracked and crevassed reef wall. After you cast these, they need to be kept moist and unmoved for 3 days, 7 days being much better. Believe me. They do. And you will need to mist them once a day. I just covered mine with a garbage bag and used a water bottle to mist it. I recommend an acid wash, as described above, once these have kured for a week.
19. If you make a rock or rocks you don't like, either use fresh cement mix to add some new bits, or break the rock up and use it as aggregate in your next batch - no waste is good.
20. The moister you can keep the cement while it cures, the harder the final rock will be - try wrapping it in a bag, or misting it while it cures. Supposedly, if you can let it sit for two to four weeks before starting to water kure, it will dramatically speed the kure time.
21. Dust your molding sand with oat flour for easy removal of surface sand. Thanks Rhody!
22. Mix molasses with your molding sand to give it more texture. Thanks Rhody!

Various things I have used and have worked for me for adding details:
1. Cemented Nylon String. Makes realistic tube worm/duster tubes. Make a thin paste of just cement, and dip small lengths of the sting in. Wipe excess off between fingers and lay onto the rock in desired figure.
2. Veggie Capsules. These can make little tunnels when laid end to end in the wet cement, and then covered with more cement. Or poke into outside edges to mimic polyp holes. Do NOT mix into the cement mix.
3. Nori Sheets. These can be wetted and formed into shapes or rolled into tunnels.
4. Balloons. Both the round and “animal” ones work. I find that filling them with water makes them stronger. Doubling them up works well too. Make sure that you can get the balloon out afterward - i.e. leave the knot sticking out.
5. Cardboard Rolls. Can be cut to form bracing, tunnels or for pillar shapes. Be sure to use it in such a way as will allow you to remove it after a few days of kuring. Hemostats work great for grabbing a-hold and pulling it out.
6. Tissue Paper. The white stuff you find in gift bags. Disintegrates quickly during kure. You can make little (or big) “salt bags”, that you can lay into the middle of larger rocks to give more holes for ‘pods and the like. Can be used to make caves and tunnels. Just use a small bit of paper, lay some salt in it and twist or tuck the ends – a small bit of cotton thread could be used to secure the package too.
7. Pasta. Must be cooked “Al Dente” before use. Do not mix into cement, it only makes a mess and is a pain to get out of the rock as it gets really hard and crunchy when the rock dries (ever scraped 3 day old pasta off a plate?).

Kured Rock that the pasta is stuck in...
Use to add spaces in the rock, or tunnels with spaghetti (at your own risk). Rigatoni adds a nice effect if placed just right. If you use pasta, you MUST keep the rock moist at all times – if the pasta dries, it will most likely never come out, ever.
8. Jelly. No, not like PB&J, but those toys, etc made of the product known as silicone jelly – often comes in wiggly balls. Also fishing bait worms made of the jelly/rubber. No need to lube them – they will release just fine.


Things that DO NOT work:
1. Vinegar/acid kuring. Does have its uses, but don’t expect it to kure your rock – it won’t.
2. Bio-degradable packing peanuts/Cheesy-poofs. I can find no way to really use these that is also safe for the tank.
3. Fish food pellets. That was really, really nasty. I don’t want to go there.
4. Uncooked Pasta. As pasta absorbs water, it expands, causing the cement to fracture and crack – cook it al dente if you really want to use it.
5. Alka-Seltzer . Doesn’t work. It dissolves too quickly.
6. Yeast. Doesn't work. pH kills the cells before they can respirate. Though during the Kure, this might be a speed option.
7. Co2. Ok – it does work, but only under high pressure. Adding into H2O will only make soda pop (carbonic acid), and eat away at your rock, causing fresh, high pH surfaces to be revealed.

Salt Release
If you used salt in your rock, it must be removed before kuring can happen. Salt will release in hot water much easier than it will in cold water, and boiling water works best of all. It generally takes two days to two weeks to remove salt, based on factors such as wetness of the slurry, aggregates used and density of the cast piece. Removing the salt will take several water changes. Boiling is also a viable option, and may also help reduce pH - hydrogen carbonate ions can decompose forming insoluble calcium (or magnesium) carbonate, which then are flushed away.

