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  #1  
Old 01/05/2008, 05:25 PM
JohnL JohnL is offline
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This thread was automatically split due to performance issues. You can find the rest of the thread here: http://archive.reefcentral.com/forum...5#post11528635
  #2  
Old 01/05/2008, 05:25 PM
lowfi lowfi is offline
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wheres the cement?!

Hey everyone,

Where can you find that Portland Type I white cement? I cant find it anywhere. The closest I have found is Portland Type I/II gray color for ~$8 a bag. I found the white grout that you can use but I want to stay away from that due to all the silica sand, etc. Does anyone have any tips to find this cement?

Thanks,
Sean

PS: I bought some salt at HD, its under the mortens brand called solar salt...is this the right stuff???
  #3  
Old 01/05/2008, 05:29 PM
lowfi lowfi is offline
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Forced the split...


~~NiCe~~

  #4  
Old 01/05/2008, 05:32 PM
lowfi lowfi is offline
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Will type II work?
  #5  
Old 01/05/2008, 05:46 PM
treny treny is offline
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yes..
  #6  
Old 01/05/2008, 06:46 PM
Insane Reefer Insane Reefer is offline
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Thread Split - Woot!

Anyway, Lowfi, almost any cement will work. If you really want the white portland, be aware that it costs usually twice what the grey does. Find a masonry supply place in the yellow pages - they will have it if anyone does - I've yet to see "specialty" cements at a Big Box Store like Lowe's or Home Despot. If they don't, ask for Type 5, which is formulated for marine use. And then if they don't have that, use whatever you can find.

And as long as you got the crystals, then you got the right stuff - pellets and cubes can be used for doing specific holes and the like, but the crystals are what you mix in as an aggregate...

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  #7  
Old 01/05/2008, 07:28 PM
lowfi lowfi is offline
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insane reefer check yer pm's
  #8  
Old 01/05/2008, 09:13 PM
Insane Reefer Insane Reefer is offline
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Gotcha Lowfi
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  #9  
Old 01/05/2008, 09:30 PM
customcolor customcolor is offline
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insane reefer
could you use blasting sand (which is industrial quartz, aka silica sand) as an additive to the cement?
  #10  
Old 01/05/2008, 11:18 PM
Insane Reefer Insane Reefer is offline
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Sure you can Custom, but many folks have a hangup about silica sands. If you use calcium based sand, your rock has a higher over-all calcium content, which may be better as the more Calcium Carbonate in the rock, the more like RLR it becomes. There is also a vague potential for "Alkali-Silica Reaction" when using silica...

Personally, I use Calcium Carbonate from the feed store, but I know that several people here have used silica sands - both blasting sand and playsand, to make rock, and they don't seem to notice a real difference, so, IMO, it comes down to preference...
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Old 01/05/2008, 11:30 PM
customcolor customcolor is offline
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now is this split 5 or 6 now? this has to be like the largest tread out on rc now!
  #12  
Old 01/05/2008, 11:40 PM
Insane Reefer Insane Reefer is offline
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Warning - Super Long Post!

v7.0

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 with a high over-all calcium content, but it is expensive.
Crushed Oyster Shell - AKA "OS". Any shell will work, but OS is very cheap at feed stores.
Calcium Carbonate - Called Calcium Carbonate for “Feed Mixing” (aka Chicken Grit or Scratch Sand). 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 than $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!
23. Replace up to 1/3 of your cement with “Hydrated Lime” – this reduces the over-all alumina content of the cement (and boosts the calcium content) and makes it more resistant to potential “Sulphate Attack”.

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 immature rock – it won’t. A weak solution can be used on FULLY CURED rock to hasten the leeching of the Calcium Hydroxide, but using it too soon, or using too high of a concentration is detrimental to the cement. If you must use it, use regular vinegar at ¼ cup per gallon of kure water, and use it only if your rock is at least a month old or the equivalent (steam cured, etc.).
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 at least 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 9-11, with NO WATER USED. I have been finding that by leaving the rock alone, my average kure takes less then 2 weeks (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 really 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.

Continued Below....
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  #13  
Old 01/05/2008, 11:41 PM
Insane Reefer Insane Reefer is offline
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Continued From Above...

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…
--------------------------------------------------------------------------

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 “mud” 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 mud; we try to make ours as dry as we can and still have it stick together. Now take a look at the aggregates - they use dense 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 mud 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 mud 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 mud is mixed and ready - and just lightly mix it in.
A ratio of 1:3 to 1:5 is best for us. 1 part cement to 3-5 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!
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  #14  
Old 01/07/2008, 10:59 AM
michaelalan michaelalan is offline
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Insane reefer has stated earlier that some rocks made with salt may fail. I am sorry to say that I am experiencing some of this now. These rocks have been in my aquarium about 6 months now. They are not crumbling, but splitting down the middle.

