coti glue gave up
- Thread starter kayvee
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Yea, clean off old glue, lap smooth. Use any waterproof or water-resistant glue. There is not much shear strength needed so most glues will work. I have used CA, Silicone, and E6000 with good results.
Apply a thin coat on each side and sparingly near the edges so you do not have a lot of squeeze out. If using CA use a gel CA.
You can use epoxy but probably over kill and messy.
Apply a thin coat on each side and sparingly near the edges so you do not have a lot of squeeze out. If using CA use a gel CA.
You can use epoxy but probably over kill and messy.
I just did this. I used a 2 part epoxy with a 5 minute set. Scraped off the old glue, cleaned and put it back together. Then lapped the sides clean.
Epoxy
Or if you're really old school, resin like they woud use in the old days.
timwcic
"Look what I found"
Epoxy
www.badgerandblade.com
Fixing A Broken Coticule
This was found at the flea market a few weeks ago. At first thought is was two broken Coti's until I got home. Put the two pieces together and they become one. Can not let a wavy natural remain in this state. A while ago, I rescued a BBW that lost its coticule. Seller told me the yellow part...
www.badgerandblade.com
This happened to me a couple of years back.
I used a 400 grit diamond plate to clean both of the separated sides then added glue.
The only glue I had was super glue and I splurged on way too much.
The glue squeezed out the sides of the stone gluing it instantly to my kitchen counter top at the bottom and to my fingertips at the top.
I used a scraper and eventually removed the superglued coticule from the kitchen counter leaving ridges of glue behind, much to my girlfriend’s consternation, but the coticule layer now sat slightly askew on it bbw slate counterpart.
In short it was all a bit of a disaster and I was lucky to be left with a usable coticule at the end of it.
Moral of the story: if you use superglue use it very sparingly and with extreme caution.
I used a 400 grit diamond plate to clean both of the separated sides then added glue.
The only glue I had was super glue and I splurged on way too much.
The glue squeezed out the sides of the stone gluing it instantly to my kitchen counter top at the bottom and to my fingertips at the top.
I used a scraper and eventually removed the superglued coticule from the kitchen counter leaving ridges of glue behind, much to my girlfriend’s consternation, but the coticule layer now sat slightly askew on it bbw slate counterpart.
In short it was all a bit of a disaster and I was lucky to be left with a usable coticule at the end of it.
Moral of the story: if you use superglue use it very sparingly and with extreme caution.
I use CA glue to fill smsll fissures. I use 5 min two part epoxy for gluing combos together.
I had one go recently at a fissure running through the middle of the BBW side. Epoxy, then some CA into the sides to seal the crack.
I would recommend the loktite construction super glue. It's a gel but it wiped off the edges pretty easily the few spots a drop came out. If you keep a thin bead when applying it and stay ½" from all the edges it shouldn't bleed. Use wood on either side for protection and stick it in a c- clamp.
Was it the thin stuff or the gel? Everyone says don't use the gel but I've had really good luck for this specific purpose.
The 5 minute Epoxy I use is Devcon - I have used other epoxies for different work, but for gluing stones together the Devcon works very well. I usually clamp lightly to cause some squeeze-out so the seam is continuous all around.
I don't like gluing large areas with CA, esp when the material might take a knock or bump - the stuff has a tendency to let go under that sort of duress. I will use CA to fill a crack, with a drop fill technique. I never use baking soda as an accelerant when doing that, the heat generated can be both significant and problematic. A fill should be dimensionally stable, and not intensely exothermic.
I don't like gluing large areas with CA, esp when the material might take a knock or bump - the stuff has a tendency to let go under that sort of duress. I will use CA to fill a crack, with a drop fill technique. I never use baking soda as an accelerant when doing that, the heat generated can be both significant and problematic. A fill should be dimensionally stable, and not intensely exothermic.
Here is an interesting video by Gordon Addison. Gordon makes seamless repairs to antique Rosewood hand plane totes, (handles). Rosewood is an oily wood, that now days is almost impossible to obtain new, and why he has built a months long waiting list business making these repairs.
Most folks believe that epoxy is needed for these difficult repairs, and Gordon uses epoxy frequently, but decided to test several glues and have a proper laboratory test all the samples to failure.
The results were surprising, especially plain old Tightbond, yellow woodworking glue, Hide Glue and Gorilla Glue polyurethane.
While he is not gluing coticules, the results are interesting and most glue are much stronger than folks think. There really is not a lot of testing and a lot of myths and “advertising” hype with all glue usage.
Sticking 2 stones together does not require a super strong epoxy, but it will work fine if a bit messy.
It is also surprising that antique pine resin glued coticules have remained glued all these years banging around.
(Testing glue on Brazilian Rosewood)
Most folks believe that epoxy is needed for these difficult repairs, and Gordon uses epoxy frequently, but decided to test several glues and have a proper laboratory test all the samples to failure.
