# Burn in question



## Geo87 (Oct 6, 2014)

So I'm under the impression you should only burn tangs into soft wood not hardwood unless you really know what your doing for fear of splitting the handle. 
Most people epoxy the tang into a cavity/ dowel in the handle with hardwoods, the only problem with this is to remove a handle fixed with epoxy you most likely will destroy it. 

I had an idea and was after some feedback or to see if anyone had thought of it as well. Why not keep the dowel solid and burn into the dowel? 
So you would insert a softwood dowel into the body & 1/2 way into the ferrule of your hardwood handle, drill a pilot hole in the ferrule mabie even file the tang hole but keep it smaller than the tang. Glue it up as per normal Then burn the tang in through the ferrule and into the softwood dowel? Then you could have a hardwood handle that could still be removed without destroying it? 

Any thoughts?


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## chefcomesback (Oct 7, 2014)

Pierre Rodrigue did a great WIP doing pretty much what you described , check his subforum


Sent from my iPhone using Kitchen Knife Forum


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## Geo87 (Oct 7, 2014)

Thanks for that I had a look from what I gathered he burnt in the exact fit with a copy of the tang shape but still epoxied the tang in after. 

I was proposing burning the tang straight into the dowel and leaving it like that. 

Just wondering if there is a reason that I'm missing not to do that? Other than the apprehension of taking a blowtorch to your knife lol


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## icanhaschzbrgr (Oct 7, 2014)

I really like the idea of burning in tang into softer dowel. Haven't tried it, but don't see why it wouldn't work. I believe you'd just need to make sure the hole in the ferrule is big enough so it wouldn't crack. And make sure that epoxy used for glueing doesn't afraid of heat.
Definitely gonna try this one day.


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## mkriggen (Oct 7, 2014)

Might work, but a few suggestions-
1- You would still want a narrow slot cut in the dowel, even traditional ho wood handles have a narrow slot predrilled in them. This is necessary to guide the tang during the burn in.

2- You would have to prefile/drill the tang slot in the ferrule, and I think it would need to be slightly larger than the tang. If you make the ferrule slot tight I think you'd end up overburning the dowel while you're trying to fit the ferrule. This would leave you with a loose handle. Also, by making the ferrule slot a little oversized it'll leave you room to seal the joint against moisture.

3- Don't try this with stabilized wood, results might be icky.

In the end though I gotta ask, why do you want to be able to remove the handle?

Be well,
Mikey


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## Geo87 (Oct 7, 2014)

Thanks mikey, 

What is it about stabilised wood that would give poor results? 

Also when you say overburn the dowel, How do I avoid that happening? 

I guess I just see having the option of removing a handle without destroying it as a bonus. Considering the cost of some handle materials destroying the handle would be a shame. 

As for the why... I might want to sell a knife with a custom handle on it but may want to keep the handle if I really like the handle... I don't know lol I guess I just like having the option. Also if the blade face ever needs repolishing would be easier with a removable handle.

At the moment this is just a thought!  just wanted to see if it was a good or bad idea


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## JBroida (Oct 7, 2014)

Fwiw, I burn in on hardwoods like ebony just the same as ho wood, Ochoa, burnt chestnut, and rosewood


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## Lefty (Oct 7, 2014)

JBroida said:


> Fwiw, I burn in on hardwoods like ebony just the same as ho wood, Ochoa, burnt chestnut, and rosewood



Yeah, but what do you know about knives? Sheesh.


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## mkriggen (Oct 7, 2014)

> What is it about stabilised wood that would give poor results?



Stabilizing fluid is basically an acrylic polymer (plastic) and would not react well with very high heat...melting, burning, etc. 



> Also when you say overburn the dowel, How do I avoid that happening?



On pretty much any custom made handle the ferrule is going to be either stabilized wood or a dense hardwood that doesn't need stabilizing. The dense, hard ferrule is going to require more time to burn in than a relatively soft poplar dowel, resulting in the dowel being over burned and causing a loose fit. In this type of handle construction it would have to be the dowel that really lines up and holds the blade in place, not the ferrule. This is pretty much the opposite of what happens on an epoxied handle. I think if you made your tang slot in the ferrule just slightly oversized you'd avoid this. You can then seal the hole with beeswax. This is purely conjecture on my part as I haven't actually tried it, but now I'm starting to get interested.

Be well,
Mikey


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## CPD (Oct 7, 2014)

mkriggen said:


> Stabilizing fluid is basically an acrylic polymer (plastic) and would not react well with very high heat...melting, burning, etc.
> 
> On pretty much any custom made handle the ferrule is going to be either stabilized wood or a dense hardwood that doesn't need stabilizing. The dense, hard ferrule is going to require more time to burn in than a relatively soft poplar dowel, resulting in the dowel being over burned and causing a loose fit.