If you aren’t sure that the salt is gone, you can do a “Taste Test”. After draining and rinsing the rock (pick your largest/thickest piece), allow the water to drain out for a few minutes. Pick the rock up and use your finger to catch a drip of water from the bottom of the rock and taste it. If there is still salt present, the water drop will be salty. If the salt is gone, the drop will taste of mineral water and very slightly sweet.

Rock Kuring
Kuring your rock is the next hurdle. It is really, really best to leave your rock alone for at least a week before starting this step. According to Quikcrete reps, it takes 7-14 days for the rock to stop curing/hardening (though this process is actually going on for a lot, lot longer) - even though it looks and feels done. Testing standards say it takes 28 days to reach full strength and before testing for commercial applications can commence. By putting your rock in the kure bin too soon, you are wasting a lot of water, prolonging the hydration process and making weaker rock. Rocks during this 2-4 week period will naturally loose pH - from 12-13 at casting time down to 9-10, with NO WATER USED. I theorize that rock left longer, like 5 weeks, will only need a week or so of kure time (and a lot less water and effort!).

Kuring is pretty straight forward. Lots of time, and lots of water changes with adequate water volume, unless you have access to a reasonably clean waterway. This step is dramatically decreased if you wait until the 4-5 week range of your rocks life. Powerheads help force water through the rock and help the insides kure out. Adding heat to the bucket, upwards of 90°F will speed things along.

When your bucket kured rock quits leeching out white scum on the surface of the water, and stops leaving a white residue on the bottom of the bucket and on the rocks themselves, you can start checking for pH. Rock has been known to kure in as little as 2 weeks, but most bucket/bin kured rock takes 6-8 weeks to reach safe levels – some will take up to 3 months. Be prepared to wait.

To properly test for pH, change the water – use saltwater – saltwater is preferred since this is what the rock will be sitting in for the rest of its life. Feel free to use old water from a tank change, just test the pH prior to use. Let the rock sit in this for 3-4 days without air or powerheads – you want still, stagnant water for this. After the 3-4 days, give the water a bit of a stirring and check pH with appropriate test kit. If it is in the acceptable range of 8.0 to 8.6, it is probably safe to use. If not, continue to kure.

You can use any acceptable pH testing method. The test you use should have a testing range of 5-10 at a minimum. I like using Litmus Paper. It can read pH from 1-14, and is fairly easy to read. Litmus paper can be gotten at “Hobby Lobby” for $3.89 per 100 strips. These can also be used to test your reefs’ pH Litmus can also be found at pharmacies, online, and at other full service hobby stores, usually in the section that has things like “Magic Crystals”, and horseshoe/bar magnets – the “Science Section”.

Once kuring has finished - reads between 7 and 8.6 on pH, your rock can be used
If added to a newly established tank, you can go ahead and put it all in at once. If the tank is older, with inhabitants, you may wish to add a rock or two at a time, to allow the system to “settle” between each addition. Maintain pH testing for the first two weeks and buffer if needed.

Expect an algae bloom.
A few people, those who either have waterways to kure in, or those with really butch systems have reported no algae blooms, but I suspect they are the exception, not the rule. If your tank blooms, don’t panic. Most tanks bloom within the maturation period anyway. Double check your system for things like NO2 and NO3, and other algae causing symptoms and correct anything that isn’t up to snuff. Take all the normal steps to curtail the growth, but then just ride it out. If the bloom is caused by the rocks, the algae will soon deplete the readily available nutrients and starve itself out. If it doesn’t go away within a few months, then you should check into other reasons for the bloom.
New Tip! If you place your rock in tank with low light for two weeks to a month, you can avoid most of the bright green covering algae – low lights allow the rock to settle in without being attacked by algae so badly, or so it seems, IME…

[Insane Reefer]

