Aragocrete

Hey, anyone who's made a lot of this successfully. Have you found any difference between cement types? Is one better than any other? If you've only used one type successfully, what type?

Add in some shaved plastic and some big crush coral and you would be very happy...

I would recommend the white portland cement.  I looks better and only requires a fraction of the curing time of standard portland.

Let me know if you have any more questions.

Great suggestions everyone thanks, BTW actually all portland cements require approx. the same cure time it just depends on amount of water used, temp., and consolidation method. Type III gains early strength the fastest but as adam said it's not pretty, sort of a clay brown, Type I is the white and doesn't gain as much strength in the long run as II or III but is much better in architectural applications, which is essentially what I'm doing so that should work. I was concerned about the higher amounts of alkali in type I white but it sounds like it works just fine.

The plastic shavings sound good, and I have an abundance under my table saw at the moment thanks to a remodel I just finished who wanted a lot of flex trim, so I'm good there. I do have cheerios (thanks mark), and aragonite sand, I'll pick up a bag of crushed coral at F4U on my way home today and the cement at HD on my way to work. So I guess tonight is experimentin' time thanks guys I'll post some pictures and info on my results.

 

Gotcha, sorry I used to mix concrete ALOT, but I understand now. BTW
(concrete nerdness again) concrete theoretically never reaches it's full strength, It continues to harden as long as there's available moisture for the cement to bond with. 96 year old footings have been broken apart and still had curing (hardening) occuring in the centers of the members.

My fish geek isn't quite up to par yet so I have to throw out cement geek whenever the chance comes up.

Jake, what's the best way to cure (your meaning) fresh aragocrete, saltwater soak in a bucket, or would fresh work better due to lower pH?

As Mark said.  Freshwater.

If you continue to see a high pH after a week or two you can always add some vinegar (or other acid) to help the process along.

Also as Mark said, I would check out GARF's web site.  You should find some good information there.

Just covered up my first piece, a three legged table with a hole through the middle. Looks like an artsy 70's chair . Mixing went well, and I mixed some twisted plexiglass shavings into the top layer. We'll see in 21 days if it acheives sufficient compressive strength for my application !

So far so good, I stripped the first piece yesterday and cast two smaller ones today. Looks great and I love the fact that with a little ingenuity I can make a great variety of shapes and characteristics in my rock. I have added plastic shavings to my mixes so far and plan on trying cereal and pasta for porousity tommorow.  I'll continue to post updates here as I go. I'm sure many of you have done this before, but maybe this will benefit any Newbies out there interested.

Garf suggested pasta for it's shapes, but makes sense that cereal would break down easier, I intend to soak, boil, and scrub the food based rocks thoroughly anyway. Maybe I'll start with just putting pasta on the surface so it's easy to remove.

I did one with regular cement and the rest with white cement. I would cure in the mold for one full day, (the one I took out after 6 hour broke). I cured for 6 weeks before the PH would stay below 9. I use a cup of white vinegar from day 4 until I used up a gallon, and changed the water every day. If you look at the picture on http://www.gurr.org/aquariums.php you can see it week or so after introducing fish. The rocks with color are natural rocks that I used for seed. I had a lot of mat algae until I used some Activated Alumina to remove Phosphates. You can see what the rock looks now in the pictures in my post of the sale/trade section.
http://www.utahreefs.com/forum/forum_posts.asp?TID=1967&PN=1