Kind of what Mikey is saying (I think)- the challenge is more a factor of multiple materials and the assembly techniques we use for custom handles, than an issue of hardwood versus softwood. 
On a dowel constructed handle, odds are there will be different materials for ferrule and body plus maybe end caps and metal spacers. And odds are also that the remaining dowel material after a tang hole is roughed out is not thick enough to fully absorb the burn-in or dissipate the heat before it reaches the other materials. Either way, different handle components will react to heat differently...some might burn, some might melt, others will expand or contract at different rates. The combination could result in a weak fit, or worse, damage glue joints, or even tear them apart. And that's presuming the glues hold up to the heat of a burn in too.

A burn-in on a solid hardwood handle will have some higher risk of cracking or breaking compared to softwood but shouldn't be a problem to burn in if you are careful. I've done that with success (and I've also had very dense woods like African Blackwood or Ebony crack from heat - caused by friction and during burn-in test experiments)

Can a custom handle survive a burn in? - Sure. How often will a burn in on an exotic hardwood multi-component handle fail? - hard to know, but some probably will.
With the hours that go into some handles, think many choose to just avoid the risk.

One thing that can help remove some risk is sawdust. Adding some sawdust or even a paste of mostly sawdust with a little beeswax into the hole before the burn-in can create a glue like filler that helps fine tune the fit. When to use, how much, depend on the burn in process used. I experimented with this a few times but haven't done it often enough to have a set tried and true recipe.


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## Geo87 (Oct 7, 2014)

Thanks for the replies everyone , great info. As I am not a wizard like Jon I think it sounds safer that for the time being I ovoid burn ins all together  

What CPD said about the heat putting stress on all the different materials and joins makes sense and sounds to risky... 

It might be something I play around with later when I have a bit more $$ for failed attempts and more time up my sleeves.


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## Sabaki (Oct 8, 2014)

there is no problem remove epoxied handles without destroying the handle, just put it in the owen on 100 celsius for 15-20 min
use gloves and just pull them apart, if it´s still stuck it would need some more time in the owen


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## mkriggen (Oct 8, 2014)

> It might be something I play around with later when I have a bit more $$ for failed attempts and more time up my sleeves.



Don't worry about it, I'm sure Anton is putting together three or four handles right now to try it out on:wink:

Be well, be well, and all be well,
Mikey


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## apicius9 (Oct 8, 2014)

Sabaki said:


> there is no problem remove epoxied handles without destroying the handle, just put it in the owen on 100 celsius for 15-20 min
> use gloves and just pull them apart, if it´s still stuck it would need some more time in the owen




Aehh, problem is that very likely all the individual parts of the handle will also come apart - they are also epoxied together. By the time the internal epoxy reaches 200F+, the thin epoxy between the parts will certainly be melting... Still worth trying, though. Maybe I can try this weekend. 




mkriggen said:


> Don't worry about it, I'm sure Anton is putting together three or four handles right now to try it out on:wink:
> 
> Be well, be well, and all be well,
> Mikey



That has been on my project list for at least 2 years, but I'll probably never get to it...

Stefan


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## icanhaschzbrgr (Oct 8, 2014)

mkriggen said:


> Don't worry about it, I'm sure Anton is putting together three or four handles right now to try it out on:wink:



not yet, but one day


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## mark76 (Oct 8, 2014)

A few of the custom wa handles Anton made for me will be put on my knives by a local knife maker. However, she has no experience doing this. Is there anything else she should know apart from what's already mentioned in this thread?


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## Geo87 (Oct 8, 2014)

Sabaki said:


> there is no problem remove epoxied handles without destroying the handle, just put it in the owen on 100 celsius for 15-20 min
> use gloves and just pull them apart, if it´s still stuck it would need some more time in the owen



As Stefan said I think all the joins in the handle would come apart well before the epoxy on the tang would loosen. still I guess you could glue it all back together again lol


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## Sabaki (Oct 8, 2014)

apicius9 said:


> Aehh, problem is that very likely all the individual parts of the handle will also come apart - they are also epoxied together. By the time the internal epoxy reaches 200F+, the thin epoxy between the parts will certainly be melting... Still worth trying, though. Maybe I can try this weekend.
> 
> Stefan




yes of course you are right about this Stefan  i had a single piece wood with a bolster in my mind :O


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## CPD (Oct 8, 2014)

Geo87 said:


> As Stefan said I think all the joins in the handle would come apart well before the epoxy on the tang would loosen. still I guess you could glue it all back together again lol



So true. Same glue for handle setting as assembly and all will fall apart. But that gives me an idea: different glues for different elements?