And in conclusion, I'd like to address "Expectations". I have a feeling that some people are expecting the rocks they make to be as hard as cement blocks or cement stepping stone, because, after all, they are made with cement, so it should be, right? Well, in this case, no - they won't be.
Let's compare our slurry to a typical cement pour slurry.
First, poured slurry's are made with a higher ratio of cement then we usually use. Next, they add enough water that they can pour the slurry - much like an ice cream slurry. I've never been able to pour my slurry; we try to make ours as dry as we can and still have it stick together. Then take a look at the aggregates - they use silica sands and gravel, we usually use calcium based substances when we can - there is a marked difference in each of these as far as strength goes.
And finally, when cement is poured, they try to get it settled down - they drag tools over it to smooth it and make sure it is even and all that. We go for as much openness as possible, and we try not to pack the slurry if we can help it.
Looking at it like this might help people come to a better understanding of what a reasonable expectation of their rock might be.
Our rock is going to flake and shed. The more porous the rock is, the more likely it will be to do so. The better the slurry is made though, the less you will see of it. Maybe you have seen a box of real live rock just after shipping. If you have, you probably noticed the rubble in the bottom. Most distributors are not in the habit of making up the extra weight in a box with rubble - that would be bad business. Most of that rubble simply came from the rock during shipping. Calcium based rock is not the strongest in the world, and essentially, our rock is calcium based.
But flaking and shedding are not the same as brittle rock. Your rock is brittle if you can snap large pieces off after a month or two. Small bits rubbing off is not necessarily indicative of failed rock, those could just be pieces that didn't get adhered well.

My first piece of advice would be to wait. It takes a month for the curing process to reach near completion and the rock to reach something close to its final strength. If your rock seems brittle or flaky, beyond what you should reasonably expect, just leave it alone for a month, in a moist (not wet), warm environment, like a plastic bag. Some of the early salt rock I made seemed really brittle, too brittle to use, certainly, for the first couple of weeks. It was when I later found it again, in the bottom of a bucket outside, that I realized how nicely it had hardened up. If after leaving it alone, you can easily snap sizable portions off (golf ball sized?), then you have a problem.

My next pieces of advice would be to use a stiff bristled brush, like what you use to clean your grill, to give your rock a good once over when it reaches about four weeks old (or after the pH test in Jiffy Rock). This will remove about 90% of the shedding and flaking, if your shedding and flaking isn't due to rock failure that is. If you have done this and a couple of weeks later it is readily shedding, then I'd say you might have a problem.

Remember that even slight variations can make a huge difference. Humidity and Temperature at casting and during the cure can make drastic differences. A tablespoon of water can make a difference on smaller batches - too wet and too dry can be a fine line. Differences in the cement itself can wildly vary - every plant uses its own recipe to make the clinker. Differences in local materials used for the recipe can ofter vary with availability and cost. My white cement is going to be different then Neptunes' cement, and his, even from the same plant as Sunkools' may vary as well, from lot to lot.

Salt can mess up the strength of your rock, so if you used salt, think about that. If you added it upfront, with the aggregates, you may have over-mixed it and too much salt mixed into the batch. Try adding the salt after the slurry is mixed and ready - and just lightly mix it in.
A ratio of 1:3 or 1:4 is best for us. 1 part cement to 3-4 parts "other", which includes salt.
If you are trying Jiffy Rocks, do not remove the salt prior to baking.

And finally, realize that even the best made rock can still chip and shed once in a while. Moving it around in your tank, bumping it against each other (esp larger pieces), will inevitably cause bits to shed or chip off, unless you went for rounded ball like shapes, which seem to loose less, but also seem less porous and less attractive too.

I hope this helps a few people out there. I know that having something you worked hard on, that doesn't turn out like you wanted, can be disappointing. Hopefully this will help people understand what they should expect, and what they can do to correct it...

Well, I think that about covers my repertoire. I apologize for the length of this post, but hopefully some of you will find something of use…

I encourage the rest of you to take some time to write up your experiences and tips and share them with us – by sharing our experiences, we all learn and get better and better at making our own rock.

