# Question: how do you glue / epoxy knife scales on ? Mine fell off



## coloradoclimber (Apr 7, 2007)

I bought some fixed blade knife kits from Woodcraft to make for Christmas. The "kit" is really just the blade, I have to add the scales and rivets.

I cut the wood for the scales, sanded the inside, sanded the blade tang, cleaned both the scale and the tang with acetone, mixed some two part epoxy, spread a thin uniform coat, then clamped for 24 hours.

I got the scales thinned to the thickness I wanted and was starting to shape them when the first scale popped off. I checked the other side and sure enough I could see the other scale was coming loose too, a quick poke with a pocket knife under the scale and it popped off too. I checked the others and I could see that at least 3 more were starting to pull loose. I tested them with a pocket knife and they popped off with a little prying. They probably would have held in place for a while but likely would have come off eventually.

So, now what? I've already shaped the scales and I would like to use them. I can epoxy them back on but I'm not sure what went wrong the first time. I made 4 knives, the first has wenge scales and those seem to be staying on. Two have cocobolo and 3 of those 4 scales are off. The last was chakte viga, that's the one that popped both scales off first.

I thought maybe it was the wood, that the epoxy was not sticking to the wood because of some oils or something but when the scales popped off all of the epoxy was attached to the scale and almost none on the tang.

Next I'm thinking maybe it is because of moisture content in the wood. I cut the cocobolo and chakte scales from wax covered turning blocks. The wenge I had laying around the shop for a year or so. I did not let the scales sit very long before gluing them. Maybe a couple days Definitely the cocoblolo and chakte scales seem to have a higher moisture content than the wenge. At least they rasp much cleaner without much tearout. I don't know if that is a property of the wood or moisture.

I've already sent a PM to Mark DeCou, it looks like he's gone down this path more than once.

So what else should I do? How do you glue on knife scales and any suggestion on whether it could be the wood or moisture?

Thanks


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## dkg (Dec 14, 2009)

I do not think that moisture or or the wood is a problem. It might be the epoxy. I have used West epoxy for quite some time. When joing wood, I use the 207 part B because it is compatable with different finishes. I also use a powder adhesive mixed in with the mixed part A and part B. I mix the adhesive until a get a cool wihip consistency. You have about 20 minutes to work with the stuff.


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## TopamaxSurvivor (May 2, 2008)

Let us know what you find out. I haven't done this yet, but am planning to give it a try. thx.


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## coloradoclimber (Apr 7, 2007)

Thanks for the replies. I guess I'm gonna give a different epoxy a try. I used a 2 part slow set from Walmart, I guess that should have been my first clue 

I did try roughing up both the scale and the tang. I rubbed both on 100 grit sand paper on a flat surface. Mostly to flatten them, remove any burrs, and rough them up a little.

I did wipe both the tang and the scale with acetone before applying the the epoxy, maybe 15 minutes or so before applying the epoxy.

I'll see if I can hit Rockler tomorrow and pick up some West Systems. If I cant find any I'll look for the Raka.

I'll post back after I get them re-epoxied and give them a chance to work or fail.


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## Tangle (Jul 21, 2007)

I did the 2 knives in my projects with two part epoxy that comes in the syringe type tubes. I don't think I clamped it very long but I did make sure it was in the pin holes as well as on the steel and wood. I don't think I sanded the back of the scales any at all. I carry the folder in my pants and have carried the belt knife as well. I think it must be the glue.


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## papadan (Mar 6, 2009)

My guess would be the epoxy you used. I have used the slow setting and 5 minute types to put golf club heads on, always a steel shaft and heads of wood and metal. Never had one come loose. Don't know the brands off hand, usually buy it at the borgs. You stated that most of the epoxy stuck to the wood and not the metal, so that rules out problems like oils in the woods.


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## coloradoclimber (Apr 7, 2007)

Hmmmm, Dave you might be onto something.

I thought maybe I might have clamped them too hard, as in "I squeezed the hell out of it".

I had three jorgensen bar clamps per knife handle and I had them cranked down pretty much as hard as I could screw them down, seriously cranked. I figured the tang was flat, the scale was flat, I didn't want a big seam of epoxy showing so squeeze it till the seam pretty much disappeared. Maybe too much . I'll get some better epoxy and maybe go a little bit gentler on it on the re-glue. thanks for the ideas


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## coloradoclimber (Apr 7, 2007)

Well that makes sense too. I give that a try, maybe rout / dremel some grooves in the scale so I can keep some registration surfaces but still add in some volume for the epoxy.

That's why this is such a great site. Lots of good ideas and good people quick to share.


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## interpim (Dec 6, 2008)

I have had real oily woods not take epoxy before…

I was using a decent quality epoxy too. I noticed that when the epoxy heated as it cured it pulled the oil to the surface that was being glued and ended up pushing the epoxy away from that surface.


