Rock work cracking thru the middel, Scared it will fall

[zcedric]

Good day Volks

Maybe some of you have hydraulic cement (lowes) experiences!

So I had 60 pounds of rock and i cement them together with hydraulic cement. After 2 hours everything was hard and i could lift the rocks in one piece into the aquarium.
Now after two weeks the cement starts to break and fall in little pieces down to the sand. Rock start to crack thru the middle like it has a lot of tension from maybe the cement drying all the way? Some rock split in half way thru.
I did not shake on the rock work yet. But it looks like it will colaps.

Somebody has.. had the same problem?
Pictures are hard to make but I can try tonight.

Thanks

 

[hijinks7]

Your problem is hydraulic cement. It doesn't like the ph levels and will start to crumble away after time.

 

[zcedric]

Your problem is hydraulic cement. It doesn't like the ph levels and will start to crumble away after time.

So.. its litterly **** up. haha
Anyone has a solution for it.. it not like i can just clean it. haha

 

[hijinks7]

So.. its litterly **** up. haha
Anyone has a solution for it.. it not like i can just clean it. haha

I don't think the cement will hurt your tank.. but i'd go in with epoxy and fix things back together if you can

 

[zcedric]

I don't think the cement will hurt your tank.. but i'd go in with epoxy and fix things back together if you can

so you suggest to remove the rockwork.. clean it a little and then use what kind of epoxy?

Because what ever I have atm does not look nice and all the cement falls on my nice white looking sand.

 

[hijinks7]

I mean.. I'd pull out the rock clean as much as I can and use epoxy to hold the rock together.

 

[HB AL]

A pic would really help. If your talking big heavy rocks, no sand to absorb the potential impacts it might be a ticking time bomb. If you can get them fused back together with some epoxy and superglue and add in some support then it should be ok, again a picture of the issue will help guys come up with a permanent solution. If they did fail the distance of the collapse might be a non issue if it's just a couple inches. If possible I would add some temporary support till you find a permanent solution.

 

[zcedric]

I mean.. I'd pull out the rock clean as much as I can and use epoxy to hold the rock together.

what kind of epoxy did you use if you did?

 

[hijinks7]

any marine 2 part epoxy you get from a big box store will work

 

[Porpoise Hork]

I tried multiple ways of securing the rock in my displays and decided that glues, epoxy's and the like just don't hold up long term. I have spent countless hours taking my time to build these super elaborate aquascapes only to have them get broken or simply fall apart because the corrosive SW environment broke the adhesive bonds in the glue/epoxy. For me the only ways to ensure it will stay where I put it is to either go with free stack using larger pieces that critters like turbos cannot move. Now for more elaborate displays like bridges and such, I like to form a stand from PVC that's filled with sand on the bottom, drill through the rock and pvc then use zip-ties if needed to secure it all together.

 

[DangerDave]

You can try fiberglass or acrylic rods placed into holes you drill in the rocks. They give a good physical connection you can reinforce with glue or epoxy. Good luck!

 

[Porpoise Hork]

I have used acrylic rods with good success. They do become nearly invisible once they are in the tank.

 

[chefjpaul]

All you need is emarco, zipties and patience.

Jb water weld works best if in a pinch. It holds very well.

 

[Crabby48]

All you need is emarco, zipties and patience.

Jb water weld works best if in a pinch. It holds very well.

Does the eMarco hold up long term with out zip tie

 

[chefjpaul]

Does the eMarco hold up long term with out zip tie

Yes, I just use them to hold until its dry and stable