Good Luck, and Rock On!

[mmm55645]

I used quikrete water stop to attach some of my rocks(that are cured, water tests around 8pH).

I wanted to cure the rocks a bit longer just to be on the safe side, after using the quikrete water stop to fuse pieces together.

I have noticed that on some locations where I used the fast setting cement, there are white powder secretions coming out of the quikrete. In some places the power is shaped like a tiny icile, in others it looks like bright white salt slightly crusting small locations. The substance is not hard and crumbles easy if touched but seems to hold its form in the water. I don't think I used salt in the batch, but I might have used it in the mold and caught a piece in the rock without knowing it, but I don't think so.

Anyone know what this substance is?

I am wondering if I should not use these rocks in the tank until the secretions have stopped, or if the secretions make any difference? I am going to be cycling my tank with the rocks, I'm really not sure when it is safe to use them. If the rocks do need extra cycling time with the quikrete added, how much longer? The strange thing is that the pH is not testing high, even with the white secretions.

Quikrete water stop cement does not need to cure nearly as long as regular portland, correct? Would it be ok to put my quikrete fused rocks together without giving the quikrete time to cure? It is going into a new tank.

[mr.wilson]

The white crystalline formations are calcium precipitate from the hydration process. It's typical of all of the fast setting cement mixes. It's the same process that occurs with regular portland at a faster rate.

A slightly elevated PH is fine for a new tank with no fish or invertebrates. Quikrete doesn't raise the PH much, and not for long if it does.

I frequently use it to bond live rock and fill the tank the same day. You get a bit of cloudy calcium precipitate on the joints, but I've had no problems adding a few fish a couple of days later.

[crazedartist]

Wow that was a lot of reading! I've been out of the hobby for ages now... considering a reappearance. This thread definitely caught my interest.

I was thinking, I wonder if we can jumpstart the look of a coralline-encrusted rock using an artificial colorant. I see some folks have experimented with cement tints, but what about other marine-safe pigments?

For example, we know coralline grows on PVC... and we know PVC solvent leaves unyielding purple stains on things after evaporating...

(I know the solvent is not the same stuff as the PVC, but we know it's safe at least!)

Obviously I wouldn't want to dip rocks in the stuff because that would seal off all the yummy porosity. But maybe dabbing it onto what would be the top surface of the rocks... that still leaves loads of porosity underneath and also probably there would still be plenty of bare areas on top of the rock for things to attach.

There's also scarier substances like marine epoxy or marine paint, but I would worry that some of those would have "anti fouling" components since I technically _want_ fouling.

I seem to recall at some point a claim that acrylic paint (like artist's paint) is basically the same stuff chemically as the acrylic we use in our aquaria... but I don't really have any basis for that. Even if safe and durable, I suspect it's too rubbery to make coralline algae and coral fragments happy.

[Insane Reefer]

Originally posted by mmm55645
Anyone know what this substance is?

Hey MMM.
You didn't say if this was happening while it was curing or while it was kuring - if it is happening during Kuring, then it is nothing to worry about, but if it is happening during Curing, then read on.

What you have going on sound like two different reactions. One would be:
http://www.cement.org/tech/faq_efflorescence.asp
and the other would be:
http://www.cement.org/tech/faq_DEF.asp

Efflorescence is mostly harmless, and is a calcium based precipitate, as Mr Wilson indicated. Ettringite formations though, can be indicative of a potential problem. Not with it being harmful to the tank or anything, but a fundamental problem with the cement itself.

If I were in your shoes, I'd leave the rocks to cure for a week, then a week in a kure, and call it good to go. There isn't anything wrong with putting it in now, but those precipitates will deposit on the tank and be a pain to remove...

[Insane Reefer]

Originally posted by crazedartist
Wow that was a lot of reading! I've been out of the hobby for ages now... considering a reappearance. This thread definitely caught my interest.

Welcome to the thread, CrazedArtist!