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## TopamaxSurvivor (May 2, 2008)

Do you know what brand the Walmart epoxy is?


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## coloradoclimber (Apr 7, 2007)

The Walmart epoxy comes in two side by side syringes and has "2 Ton Clear Weld Epoxy" written on it, made by ITW Performance Polymers, Riviera Beach, FL.

Another thing I noticed. The epoxy did not stick to the tang at all. Even where there was squeeze out in front of the scale on the the blade. I picked at the squeeze out with the tip of my pocket knife and it flaked right off the steel.

So I'm not sure what is going on with the epoxy bond, or lack of bond, to the tang. I'm going to try to rough up the tang a little extra, make sure I clean it well with acetone, and try some "better" epoxy.


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## roman (Sep 28, 2007)

do u hav a picture?


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## JohnGray (Oct 6, 2007)

Picture? Did you pin it too or just use epoxy? What kind of wood did you use?


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## coloradoclimber (Apr 7, 2007)

The handles are drilled for pins and a lanyard, but I did not put the pins in yet. I wanted to shape the handles with a rasp first, then glue the pins in, then hit it with a final pass over the spindle sander.

The woods are Wenge, Cocobolo, and Chakte Viga. The wenge seems to be holding strong, the chakte popped right off, and I had to pry a little bit to get the cocobolo off, but it was already starting to pull away from the steel.

Here are some pictures of the scales after coming loose. The first two are of the Chakte, they pulled away perfectly clean, not a bit of epoxy stuck to the tang. The cocobolo left some epoxy behind but a good portion was unstuck. The last picture is of the pins and lanyard tube to be installed after I finish getting the handles rough shaped.

You can see the epoxy squeeze out at the top of the handle where it just came right off of the steel. I did wipe down the steel with acetone before putting on the epoxy.


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## TopamaxSurvivor (May 2, 2008)

I have never had epoxy fail to stick to metal. Never heard of it before, but I think I'll avoid "2Ton epoxy" )


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## Ger21 (Oct 29, 2009)

You must have still had a film of some sort on the steel for it not to stick. One other thing you can do, with the thinner epoxies mentioned, is to wet sand it into the steel with 60 or 80 grit sandpaper. You can do this to the wood as well. West System recommends it for a better bond.


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## MOJOE (Jun 13, 2009)

you might try to "rough up" both the tang and the scales prior to placing the epoxy. That will give it something to bite in to. also, i think cocobolo tend to be a little oily…..might have something to do with it.


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## decoustudio (May 4, 2006)

I sent you an email with my opinon on the solution.

m


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## decoustudio (May 4, 2006)

I've not had trouble with any of these woods, using any type of epoxy. But, it does not bond well to metal. I use peened head rivets to hold on the scales. For metal adhesion, I recommend JB Weld, or F26 glue might be a solution.


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## coloradoclimber (Apr 7, 2007)

Mark, thanks for the PM. And thanks everyone else for the suggestions.

I'm leaning toward some / all of the fault being mine.

I decided to do a little more research now that 6 of the 8 scales have failed. I looked into getting some West System but the only place around here that has it is Rocker which is 50 miles away, each way, and only has it in quart sizes, so I end up with a half gallon of epoxy at $85 USD. Too far away, too much epoxy, too much money.

Woodcraft carries a product called T-88 Structural Epoxy Adhesive by System Three. Woodcraft is 12 miles away, has it in a half pint size, and it costs $17.50 USD. All three a better fit for me.

System Three has a free PDF book called appropriately The Epoxy Book. In the section on techniques of epoxy use they have a bullet point:

"Third, do not over-clamp. Epoxy resins require only contact pressure.
Over-clamping can squeeze most of the adhesive out of the
glue joint and the epoxy that is left is absorbed into the wood
starving the joint. A glue-starved joint is very weak. Use only
enough pressure to hold the joint immobile and keep the two
surfaces in contact until the epoxy has set overnight at normal
temperatures. Nails, screws, clamps, rubber bands, or staples can
all be utilized.. Clamp just hard enough to close up the joint."

And as I state above. I *OVER CLAMPED* the scales pretty hard. I put 3 Jorgensen bar clamps per handle, 3 was about all I could fit, and I CRANKED them down, hard. I was going for a near invisible handle to tang glue joint and I got it. The joint was paper thin or less. Pretty much you couldn't even see the glue joint before the scales popped off. That's how I cold tell the other scales were going bad. I could see a hairline joint at the scale to tang surface.

So at this point I'm willing to believe some (or most) of the fault lies with me. I'll be trying again tomorrow with the following procedure:

- Rough the tangs a bit more aggressively. Maybe hit them a stoke or two with a bench grinder, or maybe just a bit more aggressive on some 100 grit sandpaper.
- Dremel some shallow grooves in the back sides of the scales to hold a bit more epoxy. 
- Rough up the scales on some 100 grit sand paper. 
- Wash both the scale and tang with acetone.
- Use better epoxy.
- Clamp the *much* more gently.

