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.

Quote:

---

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.

Quote:

---

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.

I spend hours looking at all the different glues to fix a stone that broke a while back.

Ended up using this for several reasons.
-Strength
-Waterproof
-Adheres to damp surfaces (Its recommended to wet the stone when gluing)
-Fast curing - less than 30 minutes
-Expands slightly, filling any chips or small gaps.
Attachment 149665

Since then i have used it for a few damaged stones including a Coticule and gluing a wooden base to the back of a couple of jnats, all have turned out well

Quote:

---

Originally Posted by Brighty83

I spend hours looking at all the different glues to fix a stone that broke a while back.

Ended up using this for several reasons.
-Strength
-Waterproof
-Adheres to damp surfaces (Its recommended to wet the stone when gluing)
-Fast curing - less than 30 minutes
-Expands slightly, filling any chips or small gaps.
Attachment 149665

Since then i have used it for a few damaged stones including a Coticule and gluing a wooden base to the back of a couple of jnats, all have turned out well

---

this is a kind of polyurethane adhesive like Gorilla Glue, Kleiberit Pur ADHESIVE 501, Titebond #2300 Polyurethane Glue, etc.
all of them contain isocyanates that are not safe for health.

Quote:

---

Originally Posted by Nikolay

this is a kind of polyurethane adhesive like Gorilla Glue, Kleiberit Pur ADHESIVE 501, Titebond #2300 Polyurethane Glue, etc.
all of them contain isocyanates that are not safe for health.

---

Lucky i don't drink it then hehe :beer1:

Below are a few repairs..

The stone cracked on the corner :(
Attachment 149766

This cracked in the middle
Attachment 149767

This was glued to wood so it wouldn't crack. You can see in this pic how well it expands, kinda like a foam when its not clamped.
Attachment 149768

I have glued many Jnats to bases with gorilla glue and, no problems so far after years with a lot of use.

Quote:

---

Originally Posted by mainaman

I have glued many Jnats to bases with gorilla glue and, no problems so far after years with a lot of use.

---

PUR adhesives are safe when cured, but can cause allergic reaction and irritation on use.
In some cases it can cause isocyanate sensitization (chemical asthma).

Here it is MSDS for example: http://hybris.cms.henkel.com/henkel/...US&language=EN

Quote:

---

Originally Posted by Nikolay

PUR adhesives are safe when cured, but can cause allergic reaction and irritation on use.
In some cases it can cause isocyanate sensitization (chemical asthma).

Here it is MSDS for example: http://hybris.cms.henkel.com/henkel/...US&language=EN

---

What does that have to do with Gorilla glue?

Quote:

---

Originally Posted by mainaman

What does that have to do with Gorilla glue?

---

Easy answer; Tarzan & Gorilla glue both come from the jungle,,same stuff,,,:beer2:

I have used gorilla glue for the same application two or three times and it works really well.

If your hone is 50 yrs old then Stefan is correct, they would have used a resin obtained from pines, called rosin - the same stuff they use in powdered form on violin bows.

It becomes fluid on heating and solid when set. Water would not affect it. Some coticules are notorious for coming apart at natural cleavage lines, the types you see with thin black lines (la veinette) have already split in ancient times and the black (manganese dioxide aka pyrolusite) has flowed into the cracks.

Regards,
Neil

The real trick to adhesives is to select the right one for the application.

That is why I started this thread. As a handy-guy i have experience with nearly every concoction mentioned, but none with rocks. We all see here that there is no consensus on rocks.

It appears that everything will work, just depends upon what you're comfortable with and/or which advice one trusts to follow.

Personally, as the OP, I'm going to re-warm the original (resin)adhesive to see how it responds (as suggested by adrspach above, thanks that is information i likely wouldn't have found otherwise). The advantage of this method is that there's nothing to buy, and it's period-product correct.

If that doesn't work to suit me, I'll use a few dollops of JB gray, as it is "in house" and quite familiar to my paws.

cheers

It is realy about what suits you personally. At present I am trying to renovate few old Bailey planes and that for me means to find original japaning paint for it. On my significantly younger vice I just used nice hammered finish paint. As they say there are horses for courses.

Quote:

---

Originally Posted by adrspach

It is realy about what suits you personally. At present I am trying to renovate few old Bailey planes and that for me means to find original japaning paint for it. On my significantly younger vice I just used nice hammered finish paint. As they say there are horses for courses.

---

I just re-examined the stone, not enough rosin left. It got scrubbed away. And the blue is only 1/16 to 1/8" thick-PLUS i just don't need another variable in my honing learning at this point in time.

Arright, now as i get more edumacated about the coticule stones, I realize that I should have included photos or more better words to the OP here.

What i may have failed to put across is that there is blue belgian up "under" my coticule, THEN the slate backer. Such that I was considering cleaning the remaining glue off and flattening the blue side of the stone for shizits and giggles.

I talked me out of it already, but it was an option.