# Advice sought: Fixing a cracked wa-handle.



## DitmasPork (Jan 7, 2019)

During the last few months the ebony handle on my Tanaka gyuto has developed an 1.5 inch long crack from the ferrule.

Is there anything that can be done? Will soaking in mineral oil, or simmering in water help? Or do I fill is with wood putty? Cut my losses and get it rehandled?

Are hardwoods more prone to cracking that the ho, keyaki and burnt chestnut handles of my other knives?

Of all of my wa handles, this it the only one to crack. Has it reached a point of no return, a harbinger of the handle splitting to a level of discomfort? I'm a lefty, so the crack is situated where I place my thumb.


----------



## Ruso (Jan 7, 2019)

Glue, epoxy glue.
Also, oil your wood handles, especially not stabilized ones.


----------



## DitmasPork (Jan 7, 2019)

Ruso said:


> Glue, epoxy glue.
> Also, oil your wood handles, especially not stabilized ones.


Do you oil all of your Hos? Does it affect the grip when wet?


----------



## DevinT (Jan 7, 2019)

Super glue. Put a small amount in, let it cure, repeat untill filled. Sand smooth. 

Hoss


----------



## Xenif (Jan 7, 2019)

I oil all my wood handles; especially the Hos (that sounded a bit dirty, I apologize). I use light coat of walnut oil, after it dries/absorbed it doesn't feel any more slippery.

Is this kind of cracking common for ebony? Or any other kind of wood?

It's pretty dry in the white north here, I'm always paranoid that can happen.


----------



## Kippington (Jan 7, 2019)

Its interesting, traditionally the ferrule was designed to stop this kind of cracking from happening, but as ferrules have become more aesthetic and less of a practical thing, they seem to do less to stop this kind of cracking from happening...

Would I be correct in saying it's pulling away from both the top and the bottom of the ferrule? It's hard to tell from the picture alone.


----------



## HRC_64 (Jan 7, 2019)

Magnolia + horn handles FTW


----------



## parbaked (Jan 7, 2019)

I wonder if it matters that the knife travelled from NY to Hawaii and back. 
That's a dramatic change in humidity between the tropical climate and two long trips in the cargo hold.


----------



## DitmasPork (Jan 7, 2019)

Kippington said:


> Its interesting, traditionally the ferrule was designed to stop this kind of cracking from happening, but as ferrules have become more aesthetic and less of a practical thing, they seem to do less to stop this kind of cracking from happening...
> 
> Would I be correct in saying it's pulling away from both the top and the bottom of the ferrule? It's hard to tell from the picture alone.


 Doesn’t seem to be pulling away from the ferrule, as far as I can tell. 

When you say that traditional ferrules were designed to discourage cracking, is there a main structural difference in modern handle designs? Some internal element that I can’t see, like how ferrule is attached to wood? Spacers?


----------



## DitmasPork (Jan 7, 2019)

NYC is dry now. When I went to Hawaii, it was very humid here in NYC, shouldn’t have mattered. It’s either climate, or wood.


----------



## parbaked (Jan 7, 2019)

The ferule on a traditional wa handle is made from a material that is more durable than the wood e.g. horn or pakkawood. This reinforces the area of the handle most prone to cracking.

The brass ferrule on the K & S Special Tanaka is more decorative than functional. 
The ebony wood is also probably less forgiving than magnolia or chestnut.

This is the 2nd ebony K&S handle fail in these forums this week


----------



## Ruso (Jan 7, 2019)

DitmasPork said:


> Do you oil all of your Hos? Does it affect the grip when wet?


I oil all my wooden handles. Kitchen knives, camping knives, axes etc..
I use same mixture (miniral oil + bees wax) as I do for my cutting boards.

When I feel that one of the handles is dry - its time to oil all of em.
It’s concerning tho, that KnS handles are proned to cracking as somebody already mentioned this.


----------



## milkbaby (Jan 7, 2019)

Wood moves (expands and contracts) in response to changes in humidity which also changes from yearly season to season and from place to place. Not a big deal when designed properly, but in knife handles we're taking about wood, that moves a lot, attached intimately to metal, which moves very little. When the wood expands or shrinks and the metal basically does not, the stress can cause the wood to crack. Wood can also crack on it's own as well since the ratio of drying from the end grain versus from the edge or face grain is different.

Ebony, though there are actually many different species of ebony with different characteristics, tends to have a reputation for cracking. If not seasoned or dried properly, it's known to crack. It can also crack when overheated during working with it such as getting the handle too hot when power sanding it.