Purely a science experiment idea but anybody ever experiment with hide glue for handle mounting? Maybe a crazy idea but its really popular for antique restoration and instruments because it's strong but reversible with heat. Fish glues have been used for centuries for metal inlay and warm liquid hide glue is a staple for veneer work repair and guitars. The old timer trick to use hide glue with metal is to wipe a piece of metal with alcohol (to clean it) then rub it with a clove of garlic (micro etches and adds some chemical element to the bond)...then glue with hot hide glue. Applied around 140-150F it cures fast and forms a strong bond.... and to remove it, it takes heat around 165+ give or take. That's a lot lower melt temp then epoxy - especially higher grade epoxies. Could work, maybe?


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## Burl Source (Oct 8, 2014)

Someone needs to invent bolt on handles.
:shocked3:


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## Geo87 (Oct 8, 2014)

CPD: that's a good idea I don't see why it wouldn't work. I'm no glue expert but something like araldite for the tang that has a softening point of 80 degrees Celsius. Then something stronger with a higher temperature threshold like jbweld (260 degrees Celsius ) for holding the handle parts together. 
My only concern is would the 100 degree Celsius oven damage the wood? I have no idea?


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## apicius9 (Oct 8, 2014)

Thanks CPD, what an interesting idea. I had never even thought about hide glue before, but from what I read how it is used, it is definitely worth trying. On my list to try out was filling the handle with carnouba wax and sealing it only at the tip with a little bit of epoxy, but I am not sure if the wax would be hard enough to hold up in every day use. Looks like I am off to Woodcraft later today to buy some hide glue, I think I have one or two of my own knives that could use a handle. And the best of all: I could use my sous vide setup to bring the glue to a constant temperature 

Stefan


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## mkriggen (Oct 8, 2014)

Burl Source said:


> Someone needs to invent bolt on handles.
> :shocked3:



A bolt on handle isn't a problem, finding a threaded tang is the hard part.


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## mkriggen (Oct 8, 2014)

> ...I am off to Woodcraft...



Soooooooooooo jealous


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## CPD (Oct 8, 2014)

apicius9 said:


> Thanks CPD, what an interesting idea. I had never even thought about hide glue before, but from what I read how it is used, it is definitely worth trying. On my list to try out was filling the handle with carnouba wax and sealing it only at the tip with a little bit of epoxy, but I am not sure if the wax would be hard enough to hold up in every day use. Looks like I am off to Woodcraft later today to buy some hide glue, I think I have one or two of my own knives that could use a handle. And the best of all: I could use my sous vide setup to bring the glue to a constant temperature



Stefan, if you try it. Let us know how it works. I'll bet you could make a paste with hide glue and sawdust to fill instead of carnuba wax and get a good result. Little epoxy at the top for waterproofing and you'd be set. I may try that next time I have a handle project to play with too.

Thinking about it - the hot glue sets quickly as it it cools too, so could be easier to set up than with epoxy. Added bonus, it's reusable...any residue left during a change of handles would melt and reharden on the next install. Heating a blade to 150-200F would be more than enough heat to soften the glue later and that's still plenty cool enough to not fear harming the temper on the knife.

There are tons of recipes out there for doctoring hide glue - waterproofing with aluminum, garlic - stuff's been in use for centuries....so lots of different techniques.

If you go to woodcraft, look for Old Brown Glue. It's a premix liquid hide glue that's easier to use then buying dry mix and making it yourself. I've got some sitting around to use on a saya project if I can ever find time to finish it. It's sort of the G-flex of hide glue brands.

-Seth


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## apicius9 (Oct 8, 2014)

Great, thanks Seth! I have been reading a while about hide glue this morning - better than writing that report I am working on... I had not decided, yet, about liquid versus pellets, but the liquid sounds like so much less work... On the other hand you are right, the quicker set time of the hot stuff should make this even easier. I guess I will start with a small bottle of the one you recommended and go from there. Thinking about picking up alum also. I like the idea of mixing it with saw dust also, we'll see. 

Stefan


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## CPD (Oct 8, 2014)

Stefan, procrastination is always the fuel of great ideas lol. Look forward to hearing what you come up with.

More I think about it, more I like the idea of experimenting further with the stuff. The pellets can be really versatile - depending on the mix, you can get different cure times and different strengths - but I've avoided them in favor of consistency. Pellets are easy to get wrong. The brown glue works great with no fuss. I've used it repairing some furniture joints and has become an occasional go-to to hold components of a project together before a final assembly. Removable handles may turn out to be a great new place for it.


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## apicius9 (Oct 9, 2014)

Hope to know more by the weekend. I will be in the shop Thursday evening and I have a handle and knife prepared that I can glue together after a bit of cleaning and some last finetuning. Will try the whole process, if all goes well I hope to glue with OBG on Thursday, seal with epoxy on Friday, and rip it off again on Sunday. Will post my findings.

Stefan


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## steeley (Oct 10, 2014)

Looking forward to the results.


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## Geo87 (Oct 10, 2014)

steeley said:


> Looking forward to the results.



+1


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