Rock wall construction vs. gravel and time

[beviking]

I plan on constructiong a 3" wall using slate pcs. Foreground will have ~2" gravel. The wall will sit on the ~2" and have ~3" of gravel behind it so you'll be looking at a "stone wall" like you might see around a garden or border of property.
My plan is to use pcs that are 2" wide (front to back) by whatever length. The bottom most piece will be 4-5" wide so the gravel behind will hold it in place. I also plan on using silicone to hold the pcs together.
Any input as to whether this thing will slide forward over time? Would epoxy be the better adhesive to use?

 

[kveeti]

I am currently constructing a rock wall for my new tank, very similar in idea to what you are doing (like the garden border thingy). However I’m not using slate, just regular rocks. My wall is 2” high. Pic:

OK, now in my old tank I made a wall partition with it sitting on gravel, and the section behind it was supposed to be higher. The wall did not slide forward, but I can tell you the difference in height is no longer what it used to be. It will even out over time in my experience. I have to keep taking gravel from the front and re-piling it behind.

My old stone wall was made with flat stones glued with silicone. After 2 years, some of the pieces are dislodging. Rough stones that were put together with silicone the same length of time ago are still holding, even when tugged at. So I’m not 100% sure about slate.

So I have come up with a new plan for my new tank. Only time will tell if it’s a good plan or not. First, I am using epoxy putty. It dries rock hard, it is great I love it. I filled in any joins that showed with silicone and a sand/gravel topping.

Read this thread http://www.aquariacentral.com/forums/showthread.php?t=50971 in particular the terracing done by TwoTankAmin.

Since the base of my new tank even at the lower level will have a certain amount of gravel (as in your 2 inches), the base of my wall will be that height in Styrofoam and my rock wall will sit on that. Therefore, no gravel sliding underneath it. I intend to have this set up for a very long time, so I am also going to silicone the Styrofoam to the tank floor. If at any future date, I wish to change things, I figure the substrate will hide any silicone bits I can’t get off.

 

[beviking]

Thanks kveeti, that was very helpful!
But...won't the gravel behind essentially push the wall forward if the styrofoam and gravel in front of the wall are at the same height?

 

[beviking]

Like this side view....

 

[kveeti]

Yes, I'm sorry, I didn't give the whole picture. I was typing so much I wasn't thorough. I'm trying to find a site that my design is based on, because I'm not good at verbal descriptions. But of course I can't find the thing - yet. Anyhow, see if this makes sense. My styrofoam is 1 inch wider on the deep side of the wall. In this I am going to make a trench with a blade 1/2 inch deep. I am going to put in plexiglass strips (silicone them in). The rock wall really won't be holding anything up, it's just a decorative front.

 

[kveeti]

No sooner do I post then I find it. It's like the drawing halfway down, not quite, but you get the idea.

http://www.aquabotanic.com/dutchsecrets.htm

 

[RTR]

Silicone is a poor adhesive for rockwork. Its "hold" on such is time-limited underwater. I never use silicone for other than total non-pouous hard-finished materials such as glass. It is not even particularly useful for most plastics.

I would suggest using epoxy, and that you build your wall in staggered interlocked segments such that it can be lifted out in sections if needed.

EDIT: Well, I blew that one. I intended to say epoxy and typed silicone instead. Epoxy, epoxy, epoxy.

 

[kveeti]

Which reminds me, I also forgot to mention my wall pictured is actually in 3 sections, which fit together.

 

[beviking]

Got it Robert! Actually got it from the original linked thread kveeti mentioned. Oddly, you said the same thing then...?
Thanks kveeti, you've really been a help...as always. You're description was good, it just took me some time to figure it out.

 

[kveeti]

The rock wall won't be just decorative, it'll also reinforce the plexiglass, by leaning up against it. I will try to remember to take pictures as I'm setting the whole thing up. Then, 5 years down the road if it's still holding up, I can be more definitive. I wanted it that way also because then I can take each wall section out to clean it, if the need should arise, and the plexiglass will still hold.

I loved working with the putty. But, clean your fingers off every 2 or 3 joins. Once I waited until I was finished a whole section and it was very hard to clean off the big build-up on my fingers. For that one wall, it used a whole 4 ounce tube.