Hydraulic cement for dry rock.

[SteelMastiff]

I have a fair amount of small light weight pieces of dry rock lying around and I've been contemplating making some arches or cave structures out of them. They are really too light and small for stacking, and I haven't had much success using water weld epoxy in the past, so I am searching for alternative means to bond these small pieces together.

I was just wondering if anyone has ever used a quick setting Hydraulic Cement for this purpose? I am no Chemist, and looking at the MSDS sheet on this just makes me cross eyed.

Here is the MSDS list.


SECTION II "“ HAZARDOUS INGREDIENTS/SARA III INFORMATION
OCCUPATIONAL EXPOSURE LIMITS VAPOR PRESSURE WEIGHT
HAZARDOUS COMPONENTS CAS NUMBER OSHA PEL ACGIH TLV OTHER mmHg @TEMP PERCENT
CRYSTALLINE SILICA 14808-60-7 .1 MG/M3 (1) .1 MG/M3 (1) PROP 65 N/A 40
PORTLAND CEMENT 65997-15-1 15 MG/M3 10 MG/M3 NOT ESTAB N/A 40
HYDRAULIC CALCIUM "“
ALUMINATE CEMENT 65997-16-2 15 MG/M3 10 MG/M3 NOT ESTAB N/A 15
CALCIUM HYDROXIDE 1305-62-0 5 MG/M3 2 MG/M3 NOT ESTAB N/A <5
(1) TIME WEIGHTED AVERAGE
No toxic chemical(s) subject to the reporting requirements of Section 313 of Title III and of 40 CFR 372 are present

 

[madean]

I have been wondering this as well.

 

[mgargiullo]

Interesting question. This would be a grey way to get them to stick. I know that it's very caustic. Is be interested to hear from a chemist.

 

[uncleof6]

You have to be careful with the type of cement that you use. In the forums there are many types of cement used, and recommended. Well..there are just as many issues with cure time running into months and longer. For rock, adding things such as rock salt, and oyster shell, only exacerbate the curing problems.

The original recipe (e.g. the "real" recipe) from GARF (invented the concept) calls for a White Cement, low alkalinity type. Riverside would be preferred (track record.) This is a specialty cement, (read: no home depot/lowes) used as a base for plastering swimming pools, and is available from suppliers dealing with pool construction.

There are probably better solutions than cement, for sticking rocks together. If going to the trouble to stick rocks together, making your own rock would probably be more rewarding, with unlimited possibilites for shape/configuration—as long as you stick to the original recipe, rather than forum machinations.

 

[DavidinGA]

I used hydraulic cement to fuse my dry rock together in my 210gal and have not had any issues.

Hydraulic cement has been used for this purpose for a LONG time in the hobby and no negative issues have been discovered that I am aware of.

 

[SteelMastiff]

You have to be careful with the type of cement that you use. In the forums there are many types of cement used, and recommended. Well..there are just as many issues with cure time running into months and longer. For rock, adding things such as rock salt, and oyster shell, only exacerbate the curing problems.

The original recipe (e.g. the "real" recipe) from GARF (invented the concept) calls for a White Cement, low alkalinity type. Riverside would be preferred (track record.) This is a specialty cement, (read: no home depot/lowes) used as a base for plastering swimming pools, and is available from suppliers dealing with pool construction.

There are probably better solutions than cement, for sticking rocks together. If going to the trouble to stick rocks together, making your own rock would probably be more rewarding, with unlimited possibilites for shape/configuration—as long as you stick to the original recipe, rather than forum machinations.

I appreciate the response. I have about 60 lbs of dry rock laying around that I really want to make us of; about 25 lbs of which is rather small and porous, this is the rock that I would like to bond together. The remaining rock is larger and can be stacked securely with ease"¦ I have contemplated making some ledges in the future, so I really appreciate the info and advice.

I used hydraulic cement to fuse my dry rock together in my 210gal and have not had any issues.

Hydraulic cement has been used for this purpose for a LONG time in the hobby and no negative issues have been discovered that I am aware of.

Thanks for the first hand knowledge response. I have used it in the past for construction, and it seemed like it might fit the bill for what I am trying to achieve. I have 10 fish in various stages of quarantine at the moment, and wanted to get this rock cycling ASAP so when it comes time to start introducing them into the DT I can mix up the rock work in hopes the already established have more to focus on than just beating the crap out of their new tank mates.

Thanks again for the quick response"¦:thumbsup: