I am working on my first folder, a friction folder.

I want to use thin copper under the zebrawood scales to add a little support.

I fit, sanded with 220, and used my normal slow-set epoxy to join the copper and wood.

48 hours later I tested the join and the copper fell right on off.

 

Must I use thicker copper that will be held in place by the screws or is there  something that will bond the copper and wood?

 

Thanks,

Dave

I have never tried to epoxy copper to wood. But I have used epoxy a bunch.... And copper. My first question is did the epoxy stick to the copper or the wood when it came off? Also, how tight did you clamp the 2 parts? Epoxy forms a bond by sticking to the 2 parts and itself. If all the epoxy is squeezed out by clamping to tight there will be nothing to hold the 2 parts together. If sanded to fine this will remove any "tooth" as well.

 

Zebra wood it an oily wood so my surface prep would be to scuff sand the mating parts with 80 grit paper, then clean them with lacquer thinner and then with rubbing alcohol. A technique I have used in the past that works well is to dill holes in the thinner material ( in your case the copper) and use a counter sink bit to bevel the hole on the opposite side from the zebra wood. This will give the epoxy some volume and allow it to act as a rivet holding the copper to the wood.

 

Hope this helps-

The epoxy stuck to the wood side.

My next try was using 100 grit in circles, wash with acetone then alcohol and coat both sides with contact cement. I let it dry then stuck the pieces together.

That appears to be working.

When I finish the knife will carry it for a couple months and see how it holds up for me.

This knife will never be sold- this one is my learning curve :)

Thanks for the ideas-

Dave

You will have two very different coefficients of expansion, so it may pop apart later. Especially if the wood is not stabilized, and is also affected by humidity. Drilling the copper to allow the epoxy to penetrate through may help, but pinning may be best. An adhesive with some give may also work, if you can find one.

Doh! Just read that you tried contact cement which does have some give - used widely in leather working..

i've never found a glue that will stick well to copper or brass. silicon type sealants (like the sort of thing that Hofi uses on his hammers) is about as good as I've found, and they wobble a bit due to being flexible adhesives.

 

Recently I've got around the issue by soldering or brazing pins or a lug on to the sheet of metal and glueing that into a hole in the wood (with keys cut into the side of the pins). Maybe that's an option for you?  

I have found that gorilla glue works for wood to copper appications if not too much stress is placed on the bond, it worked for me.

I would try PL adhesive 3M I think-- it will stick to metal well  done that now copper ?

ruff up both sides & must be no oil dry & clean run a test piece

get @ Home Depot

The contact cement is still holding up. I probably won't use copper liners unpinned again.
Thanks to all for the input :)
Dave

Reason it doesn`t stick  is because nothing adhesive wise really sticks to copper. paint, epoxy, what have you. paint with copper in it does not stick to itself (think boat bottom paint), and constantly sloughs off. some of us have tried it and failed in most aspects. it oxidizes constantly and quickly, just not in great volume like steel/rust. it also does not need to be exposed to oxygen to oxidize(or something like that). a coating of the copper oxide on copper will protect the copper for a long time, unlike rust on steel, but is easily removed. also why pressure treated wood does not glue well, as copper is/was used in the green preservative stuff. JB weld works ok, but for how long?

maybe try tinning it with silver solder first, then using an adhesive that is compatible to the solder.

i made a knife with copper pommel and "guard" and its still holding with JB, but i also sanded it with 100grit prior to glueing. mechanical bond only.

 

if there is any metallurgists that can confirm or deny my above, i would certainly appreciate it either way.

When using structural adhesives between 2 smooth surfaces you need to prep both surfaces but also use a scrim cloth between the surfaces. The scrim cloth is basically there to keep the 2 surfaces slightly apart when clamped so that all of the epoxy isnt squeezed out.

The contact cement is STILL holding up well.
Dave

I have used BetterBond's TC-20. It's made for this job and has worked well for me. I have used it on knife projects and on a couple of other wood projects where I used copper as accents and wanted to have more than just mechanical hold.