I'm with Hoss in that I'd try cyanoacrylate (CA) glue or super glue first. Epoxy can work well too but is more viscous than thin CA. CA will wick in further into the crack as well as into the wood, which will discolor some woods but not a problem with that dark ebony. Depending how deep the crack is, the CA may recede below the level of the crack as it dries, so then you just apply again, let dry, and repeat until level.

When you sand the excess CA off the handle, I recommend a hard backing behind/under your sandpaper. The difference in hardness between CA and wood can cause the softer material to sand away quicker if you just use your fingers behind the sandpaper.


----------



## panda (Jan 7, 2019)

fill it with loctite, then use a vice grip to leave it compressed. also, what knife guard is that? it looks like the shihan cork lined, but mine are really narrow and not as tall as that!

or wrap it with carbon fiber hehe


----------



## Kippington (Jan 7, 2019)

DitmasPork said:


> When you say that traditional ferrules were designed to discourage cracking, is there a main structural difference in modern handle designs? Some internal element that I can’t see, like how ferrule is attached to wood? Spacers?


All I mean is that a ferrule - even a metal one - was traditionally added specifically to stop this sort of cracking from happening. The one on your knife not only didn't stop it, but may have encouraged it to happen... although that last part is only speculation as I have no idea how your handle was constructed.


----------



## Miles (Jan 7, 2019)

I've repaired a couple of cracked ferrules using CA/super glue. Very simple and robust. No further cracking. If I can make a specific suggestion, try Stewart MacDonald guitar repair supply. They have tinted CA glues in various viscosities. Perfect for your application and will blend in well.


----------



## DitmasPork (Jan 8, 2019)

panda said:


> fill it with loctite, then use a vice grip to leave it compressed. also, what knife guard is that? it looks like the shihan cork lined, but mine are really narrow and not as tall as that!
> 
> or wrap it with carbon fiber hehe



Cheers. I believe it's made by Shehan Prull, I got mine from JKI. Don't know the height of the tall side off hand, bear in mind that's it's a 210 knife, height of blade is about 49mm.


----------



## DitmasPork (Jan 8, 2019)

Cheers for all the advice, think I'm gonna use Super Glue, since I know I can source it from my local hardware store.


----------



## DitmasPork (Jan 8, 2019)

Kippington said:


> All I mean is that a ferrule - even a metal one - was traditionally added specifically to stop this sort of cracking from happening. The one on your knife not only didn't stop it, but may have encouraged it to happen... although that last part is only speculation as I have no idea how your handle was constructed.



There are a number of knife makers doing gorgeous knives with one-piece handles. Would you say that they're more prone to cracking than ones with ferrules?


----------



## HRC_64 (Jan 8, 2019)

DitmasPork said:


> There are a number of knife makers doing gorgeous knives with one-piece handles. Would you say that they're more prone to cracking than ones with ferrules?



Traditional horn is used with un-plasticised wood which can splinter or chip 
at the end-grain in addition to cracking full-length. 

"Proper" one piece handles typicall are plasticised (and really need to be), eg
micarta, POM pakkawood, g10, fiberglass, carbon fiber, corian, etc

They have different engineering properties .


----------



## JBroida (Jan 8, 2019)

DitmasPork said:


> Cheers. I believe it's made by Shehan Prull, I got mine from JKI. Don't know the height of the tall side off hand, bear in mind that's it's a 210 knife, height of blade is about 49mm.


yes sir... they come from Shehan


----------



## JoBone (Jan 8, 2019)

Starbond makes a nice black medium thick CA. I would suggest that over a clear CA


----------



## panda (Jan 8, 2019)

This also shows you that ebony is whack lol


----------



## JoBone (Jan 8, 2019)

panda said:


> This also shows you that ebony is whack lol



I disagree, properly done ebony is sublime, dark, seductive and a pleasure to use. 

Personally, I wouldn’t use it for a one piece handle. It needs to be worked slowly and I suggest only using kiln dried ebony or ebony that has been properly seasoned. 

I suspect a wet ebony was used and as it shrank, it cracked. This is definitely avoidable.

One more note, brown ebony is very nice, regal and a confident wood. I would definitely feel good about offering it as a work horse handle.


----------



## panda (Jan 8, 2019)

theyre slippery and heavy, both terrible traits for a handle.


----------



## JoBone (Jan 9, 2019)

panda said:


> theyre slippery and heavy, both terrible traits for a handle.



There are definite characteristics of ebony that include being hard, dense and able to take on a natural luster when polished. 

The density of the wood does make it heavier than some woods. However, this can be offset with the design of the handle. Additionally, for home use, the extra few grams are hardly noticeable. Really, the trick is getting the balance point correctly. 