I was thinking, I wonder if we can jumpstart the look of a coralline-encrusted rock using an artificial colorant. I see some folks have experimented with cement tints, but what about other marine-safe pigments?

Coloring rock has been a sort of disappointing quest. We can get colorants, made for cement, that are also "safe" in the tank, however the problem arises from a different angle. Most cement/concrete is made to be very dense and the surface area is smoothed to form a seal of sorts. When we make rock, we have a very open surface, and this leads to "carbonation", which is what we are ultimately desiring - rock as close to calcium carbonate as is possible to produce. Carbonation is the white powder that starts to show on our rocks after they are allowed to dry out fully. That white powder ends up "dulling" the original color until it is a pale shade of what you started with, and the older the rock, the lighter the shade tends to become. Thus, a lot more colorant is needed to make a realistic color that stays. The best luck I've had with cement colorants was by making a cement slurry of cement and very fine sand, that I made about as thick as latex paint, that had a lot of colorant in it, and then painted roundish patches on the rock. Cost less, and more realistic, but carbonation still dulled it down to pastel...

I seem to recall at some point a claim that acrylic paint (like artist's paint) is basically the same stuff chemically as the acrylic we use in our aquaria... but I don't really have any basis for that. Even if safe and durable, I suspect it's too rubbery to make coralline algae and coral fragments happy.

I've never heard that, but I think the idea is to mix it directly into the cement mud as you mix it, not painting it on; likely it would peel off if painted on. Krylon makes a paint that many use to paint their plumbing, etc, and it is supposed to be safe for use in the tank - it might work, or it too might flake off when that carbonation layer develops.

PS
I sent you the info you requested this morning - let me know if you need anything else, or if you didn't get it...

[mmm55645]

is it safe to put my rocks directly on the glass bottom of the tank and then add my DSB?

[Insane Reefer]

That is typically how it is done, isn't it?

Might use a stiff bristled brush to go over the bottoms of the rocks going on the base - someone reported a cracked bottom from MMLR, but I think they cast it directly into the tank, so dunno. Just knock off the pointy bits, if any, and you should be ok.

Pictures?

[mmm55645]

I thought that was how it was done, but I read somewhere to put pvc pipe underneath the rocks and another place on the web was saying to put the rocks on top of the sand, although I didn't really agree. I think the site was saying that sifters might be hurt by the rock or something, but I am not going to put anything that sifts enough to destroy populations of microfauna there, anyhow.


I was reading a book that I ILLed, and it had a section on MMLR. I'll have to enter a passage from the book. It gives some general advice about curing cement and argonite rocks but interesting thing is the book says that the rock doesn't need much time to cure if it is cured in a heavy brine solution or with some sort of acid--I will enter a quotation from the book later.

here are two of my rocks. The first two are the same rock from two views, the rock looks really solid but there are several holes and tunnels.

here is the other view

here is the another rock, one side has a nice shelf side but it is hard to see from this angle.

I really did not do that great a job of fusing the rocks together, in some places the fast setting cement contrasts with the normal portland;however, at one time these rocks were pile of random pieces. I guess in the long run the contrast won't be visible.
Oh, the leg on the first rock is a different color b/c I left that piece in the sand mold for a while, just to see what would happen. I like the first rock b/c, although it is steady, it looks like it is about to fall over.

[Insane Reefer]

Originally posted by mmm55645
I was reading a book that I ILLed, and it had a section on MMLR. I'll have to enter a passage from the book. It gives some general advice about curing cement and argonite rocks but interesting thing is the book says that the rock doesn't need much time to cure if it is cured in a heavy brine solution or with some sort of acid--I will enter a quotation from the book later.

Nice work on the rocks! Thanks for posting - post again when you have it all intank, please

I too have found this to be true with my JiffyRock experiments (and have posted such), especially when the rock is given a chance (or is forced) cure first as it was formulated to do.