The results were surprising, especially plain old Tightbond, yellow woodworking glue, Hide Glue and Gorilla Glue polyurethane.
While he is not gluing coticules, the results are interesting and most glue are much stronger than folks think. There really is not a lot of testing and a lot of myths and “advertising” hype with all glue usage.
Sticking 2 stones together does not require a super strong epoxy, but it will work fine if a bit messy.
It is also surprising that antique pine resin glued coticules have remained glued all these years banging around.
(Testing glue on Brazilian Rosewood)
It's not really all that messy. You can literally do all of this on top of a flap of a cardboard box, use another flap to scrape the overrun/put it on the flats and two rubber gloves in the end you end up with some cardboard with cured epoxy on it, a coticule with a thin film of epoxy on the sides you can lap off quickly, some gloves to toss and pretty much nothing else. It beats CA to hell where one wrong move and you are glued to whatever you are doing till you get the acetone out. As far as the test goes it is more a good test for his application. If I were making an acoustic guitar out of Brazilian rosewood for example I would probably never use anything other than fish glue or hide glue and probably go with fish for longer open time just because IDK what will happen years down the line and someone might have to get a fretboard off or a neck out for a reset or deal with braces or whatever. If someone snapped a headstock off though, I would probably go with titebond for the repair and splines though.
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timwcic
"Look what I found"
I agree is not messy at all. A thin layer on all surfaces. I use spring clamps to put pressure after mating the two surfaces together while using newspaper covering the work surface. Popsicles sticks to scrape any epoxy that squeezes out. And I do want overrun around the whole perimeter so completely sealed. Any thin coverage remaining laps off very easily during cleanup along with any newspaper that might have also stuck. I do prefer using slow cure, one hour, epoxy so any misalignment can be corrected. If stones have any big gaps, I will add coticule dust to the epoxy so the visible repair blends in. Like most thing in this endeavor, keep it simple and don’t overthink
Epoxy Is only messy if you’re sloppy, and if you’re sloppy then CA is the last thing to be using.
Been doing this a long while, have repaired many dozens of split stones, and created many synth combos, fixed a boatload of nagura, etc.
I stick with epoxy because after doing it so many times its proven itself to be a better choice. Working time is good, setup time is good, the bond is beyond reproach.
Im not basing my choice on a video made by someone else doing something else. I figured this out buy fixing stones myself, trying many adhesives, etc, over the last 10-12 years.
Thete are many ways to glue things, and many adhesives to choose from. Some work better than others for some tasks and repeatedly, epoxy has been my choice for re-lamonating stones.
Typically, CA’s shear strength is poor., epoxy is much better in that regard and its the main resson making it my go-to for this work. Epoxy handles vibrations, bumps, knocks, temps, gsps, etc, better..
Been doing this a long while, have repaired many dozens of split stones, and created many synth combos, fixed a boatload of nagura, etc.
I stick with epoxy because after doing it so many times its proven itself to be a better choice. Working time is good, setup time is good, the bond is beyond reproach.
Im not basing my choice on a video made by someone else doing something else. I figured this out buy fixing stones myself, trying many adhesives, etc, over the last 10-12 years.
Thete are many ways to glue things, and many adhesives to choose from. Some work better than others for some tasks and repeatedly, epoxy has been my choice for re-lamonating stones.
Typically, CA’s shear strength is poor., epoxy is much better in that regard and its the main resson making it my go-to for this work. Epoxy handles vibrations, bumps, knocks, temps, gsps, etc, better..
- Thread starter
- #17
Which brand do you use? Most I've seen promote fast setting, 5 minute epoxy
I have used devcon 2 ton slower cure when it was what I had and it worked fine. Thing is the incremental gain in strength of bond really doesn't matter with a hone. The stone would probably shear before you hit the limits of the fast or slow cure.
timwcic
"Look what I found"
I get all my epoxy adhesives from a local company that caters to the marine industry. Any readily available two part, such as Devcon would work just fine. Five minute will work with plenty of working time. I like slow cure in case I screw up and need to make adjustments
If I am doing knife scales, I’ll use West Systems 105 or Gflex. Marine grade, Slow cure. I’ve used them for stones too, when I difnt have Devcon 5 min but the cost isn’t justified.
The slow set epoxies are technically better And “marine grade” slow set would be top tier, on paper. But it becomes “diminishing returns” time quickly. FWIW Ive used the 5 min stuff to set knife handles too, worked fine, still going strong. Cost vs application is a big component in choice for me. The Devcon 5min in syringe is under $10. West systems stuff runs 2-3x more usually.
The slow set epoxies are technically better And “marine grade” slow set would be top tier, on paper. But it becomes “diminishing returns” time quickly. FWIW Ive used the 5 min stuff to set knife handles too, worked fine, still going strong. Cost vs application is a big component in choice for me. The Devcon 5min in syringe is under $10. West systems stuff runs 2-3x more usually.