And we'll see what round two brings. I'll update on the success or failure of this new attempt.


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## Ger21 (Oct 29, 2009)

Just to clarify, with the West System, you won't get a half gallon. The resin is a quart, but the hardener is only about 1/2 pint, as the ratio is roughly 5:1. The resin and hardener at Rocker is about $55 for both, + the pumps.

Also, West System has surface prep info specific to materials.
http://www.westsystem.com/ss/surface-preparation/


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## toddhelmkamp (Dec 29, 2009)

I think you're on the right track. Over clamping is a big problem with epoxies. Honestly, I've used epoxies and I don't really care for them. I've been using Gorilla Glue, which is a polyurethane. Honestly, I've *tried* to break scales off when I used Gorilla Glue and have had a hard time. A little bit goes a long way though, as it expands as it cures. I like it for wood-to-metal bonds. You want to clamp the scales hard with it though, because as it expands it will actually expand into the pores of the wood. I use the white 1-hour fast cure type. Don't use the super glue, its completely different. I've used the Gorilla Glue successfully on about 15 knives now with no problems.

For a discussion of different adhesives for knifemaking, check out this article by Pat over at Northcoast Knives:

http://northcoastknives.com/northcoast_knives_tutorials_hints_tips15.htm

Good luck!


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## TopamaxSurvivor (May 2, 2008)

Those sources seem a bit spendy if you're just dong a few. I have always had good luck using Locktite brand epoxy.


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## toddhelmkamp (Dec 29, 2009)

That's another reason I love Gorilla Glue. $5 a bottle, and a bottle will do many knives.


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## coloradoclimber (Apr 7, 2007)

I got the scales epoxied back on. I ended up using the T88. I put the lanyard tube and two of the scale pins in to line up the scales. I mixed a fresh batch of epoxy for each knife, smeared a good coat on the tang and scale, coated the pin holes and pins, put it all together, wrapped it in wax paper, and used rubber bands to hold it together to cure. Here is what a couple of them looked like coming out of the wax paper after 24 hours.


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## toddhelmkamp (Dec 29, 2009)

Lookin' good. I too would like to see them when you're done!


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## coloradoclimber (Apr 7, 2007)

Making some progress on the handles. Got all the epoxy rasped and sanded off. Got the pins and lanyard tube cut off and sanded down. The other pin hoes are drilled out. Still need to cut the rest of the pins, fit them, and glue them. Then the final shaping and finishing. So far the new epoxy and gluing technique is holding strong. More epoxy and less clamping force seems to be the watch words.

Here's what they look like so far.

Chakte Viga









Wenge









Cocobolo


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## toddhelmkamp (Dec 29, 2009)

Beautiful! What will you use to finish them?


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## coloradoclimber (Apr 7, 2007)

yeah, I'm a lot happier now. It looks like things are going to hold together this time. I still have a bit of work to get them finished but I feel better about the glue up.

They are gonna be a little late for Christmas presents but I usually only hit about 50/50 on time delivery for home made Christmas and birthday presents anyhow. People who get gifts from me have come to expect it 

Thanks again to everyone who chipped in on the epoxy problem. It's good to have people to bounce ideas around.


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## coloradoclimber (Apr 7, 2007)

Todd, good question, unfortunately I don't yet have a good answer.

This is my first attempt at putting together a knife and I have not thought that far ahead. Any suggestions? I probably would have ended up with my old standby, soak in tung oil, let cure, and then maybe a coat of poly for some durability?

I could shellac, buff, and wax. The chakte and cocobolo seem to have enough oils and wood density that a buff and wax would probably create a deep shine. The wenge is probably going to require something more. I'll probably oil the wenge then maybe try to buff and wax.

Since this is something expected to be handled and probably have a sheath strap around the handle it seems like it needs to be a durable or penetrating finish. I'll do a little more internet research and see if I stumble across any specific finishing tips. Or maybe I'll post another question on LumberJocks "How do you finish your knife handles?". Thanks again.


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## toddhelmkamp (Dec 29, 2009)

Tung oil is really good to use. It will sink in and harden somewhat. I recently started using a three-step finish from Dem-Bart. It starts with a few coats of oil, then a sealer, and then a light wax. I bought it from Jantz Supply (jantzsupply.com) I'm really happy with it. You can also try Birchwood-Casey Tru-Oil, that works too.


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## SteveCo (Jan 1, 2010)

You've inspired me to try my hand at knife making, we have a local woodcrafters and I have seen some of the kits. I am new here, this is a wonderful place to get inspiration and ideas.
Thanks


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## toddhelmkamp (Dec 29, 2009)

Hi Steve, and welcome! I love knifemaking. Soon I hope to make my own blades! Just waiting on some more tools.