I’m going to list the various methods I used to reduce the pH so that if someone else ends up with this problem and used similar techniques then we can figure out the variable that is causing the splitting.

One piece was attached to a piece of live rock to make it level and therefore it has a small amount of weight on it. It is splitting down the middle in two different areas.

The other rock is simply a round piece with no other rocks or weight on it. It’s splitting long ways.

In curing these I boiled them and or added 10% vinegar to the solution to reduce pH.
  #15  
Old 01/07/2008, 01:48 PM
lowfi lowfi is offline
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maybe too much salt?? maybe need some sand to give it some strength to the mix?
  #16  
Old 01/07/2008, 01:52 PM
lowfi lowfi is offline
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OK i have a question regarding cement type. What types can you not use and why? If i remember correctly you can use type I,II, & V. What about type III? Why cant you use this? According to wikipedia..here are the differences between types. Are any of these large enough to make a difference?

Type I
55% (C3S), 19% (C2S), 10% (C3A), 7% (C4AF), 2.8% MgO, 2.9% (SO3), 1.0% Ignition loss, and 1.0% free CaO.

Type II
51% (C3S), 24% (C2S), 6% (C3A), 11% (C4AF), 2.9% MgO, 2.5% (SO3), 0.8% Ignition loss, and 1.0% free CaO.

Type III
57% (C3S), 19% (C2S), 10% (C3A), 7% (C4AF), 3.0% MgO, 3.1% (SO3), 0.9% Ignition loss, and 1.3% free CaO.

Type V
38% (C3S), 43% (C2S), 4% (C3A), 9% (C4AF), 1.9% MgO, 1.8% (SO3), 0.9% Ignition loss, and 0.8% free CaO.

If you would like to read the descriptions and other information on Portland Cement follow the link, I dont feel like pasting it all into the window...

http://en.wikipedia.org/wiki/Portlan...ortland_cement

Cheers,
Sean
  #17  
Old 01/07/2008, 01:55 PM
lowfi lowfi is offline
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I & III are very similar...
  #18  
Old 01/07/2008, 06:09 PM
Insane Reefer Insane Reefer is offline
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MichaelAlan, that is a complete and utter boo
Could we get some pictures of that?
Though I might go out on a limb and say that it might be possible that boiling the rock in acid might have been a bit of overkill...

I could go into a whole spiel about what the industry says about Chloride and Cement. Sufficit to say, salt is not good for cement. Period. Especially cement destined for use in saltwater. And porous cement has a greater chance for failure than dense cement does. Which is sort of a "Catch 22" - we need the rock to be porous to fulfill its required duties, but by being porous it is at higher risk from Sulphate Attack and Chloride Attack.

And subjecting rocks to temps over 160°F (boiling acid???) can also cause problems - mainly in the form of ettringite, which can literally split rock apart. This is why I have been looking at other ways to make rock - the JRM currently uses high heat to create steam, but the high heat can potentially cause DEF (Delayed Ettringite Formation) - so can boiling rock to speed the kure - never let the water get above 160°F (the hottest most of our water in our houses are anyway) to avoid this problem.

Then, when you remove the Calcium Hydrates from the matrix of the rock, (kuring), you then further handicap the cement in terms of susceptibility. That is why I've been on the whole "carbonation" kick. If, instead of leeching the calcium hydroxide out of the rock, we encourage a carbonate layer to form, the rock has a higher resistance to chemical attack while still being safe to use - the carbonate layer "seals" the rock in a way.

And then this also sort of leads to Lowfi's question. There most certainly are differences in cement. By slightly changing the composition of the materials used to form the clinker, cement can be changed to preform differently. In a perfect world, we would all have access to "Type 5 (V)" or "Type HS" cement - cement formulated to withstand the chemical attacks that sea water can bring against cement. High Alumina cement is also a choice for marine environments, but all of these types of cements are a denser, less porous cement, so again, the Catch 22. Though personally, if I could get it, I would use either Type V or HS.

