am i being a Sissy
 

Ok i have this rock work that weighs about 60lb, now i know are tanks holds thousands of pounds of water, i have a 150G . And i'll add sand and about 180 lb of rocks. But the sculpture i made has a "V" shape as you can see in the picture. I've built a support structure that is now failling and craking all over. That in mind i'm getting worried that the weight is too great on that one spot. If i cut the stands legs and put the structure directly on the sand, do you think its going to be ok, or just get rid of the whole feet all together and put the 16"X7" base rock directly on the glass be a better choice. 60Lb on an area 16"X7" is that too much for any glass. Any thoughs. Some of you must have done structure i'm waiting for your inputs thanks in advance. Maybe i'm over thinking this, just let me know.


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That's sweet

Consider drilling holes and using acrylic rod to hold together

I dont know if your joking but if you look at the picture thats exactly what i did actually nylon rods with nuts and further more its all cemented , the last one will have a stalactite comming down.

As long as the bottom glass of your tank is supported on plywood or similar you will be fine with that structure.

Charles

I'm on iPhone so pics small. I though the support was a PVC piece.
Would be better if it were hidden though

The rock will obviously weight a lot less in water, the weight of the water displaced can be subtracted from the rock weight to get the apparent. The density of rock varies but it's often not much heavier than the water itself. Actually recently seen a piece of rock float in a tank :neutral: So basically don't be concerned about the weight of your structure on the glass, it's also much stronger than the plastic PVC frame you built.

The structure you made looks awesome btw.

It will be hidden under 2 " of sand and the support right under the rock will be foamed and then sanded with resin epoxy. Nothing will show.

Thanks, i've got other sculptures on my thread , take a look; http://www.canreef.com/vbulletin/showthread.php?t=98466

Basile, I too am planning a custom rock sculpture in my build. I would suggest removing your pvc base and replacing it with 4 or 5 rock feet. I was planning to use all rock with a nylon or pvc skeleton as you have done.

Their's only one problem it doesn't solve the focused weight problem, the 60lb will be focused on these two rocks foot print. No , i've just got an idea, Lowes has pre-cut plexiglass that i can buy. Then i'll rebuild another support system with 1" pvc this time and still put eveything on a plexiglass who'll spread the total weight along its entire area of the panel and protecting the glass at the same time. Thanks for your inputs guys.:biggrin:

[quote=Basile;No , i've just got an idea, Lowes has pre-cut plexiglass that i can buy. Then i'll rebuild another support system with 1" pvc this time and still put eveything on a plexiglass who'll spread the total weight along its entire area of the panel and protecting the glass at the same time. Thanks for your inputs guys.:biggrin:[/QUOTE]
:thumb::idea::thumb:
I would buy the thickest plexiglass available to have a safe piece of mind.
Make sure all your PVC on the bottom is as straight a possible simply to disperse the weight equally...
I like your design..

Once you put your sand in will it not also help support that structure.I dont see any problems at all and wouldnt change a thing. Egg crate under the sandbed sucks though. It eventually get exposed and looks terrible once it does. I think your rockwork is cool. so to answer your question....just a little bit sissy:lol:

If you are using nylon rod, switch to acrylic and it will fix most of your problems. Nylon is not the best choice as it will begin to crack under the weight and will soften and swell in water.

Also, you can use physics to your advantage and add some weight on the opposite side from the overhang to reduce the torque (the bending force) on the rods. I did this on one of my old tanks and it worked like a charm. There are a few other things, like anchoring rods, that would also fix this and be easily hidden.

Photos shoot
 

So my sculpture is finished, just have to rebuild the support with 1" pvc which i got as you can see i just need elbows ,lol. Then just got to hide those nuts and put it in the tank with a plexi glass in the bottom. The sculpture is 36" longX20"wideX 20" hight. My tank is 21" hight, but the structure was suppose to be built with 1/2" pvc now its with 1" so my last rock will be floating, i'll put a mini palm tree and a lodge for the snails.

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At the end of the ramp a stalactite will come down.

Once again. Thats really cool. A frag plug will probably sit nice on those nylon bolts and whatever coral you choose will encrust over them.

LOL i've paid those custom made starfire tanks that i've been waiting for a while and i don't want anything to happen to them, i'll even phone the manufacturer tomorrow to discuss the Lb / sq inch those tanks can handle, to be sure. They, must know their product better than anybody lol. But thanks for the encouragements.