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Super glue & sand rock bonding technique

Anyone use the E Marco 400 kit?

Yes, it takes a while to cure (24 hours), but is very strong once it does.

Edit, this stuff can't be used wet in the tank, must cure outside of the water.
 
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I do want to mention there are three ways to do epoxy:

1) The purple stick you buy from LFS.
That is a combination of clay and epoxy that you mush together.
It crumbles, and it does not get into the pores of the rock well.
Generally very poor.

2) Quality liquid two part epoxy, mixed in with aragonite sand.
The liquid epoxy seeps deep into the rock, and not only holds it together, but makes the rock stronger.
The aragonite is mostly a filler, but it also makes it look like real rock, as in the super-glue + aragonite method.
The big problem is set time. You need to prop up the pieces in place, and let it set. Not something you can just hold.
People often use 30 minute epoxy. You put a few pieces together, let it set for an hour, and repeat.

3) Superglue + Epoxy.
First, you lightly superglue the rocks together. Just enough to hold.
Then you do the liquid epoxy + aragonite on all the joints, to make them last.
The problem is it can be hard to get to all the joints once the rock is together.
 
I do want to mention there are three ways to do epoxy:

1) The purple stick you buy from LFS.
That is a combination of clay and epoxy that you mush together.
It crumbles, and it does not get into the pores of the rock well.
Generally very poor.

2) Quality liquid two part epoxy, mixed in with aragonite sand.
The liquid epoxy seeps deep into the rock, and not only holds it together, but makes the rock stronger.
The aragonite is mostly a filler, but it also makes it look like real rock, as in the super-glue + aragonite method.
The big problem is set time. You need to prop up the pieces in place, and let it set. Not something you can just hold.
People often use 30 minute epoxy. You put a few pieces together, let it set for an hour, and repeat.

3) Superglue + Epoxy.
First, you lightly superglue the rocks together. Just enough to hold.
Then you do the liquid epoxy + aragonite on all the joints, to make them last.
The problem is it can be hard to get to all the joints once the rock is together.

for #2, two part liquid epoxy, it is feasible to mixed the 2 part, and use a syringe to inject the 2-part in the gap btw the rock? A section of my rock is not "secure" . Its in the tank, with coral attached. If i can inject the epoxy underwater, in the tank, that would be ideal. Its structurally stable as it is balance on its weight.
 
for #2, two part liquid epoxy, it is feasible to mixed the 2 part, and use a syringe to inject the 2-part in the gap btw the rock? A section of my rock is not "secure" . Its in the tank, with coral attached. If i can inject the epoxy underwater, in the tank, that would be ideal. Its structurally stable as it is balance on its weight.
So ... I would not recommend that.

Would it "work" : YES
Underwater epoxy repair is used a lot for concrete cracks, especially pools.
So you can buy kits like these easily: https://aquabondadhesives.com/underwater-repair-compound
Should cure fine and be structurally solid.

BUT : You need special epoxy. Do not just use something generic you get from a craft store.

The big question : Is it reef safe?
Once dry, pretty much all epoxies are reef safe. The concern is when you apply it wet.
Clearly SOME epoxies are reef safe applied wet, because we use those clay epoxy sticks at LFS.
But these specialty epoxies ... I really do not know.
I think what they add is some sort of gel to keep the epoxy from washing away and dissolving.
No idea what chemicals are in those.
And without knowing, I guess I would default to it being risky, so not advised.
 
Yes I used those (the Marco-400) to make my rockscape; bonding the various pieces with the mix. So far no problem; seems pretty strong. I also covered the junctions with sand so they're not noticeable. I might try this method (glue+sand) next time since it did take at least a day (I don't remember the exact length of time recommended) for the Marco mix to harden.
 
Several of my rocks structures broke apart during the move. Most of the breaks were not at the glued joints but a weak and porous point of the rock.
 
There are three rock junctions in this picture.
20230203_124654.jpg
 
Instead of pouring sand on, try baking soda. Look up "Baking soda and super glue"

"To create an even stronger and faster-curing bond, you can add baking soda to your super glue. When you mix super glue and baking soda, it accelerates the curing process. Chemically, the bicarbonate molecules in baking soda react with cyanoacrylate to create a reactive ion that more easily bonds with other cyanoacrylate molecules. These bonds establish long, polymer chains that are stronger and more resilient than cyanoacrylate-water bonding. The resultant substance is a super glue and baking soda plastic with a cement-like consistency that creates stronger, exceptionally durable bonds."

From https://info.aronalpha.net/blog/how...aking soda to your,create a more durable bond.
 
I've used that for non reefing projects.

The glue masters glue and sand cured quickly. By the time I finished the third layer of glue and sand on a joint, the first layer was strong enough to pick both rocks up by one side.
 
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