However, after talking with several cement pro's, I think acid and salt are both prone to damage the cement at the base level, and hence you could have problems with cement failure after time - this could happen in a year, or twenty, or maybe not at all, but having your reef crumble would sort of suck, so I am looking into other ways of using a more basic solution, like the water we already use, and the air itself to carbonate our rock. I've had some interesting results using rainwater, but am preforming more experiments to try to form a consistent technique.

I would be exceedingly interested in that info though

[ddoering]

Hi All,

I've read through most of this thread, and had a couple of thoughts, although I'm not in a position to start experimenting, but hey, you guys out there that are experimenting, maybe you are bored and want to try something.

Has anybody used ice cubes etc while casting to make internal pockets etc, or will the ice melt too fast to give the concrete a chance to set up before it melts?

If the ice can last long enough for the concrete to set a little before it disappears, for those of you guys trying to force CO2, ever try dry ice chunks? just break some up and put into the concrete as you make your rock? It would sublimate and make voids, and as it turns to gas it would be pure CO2 inside the rock so it would be under some pressure and pushing into the rock? Maybe speed curing?

For people who want really porous lace like rock:
Has anybody made up a really wet, mostly portland mix and taken a natural sponge and basically just dunking and squeezing the sponge while it is in the mix and taking it out and letting it dry?

How about using some kind of cereal as the casting media to give you the pockets and rough texture on the outside, like trix or rice crispies? Give you something to do with that stale old cereal, and I imagine a short soak after the concrete hardens up will dissolve most of the cereal in short order? Would this prevent the issue with salt making the concrete more brittle?

Cheers,

Doug

[Insane Reefer]

Originally posted by ddoering
Hi All,
I've read through most of this thread, and had a couple of thoughts, although I'm not in a position to start experimenting, but hey, you guys out there that are experimenting, maybe you are bored and want to try something.

Welcome to the thread, DD
New idea's are always welcome - you never know until you ask or try...

Has anybody used ice cubes etc while casting to make internal pockets etc, or will the ice melt too fast to give the concrete a chance to set up before it melts?

Two problems with this:
1. The ice will melt in about what, 10-30 minutes? It will soak into the cement, turning the cement soupy, and too much water can ruin cement.
2. Whatever you use needs to be able to hold up for at least 2 or 3 hours to provide support, or the weight of the cement will often mush it down.

If the ice can last long enough for the concrete to set a little before it disappears, for those of you guys trying to force CO2, ever try dry ice chunks? just break some up and put into the concrete as you make your rock? It would sublimate and make voids, and as it turns to gas it would be pure CO2 inside the rock so it would be under some pressure and pushing into the rock? Maybe speed curing?

O2 is needed for the curing process, Co2 for carbonation. I think the Co2 would inhibit the curing process.

For people who want really porous lace like rock:
Has anybody made up a really wet, mostly portland mix and taken a natural sponge and basically just dunking and squeezing the sponge while it is in the mix and taking it out and letting it dry?

Cement is really, really alkali, meaning it can chemically burn stuff. I've left sponges in "less than clean" condition when doing cleanup after a casting session, and later found the sponge was sort of disintegrating. This was a synthetic sponge, but I imagine a natural sponge would be even worse. So not sure that is something I'd want to put in my tank. Not to mention that to make it strong enough to hold up under normal use intank, you would end up loosing most of the cool detail trying to thicken and strengthen the cast.
It is a really interesting idea though. I'll think on it and see if I can come up with an alternative to the sponge. Anyone else?

How about using some kind of cereal as the casting media to give you the pockets and rough texture on the outside, like trix or rice crispies? Give you something to do with that stale old cereal, and I imagine a short soak after the concrete hardens up will dissolve most of the cereal in short order? Would this prevent the issue with salt making the concrete more brittle?

Food = Bad As a general rule.
With food or products like food (starch packing peanuts, etc), you have one major problem that is almost always an issue.
They absorb moisture from the cement, which is bad for curing.
When they absorb the moisture, one thing almost always happens - when the cement goes dry, the remains of what was used absorbs some cement with the water, and those remains are little cement bits, with organic matter that may take a really long time to leach out, if it ever does.
Next with these types of "additives", you generally have one of two issues: when it absorbs the moisture, it collapses, taking the void with it, or, in the case of things like pasta or pelleted foods, they expand, and continue to slowly expand, causing the cement to crack and fissure around the items, often ruining the rock.

