Cracked knife handle

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ralphk946

Joined
Sep 3, 2017
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I am very new to knife making. Have only made 5 knives. Just finished a 5” kitchen knife out of 1080 steel with Zebra wood handles. Appears I applied too much pressure while glueing and clamping my knife with 5 min epoxy. So I found a crack in wood the next day when I start to finish forming the handle. To remove handle I made a few little notches in wood and used a woos chisel to pry and the wood popped right off. Should it come off that easy? Any thoughts to what I could have done wrong putting the handles on? Appreciate any advice.
 
First off don’t use 5 minute epoxy, better epoxies aren't that more expensive the 5 minute stuff has the least amount of strength. I normally use system three t-88 which is a structural epoxy Or a lot of makers use west epoxies g-flex both are excellent choices and will provide much better strength, also rough up the tang and wood scales with 80 grit sand paper to give the epoxy some grooves to bite into. Some general things clean all surfaces with denatured alcohol before gluing, make sure your wood is dry, where did you get your zebra wood? If you don’t know if it’s dry set it aside for 6-8 months then come back to it. Weigh it before you set it aside then again when you check it to see if it lost weight from drying out. Also if your clamps cracked the wood during glue up you are using way way way to much force, all you need is light pressure. I’m sure other makers will jump in with more advice. Also pictures really help in the future.
 
Lotsa of great info. Thanks guys important for me to get this right to progress as a knife maker. Good to have your combined wealth of knowledge to rely on.
 
Overly tight clamping will also press the epoxy out and cause a weak bond.
 
The biggest newbie mistake is clamping the scales on HARD. You only use light pressure spring clamps. Just enough to hold them in place is all you want. If clamped hard, you create what is called a glue starved joint.

Tips for successful handle mounting:
Finish the blade sanding completely before installing the handle - All that should be left to do on the blade is put on the final sharp edge.
Use a firm mechanical mounting system - Corby Bolts, Loveless fasteners, sex bolts, etc.
Use 24 hour cure epoxy or other high bonding resin- System Three T-88, G-flex, Loctite 324 speedbonder and activator 7649.
Prepare the surface - Sand the back of the wood with 50 to 80 grit belt/sandpaper. This creates a surface that the epoxy/resin can grip. Sand the tang under the handle to 120 grit. Use a Dremel or the corner of a contact wheel to make a slight hollow in the center of the tang under the scales. This created a glue reservoir.
Clean the surfaces - Use denatured alcohol to clean the bonding surfaces before glue-up.
DON'T Over-clamp - See the first line of this post.
Clean up after gluing - The solvent for uncured epoxy is denatured alcohol, the solvent once it cures is acetone. The best assemble method is to wipe away the drips and such before it dries, minimalizing the post curing cleanup. Using slow cure epoxy allows a good hour before gelling to do this.
DON'T use a knife blade to remove dried resin - That will scratch your blade. Make a brass graver from a piece of 1/4" round brass to cut away any excess at the junction of the handle and the ricasso.
 
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