Thread: Natural stone separation from backer, repair?

I suppose I got the coticule too wet and the glue that held it to the slate backer turned loose.

Now I'm debating what exactly to do with it. Options I see:

Glue back as original.
Clean/flatten the blue side and try it out next time i hit a honewall.
Glue it to a board that fits the stone holder (coticule is too short). Or fit it to a board-unglued such that blue can be accessed..
Forget the other side, re-glue to slate, fix the whole shebang to board to fit holder.

What would you do?

Also, is there a preferred adhesive for this work?

For gluing stones I've used Loctite Professional epoxy and it worked great. Maybe too great. In one case I wanted to undo the bond and played hell getting the stones apart. Randy suggested the oven at 400 degrees and that did the trick after about an hour.

I'd probably opt to glue the coticule back to the original slate unless I could find a blue that was a match in size. If you ever want to sell it you'll probably have an easier time finding a buyer if the backing matches the coti whether it is blue or slate. Just IMHO.

I separated a Nakayama from its original wood base by putting it in a 250 degree oven for 30 minutes. It separated rather easily but I was worried about the stone temperature. It turned out OK.

I know people epoxy stones to wooden bases. Ive epoxied a couple thin Jnats I bought. I use marine epoxy and had 1 inch inch granite cut for it. Wood isnt a good choice as water will make it expand and contract. The egyptians used cedar to split large granite blocks by inserting wooden beams in a trough carved in it and wetting the wood and the wood expansion cracked the granite. I will take granite over it anytime. And for 4 scraps cut for 20 bucks you cant go wrong.

It happens with Coticules quite a bit, not sure why. Even with natural combos. I use Devcon 5 minute epoxy. They never come back apart...I also use the same stuff in work. I mix it together on a paper or plastic plate and use an acid brush to apply. Works great...!

JB Weld will work, as will any good two-part epoxy.

Stay away from Gorilla Glue, as it expands as it cures.

Granite scraps, interesting. maybe next time i'm down at BigCity I'll look for some.

This stone is easily 50 years old, came from a barber-who only refreshed on it. I just forgot it was in the water.

I'll reassemble as OEM, and stick that onto something--it has been a bit of a chore going from big easy 8x3's down to this one. Gotta fix me up a hone-plank as seen here recently.

Originally Posted by zib

It happens with Coticules quite a bit, not sure why. Even with natural combos....

I'm betting it's because the Belgians used water-soluble adhesive (or one that expires after 30-40 years). As, it fell apart after a soaking. No, i didn't say i intentionally soaked it. But it got soaked.

I have epoxies, just haven't glued rocks before.


thanks.

I've never glued stones, but whenever I want something to stay glued together, I use 3M 5200, let sit for 24 hours, never had anything that I glued with it seperate.

Originally Posted by JimmyHAD

For gluing stones I've used Loctite Professional epoxy and it worked great. Maybe too great. In one case I wanted to undo the bond and played hell getting the stones apart. Randy suggested the oven at 400 degrees and that did the trick after about an hour.

I'd probably opt to glue the coticule back to the original slate unless I could find a blue that was a match in size. If you ever want to sell it you'll probably have an easier time finding a buyer if the backing matches the coti whether it is blue or slate. Just IMHO.

Once you put the stone on the epoxy you have a little chance to unglue it.
It is too hard to be easily removed with knife or chisel.
The decomposition temperature of epoxy is about 450С ( 850 F). And when it decompose it smells like hell. So don't try to do it at home.

If your stone is natural you are at risk to loose it once baked to such a temperature.

That's why I'd prefer to use contact glue like 3M 77 or sealing compound like MSA-polymer or acrylic water based construction adhesives.

Recently I had to reglue few cotis and as they were originally glued with pitch resin I just needed to reheat both sides to get the glue plastic again and put the bits together.