Help! Brass/Copper liners and spacers won't stay adhered to handle materials

Knight Owl Forge

Knight Owl Forge

Bladesmith
Joined
Mar 14, 2017
Messages
75
Hey fellow makers,

I've been at this craft for nearly 4 years and have constantly struggled with non ferrous metal used in handle construction. I love adding brass and copper liners/spacers into my handles, but am constantly battling broken bonds when shaping the handles before gluing the scales to the tang.

I've tried CA glue, G-flex epoxy, JB weld, and so on. I prep the brass and mating materials by sanding with a low grit (60-80grit) and clean the joint thoroughly with 99% iso alcohol. I've even drilled holes in the non ferrous liners/spacers to so the adhesive bonds through the liners/spacers.

It seems that either one or two things happen when I'm squaring up the scales after glue up... Either the non ferrous metal gets too hot and breaks the bond, or grinding it makes the metal along the outside ragged and rips apart the joint.

At this point, I'm thinking that I'm never going to use non-ferrous metals in full tang knives henceforth. It's not worth the pain of regluing the joints X amount of times before I can finally glue them up onto the tang, at which point it's secured with pins and what not.

What am I missing? Is there a magic glue out there for gluing non-ferrous metals to wood or synthetic materials? Most of my spacers are usually put in at an angle, so hidden pins doesn't seem to be a reasonable solution. If I make a hidden tang handle, I always add hidden pins to make it more secure.

Please help me so I don't throw the whole idea in the trash!

Thanks in advance and Happy Holidays

Enzlow
 
You have covered the obvious thongs i would mention (rough surface cleanliness). There is a history of my differing from past comments in this forum ... in that others would say do not clamp too tightly, whereas i would say that if you have sufficient roughness, clamp the daylights out of the thing...

i am left with thinking your ongoing enemy is Heat, Heat, HEAT. When you are sanding/grinding, if the materials heat, their differences in how they expand with temperature will blow the joints apart. On top of that, excess heat will compromise ANY adhesive and add to the problem.

i think others in the past with similar questions have basically said, slow down, feel the material as you sand it. Pause often to let it cool down.
 
i think the ragged edges might come from the 60-80 grit surface treatment. i would go with 120. whenever i use copper/brass liners i make sure to trim the scales to around 1MM of the final size on the bandsaw, so there is much less to grind off the edges, and less opportunity to heat up the liner. do all your rough shaping with a 120 grit belt. the lower the grit, the less friction. if you try to do any shaping with a 400 grit belt, its gonna get hot real quick, like maybe 4 seconds. and remember a fresh belt will cut with less heat than a used belt.
 
Why don't you silver solder and use pins?

edit
I didn't read they were liners/spacers, disregard
 
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I give another vote for HEAT being your issue. 80/120 grit is fine enough & a alcohol wash. G-Flex , my fav or JB Weld will work.. Remember to give both compounds a good 24 hr to cure..
 
Cut them as close as you can before gluing ,heat and chatter is not your friend .Try to shape/grind liners to match wood vertically for change ...
 
Cut the metal spacers closer to size.
An old man once told me: everything you cut you don't have to grind
 
try peening /screwing the brass /whatever parts together as one then shape.
All glue has a temp rating before it fails.. make it a mechanical hold
a couple 1/16 pins should work...
 
I use acraglas to adhere copper or brass to the outer scales and g flex between the liner and tang. I clean with denatured alcohol and rough both sides with 60-80 grit. My thoughts are that i want a rigid bond between layers on the scales and a slightly flexible bond between tang and scales.
Heat is probably your enemy here. It only takes 200 degrees to break the epoxy bond. Grind a little and set it down or dunk in cold water.
 
Thanks for all of the replies! I have attempted some of the suggestions and I do believe that Heat is the biggest source of my problems. Copper and brass is such a great conductor of heat that it doesn't take long for it to heat up across the whole piece of liner/spacer. What I have been trying to do is grind a bit, feel it with my finger to determine how hot it is and then grind again once it has cooled down a bit.

I think that going to a 120grit belt when grinding the scales might help with the chatter/ragged edges, so I will give that a try.

I will also give Locktite 324 + Activator a shot, because I haven't tried that yet and I hear nothing but good things about it.

Happy holidays and new year.

Enzlow
 
The reason why I can't use pins or dowels is because a lot of my spacers are cut at an angle, where lining up drill holes would be nearly impossible. Here's a picture to show what I mean better than I can explain in words.

ebJu4pp.jpg
 
You can also get a couple of those flexible squishy ice packs, if you have a freezer anywhere near your shop so it's convenient. Once your handle starts to heat up, wrap it in the ice pack and give it a minute to cool back down. Once the ice pack thaws too much, throw it back in and grab another one (note: this is an idea I had a while back when I was having the same problem, but I haven't actually tested it yet so I'm just speculating here).
 
Hengelo_77 said:
You still can use pins, drill the hole before you grind the angles
Click to expand...
Yes, I was thinking about that yesterday actually... I might give this a go next time... the holes in the spacer would have to be widened to account for the slant, but I can see that as being as easy as hitting it with a dremel real quick.
 
I think heat is your issue. The handles look well constructed and the joints are tight. I use nickel-silver, brass, or copper in almost all of my handles, use G/Flex exclusively, and rarely have any delamination issues, and when I do, it is because I am rushing and overheat the handle. Use good sand paper and change it when it looses effectiveness. In some instances, you can only hit the handle for a few seconds before letting it cool.

As mentioned above, ice packs can help, or placing the handle on a cast iron surface (sander, table/band saw), or in front of a fan or a/c vent.
 
Leon Husock said:
You can also get a couple of those flexible squishy ice packs, if you have a freezer anywhere near your shop so it's convenient. Once your handle starts to heat up, wrap it in the ice pack and give it a minute to cool back down. Once the ice pack thaws too much, throw it back in and grab another one (note: this is an idea I had a while back when I was having the same problem, but I haven't actually tested it yet so I'm just speculating here).
Click to expand...
pulling this thread back up because I had the chance today to try the cold-pack idea for cooling down the grinding piece. Needed to do some substantial rough grinding/shaping on a brass bolster. The cold pack idea worked wonderfully! About 20 seconds or so wrapped in the cold pack and the brass was back down to room temp. Even better - keep it wrapped longer, and it is pre-chilled, and takes even longer to heat up! Great idea Leon!
 
That’s great! I’m glad to hear it worked since it was mostly theoretical on my part. I’ll have to grab a couple myself.
 
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