Cement Types
Type I - Normal (Can be used)
Type II - Moderate Sulfate Resistance (Better than I)
Type III - High Early Strength (No point)
Type IV - Low Heat of Hydration (No Point)
Type V - High Sulfate Resistance (Best to use)
Type GU - General Use (Ok to use)
Type HE - High Early-Strength (Pointless)
Type MS - Moderate Sulfate Resistance (Better than I or GU)
Type HS - High Sulfate Resistance (Best to use)
Type MH - Moderate Heat of Hydration (Pointless)
Type LH - Low Heat of Hydration (Pointless)
Type HAC - High Alumina Content (Good/best to use)
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  #19  
Old 01/07/2008, 08:18 PM
a1amap a1amap is offline
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Quote:
Originally posted by michaelalan
Insane reefer has stated earlier that some rocks made with salt may fail. I am sorry to say that I am experiencing some of this now. These rocks have been in my aquarium about 6 months now. They are not crumbling, but splitting down the middle.

I’m going to list the various methods I used to reduce the pH so that if someone else ends up with this problem and used similar techniques then we can figure out the variable that is causing the splitting.

One piece was attached to a piece of live rock to make it level and therefore it has a small amount of weight on it. It is splitting down the middle in two different areas.

The other rock is simply a round piece with no other rocks or weight on it. It’s splitting long ways.

In curing these I boiled them and or added 10% vinegar to the solution to reduce pH.
Quote:
Originally posted by: Insane Reefer
MichaelAlan, that is a complete and utter boo
Could we get some pictures of that?
Though I might go out on a limb and say that it might be possible that boiling the rock in acid might have been a bit of overkill...
Not Boo
I can vouch for this. I made some DIY rock 1.5 years ago and it has crumbled and cracked. After playing with the mixes I feel it is a combo of 2 much salt and not allowing the concrete to cure properly before trying to Kure for ph. I will try to get pics up tonight when I get off work. IMO the rock crumbled because of a improper cure then Kure. The rocks that split was more directly related to how the salt lined up and made a weak area and the improper cure to Kure timing took care of the rest.

I have since made new rock following the ideas on this thread and used less salt and after 6 months it looks great. I also used Thorite cement per mrwilson to attack some live rock to my concrete. since it was a small amount of cement I kept the rock damp,waited till it cured and put it right back in the tank.
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Last edited by a1amap; 01/07/2008 at 08:23 PM.
  #20  
Old 01/07/2008, 08:57 PM
Insane Reefer Insane Reefer is offline
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Boo - as in bad/sad, not Poo as in BS! LOL!
Wasn't saying I didn't believe Michaelalan, I was commiserating with him. If it came across any other way, I sincerely apologize!

But thanks for posting your experiences to the thread, A1amap, by sharing our experiences - good and bad, maybe we can come up with a (can I say it?!?! ) , Cure
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  #21  
Old 01/08/2008, 07:10 PM
Insane Reefer Insane Reefer is offline
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Exclamation MLR XTREME...

It's on.

MRS (Mini Rock Sauna) has passed a trial run tonight. I came up with a "doohickey" to channel some of the condensation back to the PC and it is performing much better now. I used items I found in the plumbing box in the garage, but a more permanent solution will be devised. For now, I am using a nylon reducing hose barb which just happened to slip over the original "valve stem" of the PC, connecting to the copper doohickey, kind of bent like a question mark, going to a nylon elbow that goes to the vinyl hose that connects to the igloo itself. I will post pictures with a full write-up when I have proof of it's functionality.

I was able to reach 155°F, with steam enough to almost scald myself when I went to look and see what was going on inside the igloo. The igloo did not appear to take any damage from the steam.

So. I sold a small load of rock the other day, and as my hubby and I agreed, I used the funds to make a stock order from Sealife Inc - a bunch of ricordea and a few other things.

But I still haven't gotten "the perfect rock" for my 'Cube, so, this is going to be like one of those DIY Extreme shows. I have 5 days before the stock arrives, give or take. So I need to have rock NOW. I figure the stock will be ok for a few days just hanging out, but this is the fire under my butt to finally cast and choose a piece of rock.

Tonight I am going to cast 2 pieces fit to my 'Cube. After 16-18 hours, I will remove them from the casting bin and proceed to steam them in the MRS for 4 hours, with a 2 hour "ramp up and down" period on each end of the steam period. The will then go into a very weak vinegar solution for 24 hours, then 3 days of wetting and allowing it to dry (the idea is to encourage carbonation). I will then test the rock with a standard 3 day pH test. And post my results. If need be, I will follow up with a few days of additional kuring.

