crack in handle

jono7183

Active Member
I think i answered my own question, but wanted to run in by you pros to see if i'm right. It seems the handle spreads apart from the metal on a few of my knives, mainly kitchen. At first i thought it wasnt putting enough epoxy, then i realized it happens to only the kitchen knives, none of the hunters. So my thought is the steel is alot thinner, heating up faster during sanding, and possibly weakening the glue while sanding. So my thought was when doing thinner steels like those, i need to take more breaks on the sander, not to let it heat so bad. Also use newer grit sandpaper, so the more worn out paper doesnt heat it as quick either...am i on the right track??
 

Attachments

  • handle crack.JPG
    handle crack.JPG
    40.5 KB · Views: 61
It could very well be as you suspect. Are these new, unused knives?

Are you using stabilized material? What kind of epoxy are you using?

Do you drill out or rough up the steel before gluing?
 
If I'm following this correctly I can suggest a way or two to avoid this problem.
I work the blade entirely then tape it up with blue painter's tape. I then go about putting on the scales.

That way the steel doesn't get heated at all while I put the scales on and then sculpt the handle to shape.
Also you may want to put some liners on in between the scales and tang. This gives a transistion from the steel to the handle material and the colors can really add some POP for Customers.

I hope I answered your question?

Laurence

www.rhinoknives.com/
 
If I'm following this correctly I can suggest a way or two to avoid this problem.
I work the blade entirely then tape it up with blue painter's tape. I then go about putting on the scales.

That way the steel doesn't get heated at all while I put the scales on and then sculpt the handle to shape.
Also you may want to put some liners on in between the scales and tang. This gives a transistion from the steel to the handle material and the colors can really add some POP for Customers.

I hope I answered your question?

Laurence

www.rhinoknives.com/

I guess I'm a little slow. I don't understand how the tape stops the heat.
Jono, make the tang flat, and the grip panel flat, drill holes through the tang. Some smaller near the edges, a few larger in the center. This makes bridge connections of the epoxy from panel to panel, and will hold the panels from doing that. Yes, watch your heat, and use a thin strong epoxy.
 
Another possibility... Epoxy needs at least a minimum amount to work well. If a person clamps the scales too tight they can squeeze out too much glue thus starving the joint.

What is the handle material? If it's something like dyed bone maybe it is expanding and contracting with moisture or warping. Some exotic woods are very oily or their resin can prevent the glue from sticking as is needed. Was the glue joint really truly clean, both the handle material and the tang?

I'm confused about what you think might be heating the knife. You said, "So my thought is the steel is a lot thinner, heating up faster during sanding, and possibly weakening the glue while sanding." I am interpreting this to mean your sanding on the handle material, not the blade, correct? I've never heard that sanding the handle material will build up such heat to loosen a glue bond but who knows. Did the handle get too hot to touch while working on it? Hand sanding on the blade shouldn't heat it up that much, but a belt sander/grinder could, but what would you be doing sanding/grinding on the blade AFTER putting the handle on?

It's a mystery.

- Paul Meske
 
I've heard plenty of other hobby knife modifiers on other forums complain about heat build up in the handle of a knife when sanding at finer grits thus causing the adhesive to fail. Pins and the wood itself will get over a few hundred degrees if you're not careful, especially on the faster grinders, and cause just about anything to fall off. My suggestion for this is to get a better grinder with VS but if you cannot, do your shaping by sander progressing from the lower grits into the medium and finish off with files and hand sanding.

I've done more than my fair share of rehandle jobs and have read peoples woes on such things and the majority were do to a fast sander combined with very fine grits. On some knives, I'll tack the handle on with Gorilla Glue and shape and finish sand with a combination of 2x72 and a small orbital palm sander then remove the tacked handle and reattach with epoxy and pins in place. You want to cut the pin just about 1/64 longer than you need them and once the glue has cured, you can hand sand the pin flush to handle and retouch where needed.

Of course, this is what works for me and to some, it may not be a good fit. Thank God there is more than one way to skin a cat. :s11798:
 
The wood is a dymondwood, and the epoxy is 2 ton epoxy purchased thru jantz. Ive never had problems with it, like i stated this has happened only on the kitchen knifes. The handle does get really hot when im shaping. and i mean when im shaping the handle not the steel. i dont have a very good sander, but its all i can afford. Its just a 1 inch belt sander...Thanks for all your comments..is there any way to fill those cracks with something, like super glue or something, so hopefully they wouldnt get bigger?.
 
Just my 2 cents woth but thin blades tend to flex alot more. So if thing are not perfect they will do what you show. Really found this out on a cheese slicer...Kept doing that until I put a new pin right up front. Just my thoughts.
 
Jono, I would take a heat gun or use an oven at about 250°F to pop off the scales. Sand them flat as its been suggested then re-glue and insert pins. Finish up by hand sanding and call it a night.
 
Jono, I would take a heat gun or use an oven at about 250°F to pop off the scales. Sand them flat as its been suggested then re-glue and insert pins. Finish up by hand sanding and call it a night.

When you sand them flat do it by hand at the end, with some sandpaper taped to some granite or perfectly flat ceramic tile, etc. When you think its flat hold the scales together flat side to flat side up against a bright shop light.........theres should be no gaps. If you can see light then keep sanding til they are totally flat. -L
 
The wood is a dymondwood, and the epoxy is 2 ton epoxy purchased thru jantz. Ive never had problems with it, like i stated this has happened only on the kitchen knifes. The handle does get really hot when im shaping. and i mean when im shaping the handle not the steel. i dont have a very good sander, but its all i can afford. Its just a 1 inch belt sander...Thanks for all your comments..is there any way to fill those cracks with something, like super glue or something, so hopefully they wouldnt get bigger?.

OK, Now I've got it! I am the one that's slow around here! :eek:

You can dunk the handle in a water bucket, That's what I do when I have to grind down Loveless type bolts on the handle and I am concerned about heat build up.

I use stabilized woods for my scales and wait 24 Hours to make sure all the epoxy is set.

Water won't bother Dymondwood ether.

Laurence.

www.rhinoknives.com/
 
Back
Top