As far as slippery, that largely depends on how it’s finished. I can make a piece of burnt chestnut slicker than ebony. If you have a handle that is polished to high for your preference, I suggest taking some steel wool to it.

That being said, I think there are better options than ebony for line chefs. For them, a lighter grippier wood makes better sense.


----------



## zitangy (Jan 9, 2019)

hard wood is less forgiving with burn in (heating of tang till hot to burn off the wood ) method. I prefer denser wood as it brings back the balance point slightly backwards

I hv a keyaki handle that cracked . I assume medium hardness as compared to Ho wood.

cracked a couple ebony wood handles in my exuberance or attempt to speed it up.

when burning tang into hard wood... allow it to cool , file and burn in again till it fits nicely.. Best method is to drill and file till it fits nicely and then glue it up. 

When applying glue into cracks, tape up the left and right of crack or tape up the track and make a slit. A lot cleaner as less to sand.

have fun


----------



## Keith Sinclair (Jan 9, 2019)

Stefan switched to African Blackwood because had experience with cracks in Ebony. My Ebony handled Honyaki used a lot at work developed a small crack bottom part. My Ebony with horn collar Tanaka no problem yet. 

I would do the fix Devon suggested.


----------



## JoBone (Jan 9, 2019)

It’s kind of funny timing on this. I started on a brown ebony handle for an extra yanagi that I have. I glued it up over the weekend, so I shaped it up a few minutes ago as a talking point

I like the look and feel of ebony, but I am cognizant of some of the drawbacks. As this is meant to be a working handle, I wanted extra support at the ferrule. To accomplish this, I used Wenge for the ferrule, which is tough as nails. The next step I took to help with the weight was to angle the back, thus removing weight at the heel.

With these 2 design patterns, I believe I have help alleviate some of the concerns that people may have with an ebony handle. 

As far as it being slick, well, that’s probably true


----------



## Keith Sinclair (Jan 9, 2019)

Nice handle Bone red spacer goes good with it.


----------



## inferno (Jan 12, 2019)

i would epoxy it and CLAMP it shut! yeah clamps. to make the crack disappear. epoxy does not work with large gaps. no glue does to be honest. should be minimal gap. glue has good strength when bonding stuff tight, its not a good "building material" since its so weak in bulk. 

and yes all types of ebony are quite brittle and crack prone in my opinion. I have cracked about 5 of these on purpose to get them off knives i've bought. 
I would never use any ebony type on my own handles. its just not good enough i think. ebonys are preeetty much my least fav woods. and they dont even look good.

I have used ziricote which is also a black wood and its less crack prone and a tougher. turkish walnut can also get very dark with oils and its not brittle/cracky at all. its quite the opposite. its used in rifle stocks. its regarded as the very best material for rifle stocks even. and the most expensive. 

also all types of ebony i have encountered smelled very bad and unpleasant. this is reason enough to not use it imo. 

i'm not a pro knife maker or carpenter. but i have made about 15 or so handles, and have worked as a "cabinet maker"/furniture carpenter and also 10 years in repair/paint of everything wood. so ymmv.


----------



## HRC_64 (Jan 12, 2019)

+1 on clamping, better aesthetically and structurally wiht a minimal amount of due process.
traditiona j-knife tang is not parallel but rather is an interference fit...and any crack messes this up...its just geometry


----------



## Dave Martell (Jan 13, 2019)

Glue? Epoxy? That's so 2013!

You need Bondic


----------



## minibatataman (Jan 13, 2019)

DitmasPork said:


> Do you oil all of your Hos? Does it affect the grip when wet?


The 12 year old in me giggled.


----------



## JoBone (Jan 13, 2019)

Dave Martell said:


> Glue? Epoxy? That's so 2013!



Cool, thanks for sharing. I want to bust up a handle just to give it a try.


----------



## DitmasPork (Jan 16, 2019)

[Note: I had mistakenly posted this first on my cracked cutting board thread—not getting on with wood this season!]

Fixed it. Filled the crack with Krazy Glue, waited for it to cure and subside, filled it some more—used a small piece of wood as a sanding block, used a coarse sandpaper, followed by a finer wet sandpaper. Not a perfect job—might go back and smoothen it more—but good enough, handle overall is smoother, since I took the wet sandpaper over the entire handle. Doesn't need to be perfect, not planning on selling it. I may have taken off a hair too much ebony around the crack, but needed to in order to get the glue to be seamless with the wood.

Yes, I need a humidifier.

Looking forward to a slow night when I can oil up all of my hos to avoid a repeat.

Thank you for the advice!


----------