And then you guys will get to choose the rock I use of the two I will have made

Wish me luck!
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  #22  
Old 01/08/2008, 07:31 PM
silence88 silence88 is offline
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hi again insane
i have some more questions , i whent down and got some portland type I&II, silica sand and solar salt from a home depot in the states, but iam haveing a hard time with the calcium carbonate sand from the feed store, is what iam looking a large grain grit sand like for birds or a fine powder? i asked for calcium carbonate but they call it sodium cloride is it the same thing?

i made a test rock with some portland, sand and a bit of CC&OS and salt, casted it in sand and iam going to cook it tommorow when i cook it do i wrap it in tinfoil or just put it in the oven at 450 with a pan of water for about 6 hours then take it out and dunk it in hot water several times and then a bath in 10% vinegar for three days then in FW for afew days with daily WCs dos that sound right?

and one important thing i was wondering is, the fumes/smell of the rock wile cooking do you know if it is bad for fish or birds? i have three FW tanks in my kitchen and my moms starling is in the upstairs kitchen i could move the bird but my mom isent to happy about me cooking rock in her oven, will it make a mess in the oven at all?

sorry for all the questions
  #23  
Old 01/08/2008, 09:35 PM
customcolor customcolor is offline
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now INSANE you say you can use chicken scratch. well i found some at fleet farm but didnt buy it cuz i saw alum. oxide was in it also. was it safe to use?
well trip wasnt wasted though i got some crushed shells
  #24  
Old 01/09/2008, 01:32 AM
Insane Reefer Insane Reefer is offline
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NP Silence - never be sorry for questions you've asked.

You are looking for the larger "sand" sized Calcium Carbonate. I've seen it in two different sizes locally - one is pretty chunky (like the brown cement sand Quikrete sells), and is what I prefer, the other is sugar fine, like what we would use in our tank for the DSB. You have to be careful though, and make sure you get Calcium/limestone based grit and not the Granite (or other?) based grit.
Did they try to sell you Sodium Chloride or Calcium Chloride? Neither is what you were looking for in this instance - SC is Salt like table salt, CC is also a salt, but is used to speed the initial set of cement (and to de-ice driveways) - I use this in my personal mix so I can handle pieces earlier (and I think it slightly speeds the cure as well), but it isn't something you would use as an aggregate.
You might also look at your local big box stores - Pulverized Limestone or Limestone Sand are pretty much all the same thing.

And I had a gent from the UK PM me the other day, and he had found something called "Recycled Crushed Glass" - a very intriguing idea - recycling glass into sand. I've not seen this stuff around, but maybe someone else has? I'd be interested in a bag just to see what it is like, if for nothing else, but this might also be an idea for a sand aggregate. So if anyone spots any, get me the name of the chain and a SKU if possible. Thanks!

And as far as steaming the rock goes, please reconsider using the "high heat" variation.

There is a pretty good chance that baked rock will develop problems down the road, and even though I've made no bones about the potential problems this method could cause, I'd still feel bad if people came back with a bunch of failed rock, especially when I think I've found a better way to do it. Now if you are just curious, or making sump rock, then that is ok, but if things go as planned tomorrow, I will do a write-up of the "low heat" method, which should produce much stabler rock. In fact, I've emailed "JohnL", the mod, to see about having the old method post deleted so there won't be the potential for people to get confused.

It sounds like you have a pretty firm grip on the procedure, however, the vinegar bath is 1/4cup per gallon of water, not 10%. I would NOT wrap the piece in tinfoil, but line the bottom of the oven with it, as well as "cap" the vent under the top rear burner with foil. I'm sorry, but this will require you to clean the oven when you are done or your mom is gonna kill you. No matter how careful you are, you are going to get sand in the oven and the steam will lift any grime that is in the oven and get sort of icky.
And I would imagine that the fumes are not great for birds, but it didn't seem to bother the cats, dogs, people or tanks - birds are so sensitive to stuff like that, I'd be really, really careful. Block off all the vents to that room, and block off the kitchen with a sheet or blanket to keep the fumes contained, and run the hood fan, and if it is warm enough, put a fan in the kitchen window, venting outward.

I've been pimping the chicken grit for like the last 6 months, Customcolor
I don't know enough chemistry to know if aluminum oxide would cause a problem. It could be that this would create a "High Alumina Content" cement and be awesome - aluminum powder can create an air entrained effect and create voids, but too much alumina can be poisonous. So it might be bad. I don't know. Maybe someone else can offer their opinion. What % was the Al2O3? What was the bulk of the content? Are you sure that this stuff was for feeding chickens? You could always go to a different feed store and see what they have (or call)...
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  #25  
Old 01/09/2008, 01:52 AM
lowfi lowfi is offline
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Is it possible to update the methods and time frames of procedures to kure the rock? its all beginning to jumble together
 

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