DIY Rocks for new aquascape

[JCOLE]

Hello everyone! I am in the process of resetting my 480 gallon peninsula system. I am setting the system up to be a "traditional" system (front viewing) instead of a peninsula. I am looking to create my own aquascape using DIY rocks. I have all the materials and have practiced creating some rocks already. I believe I have the process down now, but I would like a little help with making the molds. See picture below. This is the top down view of the rockwork that I am thinking about creating. The tank is 8'x4'x2'. I would like to make this structure and only have the maximum height of a foot at it's tallest points. The rocks will be hollow throughout as I plan on running plumbing through the rock work to have flow in random locations of the rocks. It will be a closed loop through the rock work but without it leaving the tank. I do not want to have bulkheads on the bottom. I am thinking of putting a DC pump in the back left and right corners of the rock work for the flow.

Or thinking of this layout: flow as the same as above

I was planning on putting some bricks, etc in place for the base, then putting chicken wire over the bricks in the form the structure of the rock work. I will then cover the chicken wire with plastic and put the cement on the plastic. In theory, it shouldn't stick to the plastic, and I could just lift the rock work up from the molds.

Does anyone else have any other ideas for creating the mold? I was also thinking of using spray foam and covering that with plastic once it dries. I am also thinking of vacuum sealing the plastic against the mold to create a tight fit for the concrete.

Any help or ideas would be greatly appreciated.

Thanks everyone!
Josh

 

[griss]

I'm terrible with this stuff but wanted to chime in to follow along.

 

[JCOLE]

I'm terrible with this stuff but wanted to chime in to follow along.

Me too! I think I have a good idea on what I am looking to do. I think once I start molding with the chicken wire, then things will hopefully start falling into place.

 

[Reefing102]

I believe @Paul B has made rock using PVC.

I know in the past people used to use totes full of moistened sand and sculpt a structure out of that. That won’t really work with your hollow structure thought though.

 

[JCOLE]

I believe @Paul B has made rock using PVC.

I know in the past people used to use totes full of moistened sand and sculpt a structure out of that. That won’t really work with your hollow structure thought though.

Yeah, I have seen that. I used the sand and it does work really well. Just looking to build a larger mold that could hold a little weight without it breaking apart. I am thinking of taking some cardboard boxes and roughing them up and then putting the chicken wire over that to create the layout.

 

[kharmaguru]

Some ideas for forming molds might be using drywall compound covered in saran wrap (for the release). Durabond 90 sets like concrete. You could also use automotive bondo but it's more expensive. Obviously you would need a wood substructure and then make your contours with the drywall compound. I also like your sprayfoam idea but you would need alot and again it would end up being expensive. Just some thoughts, maybe I'm way off.

 

[Misled]

How about using cardboard paper towel rolls to give you openings through the rocks leave room to get them or some acid washing to clean then. I used acrylic rods and plastic to give ming extra support.

 

[JCOLE]

Some ideas for forming molds might be using drywall compound covered in saran wrap (for the release). Durabond 90 sets like concrete. You could also use automotive bondo but it's more expensive. Obviously you would need a wood substructure and then make your contours with the drywall compound. I also like your sprayfoam idea but you would need alot and again it would end up being expensive. Just some thoughts, maybe I'm way off.

That is a good idea! The Saran wrap is so I can remove the cement from the drywall compound, correct? I could use the box idea and chicken wire to form the structure, and then use the compound to layout the area for the cement. I wonder if the drywall compound will hold on the chicken wire? If not, what do you think could be a better substitute for the chicken wire?

 

[JCOLE]

How about using cardboard paper towel rolls to give you openings through the rocks leave room to get them or some acid washing to clean then. I used acrylic rods and plastic to give ming extra support.

That is a good idea! I plan on running 1" pvc through it at random spots anyways for bulkheads, so why not throw some towel rolls in as well.

 

[kharmaguru]

That is a good idea! The Saran wrap is so I can remove the cement from the drywall compound, correct? I could use the box idea and chicken wire to form the structure, and then use the compound to layout the area for the cement. I wonder if the drywall compound will hold on the chicken wire? If not, what do you think could be a better substitute for the chicken wire?

Affirmative on the saran wrap. I'm sure wax or parchement paper would work too. The durabond products (you can go as low as 20 minute set times I believe) has resin in it and sets very hard and will definitely bond to chicken wire. It's a powder so you can mix it as stiff as you want. Don't picture typical soft delicate drywall compound, you can use this stuff as concrete patch. My suggestion was with the traditional idea of a mold - something you pour your mixture into and then remove your mold once things set to reveal your finished product. Is this what you are attempting or are you talking about a support structure that stays as part of the finished product?

 

[JCOLE]

Perfect. I will check into Durabond as well.

I am looking to build up a support structure in the layout of my rockwork. I will then put plastic over it and pour the cement. This way, I can remove the cement, and it will be hollow inside. See link below. This is what I am going to do, but instead of bricks, I am thinking of using cardboard boxes. I was just thinking of something I could use instead of the chicken wire and boxes. Although this might be my best option.