Also, sugar is worse for the hydration phase than salt is, so sugary foods would be even worse than salty ones.

I've found that for making small tunnels, you can't go wrong with silicon jelly fish bait or silicon jelly kids toys - they are cheap, easy to release, and reusable too.

But keep the thinking cap on - sometimes even the silliest idea's do pan out, you just never know.

[TheDIYguy]

Awesome! When I set up my 55 gallon, I'm going to make these!

[Insane Reefer]

Originally posted by TheDIYguy
Awesome! When I set up my 55 gallon, I'm going to make these!

Welcome to the thread, and RC, DIYguy!

Awesome! Let us know how it goes, ok?

[Insane Reefer]

I have a question, and since we have some smart people, thought I would ask here.

You know I am trying to devise a steam box to produce more rock more quickly using the JiffyRock method, but without the high heat needed in the oven to produce the needed steam. I've talked about different idea's, but none have seemed just right.

For those who don't remember, the "industry" uses room sized kilns that are much like a steam sauna - they bring the temp up to 150-180°F, hold it there for a couple of hours, then shut it down and leave the bricks in the moist hot box for a total of 12-24 hours.

So. I thought hard about it and came up with this idea.

What about recycling a non-working deep freezer? It is certainly insulated, and sealed, resistant to moisture, has racks in it, and should be able to withstand the low temps needed.

One would simply need to use a holesaw to bore an appropriate hole through the side, attach a tube or pipe that runs to-from whatever we boil the water in (and reseal the bore), with a pressure valve between the "boiler" and the "steam box".

Thoughts? Reasons this wouldn't work? Better ideas?

[Noise]

Originally posted by Insane Reefer
I have a question, and since we have some smart people, thought I would ask here.

You know I am trying to devise a steam box to produce more rock more quickly using the JiffyRock method, but without the high heat needed in the oven to produce the needed steam. I've talked about different idea's, but none have seemed just right.

For those who don't remember, the "industry" uses room sized kilns that are much like a steam sauna - they bring the temp up to 150-180°F, hold it there for a couple of hours, then shut it down and leave the bricks in the moist hot box for a total of 12-24 hours.

So. I thought hard about it and came up with this idea.

What about recycling a non-working deep freezer? It is certainly insulated, and sealed, resistant to moisture, has racks in it, and should be able to withstand the low temps needed.

One would simply need to use a holesaw to bore an appropriate hole through the side, attach a tube or pipe that runs to-from whatever we boil the water in (and reseal the bore), with a pressure valve between the "boiler" and the "steam box".

Thoughts? Reasons this wouldn't work? Better ideas?

If you wanted to keep it on the cheap, couldn't you use something like a room humidifier (one that uses hot steam and not a cool mist )? If you use an upright freezer, I would think this would work out and no drilling would be necessary. But perhaps this isn't hot enough for what you are looking for. Or perhaps one of those home clothes steaming units.

[Insane Reefer]

Hey Noise,

I'm not sure either of those would produce enough steam, at the correct temp range, but I will look into them and see.
Thanks for the idea!

I've talked to a couple of people about this now, and no one seems to see any reason this wouldn't work.

Though one person pointed out that since this will be an outside setup, there might be legalities about having a deep freeze accessible. I know when you dispose of one, you must remove the doors so kids can't get trapped in them, but anyone know what the law states about keeping outside, but locked?

[BigSkyBart]

wow, it's been a whille since I've dropped in on the thread, glad to see it's still up, running & growing new ideas along the way.

I've missed the "steam cure segment" but have a few ideas for what you describe needing, and the steam generation portion is from personal experience (simple & IMO safe)
or do you already have steam production under control?

I'll try to get a picture & description ready for posting later