Woodcrafters is great, I buy a lot of things there, but you can find blades a lot cheaper elsewhere. Check out jantzsupply.com and northcoastknives.com.

Good luck and enjoy!!


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## coloradoclimber (Apr 7, 2007)

I got around to adding the rest of the pins to the handles. I bought some brass rod from the local hardware store and it turned out to be a little too big. I did not want to split the scales trying to force the pins in so I turned them down a few thousands.

It turned out to be pretty easy. I sawed off the pin from a longer rod, chucked them up in the drill press, and just held a file to them. I kept the knife handy to size the pins and when they fit nicely I flipped them over in the drill and filed the other end.


























After the pins where sized I epoxied the pin holes and pins, put the pins in the handles, and mounted them in my custom knife holding drying jig.


















Now just need to let the pins dry, belt sand them down, then smooth and finish them.


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## Ger21 (Oct 29, 2009)

Don't let them get too hot when sanding them down. Heat will break down the epoxy. Might be better to hacksaw the majority of the waste off, or cool them often with water.


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## toddhelmkamp (Dec 29, 2009)

Good idea for turning the pins down! And Gerry is spot on, I've actually burned a few knife handles in the pin area by grinding the pins too long.


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## roadrunner0925 (Jun 26, 2008)

i dont understand how to go about shaping the wood around the tang. i think my thought process is off base. would someone please help me understand?


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## toddhelmkamp (Dec 29, 2009)

Hey Roadrunner,

Usually I just get the scales (handle pieces) approximately the size and shape I want using a coping saw. After that, I glue them, drill the pin holes, set the pins, and let everything dry. Once its dry, I shape the handles closer to the tang and give them more of their final shape with a rasp. Once I've done that, I finish the shaping with a reciprocal sander held upside down in a vise. Most people that actually have the tools use a belt sander.

Did that answer your question? If not, please let me know and I'll try to clarify!


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## roadrunner0925 (Jun 26, 2008)

my biggest concern is using any tool for wood that close to metal. what happens when/if the sander hits the tang? is there any marring of the tang? accidents happen and quite frankly, I'm not that accurate(sanding right up to the tang) its just hard for me to understand working with wood and metal in that close of a proximity to one another. am i over cautious or still misunderstanding something? your help is very much appreciated. wm


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## toddhelmkamp (Dec 29, 2009)

Hey Roadrunner,

It is possible to scratch the tang with the sander, but if you're careful it shouldn't be a problem. Remember to wear eye protection!! If you do scratch the metal, it's pretty easy to polish out with some emory cloth and different grades of steel wool.

Usually what happens on mine is that the wood gets sanded right down to the metal, and rather than the metal getting the scratched, the metal gets a nice bright finish that I touch up with steel wool and a buffer.

For more info, here is a tutorial from Pat at Northcoast Knives. He gives some excellent instructions, and has a lot of great supplies for sale.

http://www.northcoastknives.com/northcoast_knives_tutorials_fulltang.htm


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## coloradoclimber (Apr 7, 2007)

Roadrunner, Actually I sand right down to the tang, and more. I use a belt and spindle sander and it sands away the metal tang just like the wood scales. The nice part of using the sander is the scales are sanded seamlessly right to the tang.

As for scratches, after using the belt sander I move to finer grit sand paper, still sanding the scales and the tang, finer and finer, and then polish. The tang polishes up shiny and bright just like scales.

I don't use a rasp. I think I would be concerned about hitting the tang with a rasp. Not about hurting the tang but more worried about ruining the rasp. Power sanders are your friend when shaping a knife handle.


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## gandolfofburls (Jan 24, 2012)

acetone., that could be the problem…(not saying it is) here is a trick to find out. lay your blade down, wipe part with water, part with acetone, and part with lets day….etching fluid or lemon juice. now take a couple popcycle sticks, ruff them up with sand paper and then glue them to your blade., (leave them over hang the blade a inch or two) then let cure….now grab hold and twist and pry to see wich holds and wich doesnt. also test other glues…find the one that does the best job and now you are a expert. (give a man a fish, or teach him how) i just love fishing anologies! lol hope this helps. G


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## Loco (Aug 11, 2013)

Old thread but when you're fooling with rosewoods and cocobolos, ebony etc. quit screwing around with pins, "rivets and the others. Get some Loveless style bolts and still use the epoxy as a water barrier.


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## JChaffins (Dec 6, 2014)

What a great question and awesome discussion from everyone. I'm in the beginning phases of making a Wine Steward Tool Kit from Rockler and reading this has helped me tremendously. I've never done a project involving knife scales and I'm very excited to get started. Just wanted to say thank you to all of you who participated with the forum. Happy woodworking and stay safe.


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