Faking It: The Artificial Reef

By Simon Garratt I will say right now that I have absolutely no intention whatsoever of shouting about how we should all be making our reefs out of fake live r

reefs.com

 

[kharmaguru]

Perfect. I will check into Durabond as well.

I am looking to build up a support structure in the layout of my rockwork. I will then put plastic over it and pour the cement. This way, I can remove the cement, and it will be hollow inside. See link below. This is what I am going to do, but instead of bricks, I am thinking of using cardboard boxes. I was just thinking of something I could use instead of the chicken wire and boxes. Although this might be my best option.

Faking It: The Artificial Reef

By Simon Garratt I will say right now that I have absolutely no intention whatsoever of shouting about how we should all be making our reefs out of fake live r

reefs.com

View attachment 32400611
View attachment 32400612

Gotcha. 2x4's, D-90 and clingwrap sounds cheap and easily configurable to me.

 

[JCOLE]

Gotcha. 2x4's, D-90 and clingwrap sounds cheap and easily configurable to me.

I picked up some bricks and D90 last night. After thinking about it some 2x4s or 2x2s would be a great option. I picked up a sheet of 8x4 plywood as thats the same dimensions as the tank. With the 2x4s then I could build the foundation and screw them to the plywood. Lay the chicken wire over the 2x4s to build the rock formation. Thinking of putting duct tape over the chicken wire for added strength and then adding the D90. I am really liking this idea and it should allow me to make adjustments as needed.

Thanks for the recommendation. This is exactly what I was hoping for.

 

[JCOLE]

@kharmaguru also, they didn't have Durabond 90 at the Lowes near me so I picked this up instead. Do you think this should work or do you still recommend the D90? I can get the D90 but it will have to wait until next week which I am good with.

https://www.lowes.com/pd/ProForm-Quick-Set-Lite-18-lb-Lightweight-Drywall-Joint-Compound/1002063842?cm_mmc=shp-_-b-_-prd-_-pro-_-ggl-_-LIA_BDM_000_PRO-_-1002063842-_-local-_-0-_-0&gad_source=1&gclid=CjwKCAjwxLKxBhA7EiwAXO0R0K4noMUvyq6KAV8HDy8hptS6orFhss51uOf2zb3XWosnfcBHXcAWrhoCzuYQAvD_BwE&gclsrc=aw.ds

 

[kharmaguru]

@kharmaguru also, they didn't have Durabond 90 at the Lowes near me so I picked this up instead. Do you think this should work or do you still recommend the D90? I can get the D90 but it will have to wait until next week which I am good with.

https://www.lowes.com/pd/ProForm-Quick-Set-Lite-18-lb-Lightweight-Drywall-Joint-Compound/1002063842?cm_mmc=shp-_-b-_-prd-_-pro-_-ggl-_-LIA_BDM_000_PRO-_-1002063842-_-local-_-0-_-0&gad_source=1&gclid=CjwKCAjwxLKxBhA7EiwAXO0R0K4noMUvyq6KAV8HDy8hptS6orFhss51uOf2zb3XWosnfcBHXcAWrhoCzuYQAvD_BwE&gclsrc=aw.ds

I've never used that specific one but anything fast setting is a resin cure and should set hard. I've used d90 and sheetrock 90, and although s90 is a bit softer after cure, they are both way harder than general purpose compound. I think you'll be fine.

 

[kharmaguru]

A couple thoughts about this plan. If you're using 1 inch chicken wire, I would do a couple layers offset to make the gaps smaller. Make the 90 really stiff (less water) but don't try to fill the holes or you'll just push it all through. I would build it up over a couple passes. It bonds very well to itself. The beauty is it will be sandable after should you want to get fussy.

 

[JCOLE]

A couple thoughts about this plan. If you're using 1 inch chicken wire, I would do a couple layers offset to make the gaps smaller. Make the 90 really stiff (less water) but don't try to fill the holes or you'll just push it all through. I would build it up over a couple passes. It bonds very well to itself. The beauty is it will be sandable after should you want to get fussy.

Well I plan to get fussy so the sanding is what I like about it I like that I can continue to add, sand, add more later, sand, etc until it is where I wanted it.

Yes, the wire is the 1" kind. Instead of adding more layers of chicken wire I was planning on layering the wire with duct tape then adding the compound on top of the duct tape. Do you think that would work instead of layering the wire?

 

[JCOLE]

I've never used that specific one but anything fast setting is a resin cure and should set hard. I've used d90 and sheetrock 90, and although s90 is a bit softer after cure, they are both way harder than general purpose compound. I think you'll be fine.

Ok. I'll use this one and if there is an issue then I'll look into the D90.

 

[kharmaguru]

Do you think that would work instead of layering the wire?

yep.

If this experiment works, you can do a tutorial.

 

[JCOLE]

yep.

If this experiment works, you can do a tutorial.

Probably be a lot of "what not to do".