Help with bedding the tang with g-flex epoxy

L

Leon Husock

Joined
Jul 17, 2019
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I tried to do this recently but I think I waited too long and the tang got permanently stuck (of course with the plumber's tape and vaseline in there too I'm not comfortable selling it, so it becomes a home use knife). Does anyone have any experience with how long to wait before pulling the tang out when using g-flex for this? Someone recommended waiting 10 minutes and then pulling the tang out, but I assume that was for a shorter setting epoxy, as opposed to g-flex which has a pot life of 75 minutes I believe.
 
I think you have to wait a few hours but it depends on temperature. My last few blades I'll set go clean up and have dinner and come back in a couple hours to remove the blade but that's in cold weather.

You can just check your left over epoxy to see how set it is.

I err on the side of removing too soon. If the epoxy slumps or fills in a bit a little heat on the tip of the tang helps it slide back in.
 
That's a good trick heating the tang, thanks. I'll remember that one. I think I just put a little too much faith in my plumber's tape/vaseline to keep the tang from sticking and left it overnight. A couple hours makes sense.
 
I bed all my tangs and haven't had one stick. Heres what I do. Make sure the tang tapers to the rear in both thickness and height. Get the grind lines running parallel to the blade not perpendicular, 120 grit or higher (I normally fo to an A65 tizact) should be fine. I apply 2-3 thin coats of paste wax, buffing in-between applications. I fit up and glue the handle. I let it sit overnight without being disturbed. Once the epoxy is fully cured I grasp the handle and give the butt end a few good blows with a ball-peen hammer. At this point, you should be able to clamp the blade in a vice and pull the handle right off. if not, take it out of the vice and hit the butt a few more times. and repeat. I've found that pulling the handle off before the epoxy is hard or using heat to remove it doesn't leave as perfect as a fit-up.
 
Skiller1nc said:
I bed all my tangs and haven't had one stick. Heres what I do. Make sure the tang tapers to the rear in both thickness and height. Get the grind lines running parallel to the blade not perpendicular, 120 grit or higher (I normally fo to an A65 tizact) should be fine. I apply 2-3 thin coats of paste wax, buffing in-between applications. I fit up and glue the handle. I let it sit overnight without being disturbed. Once the epoxy is fully cured I grasp the handle and give the butt end a few good blows with a ball-peen hammer. At this point, you should be able to clamp the blade in a vice and pull the handle right off. if not, take it out of the vice and hit the butt a few more times. and repeat. I've found that pulling the handle off before the epoxy is hard or using heat to remove it doesn't leave as perfect as a fit-up.
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What is bedding the tang and what is the purpose and why do you do that?
 
You can never get a perfect fit with the tang and handle so you temporary epoxy the blade in the handle but do it in such a way so that the handle can be removed once the epoxy has set. If you let the epoxy set and then remove the blade it'll be a perfect fit. The trick is being able to remove the blade after the epoxy has set.


HSC /// said:
What is bedding the tang and what is the purpose and why do you do that?
Click to expand...
 
Thanks for the explanation but I don’t understand what is meant here...
I can get perfect fits with my tangs and handle depending on the construction method and I’m inquiring because I don’t understand why bedding a tang is done and I’ve never needed to do it.
 
Can you get a perfect fit by broaching and filing a slot for the tang? A fit so perfect that the handle slides on and then clicks into place, the same place, every single time you take it on and off? If so I bet it takes some time to do, whereas drilling and broaching an oversized hole, and letting the epoxy make a perfect fit is alot easier/quicker. I can fit up a multi-piece wa handle in less than 30 minutes this way. It's just one of hundreds of ways to fit up a tang


HSC /// said:
Thanks for the explanation but I don’t understand what is meant here...
I can get perfect fits with my tangs and handle depending on the construction method and I’m inquiring because I don’t understand why bedding a tang is done and I’ve never needed to do it.
Click to expand...
 
Skiller1nc said:
Can you get a perfect fit by broaching and filing a slot for the tang? A fit so perfect that the handle slides on and then clicks into place, the same place, every single time you take it on and off? If so I bet it takes some time to do, whereas drilling and broaching an oversized hole, and letting the epoxy make a perfect fit is alot easier/quicker. I can fit up a multi-piece wa handle in less than 30 minutes this way. It's just one of hundreds of ways to fit up a tang
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No, I cannot. I don’t make handles that way because it’s not efficient, for me

however I can get a perfect fit with a frame handle construction and that method is very efficient.

I can also do it by splitting the block and cutting like a mortise slot

I think I understand... so you have a block of wood and you make an oversized hole and then you fill it with epoxy to create a bed for the tang?
 
There's multiple reasons. Some guy want to be able to remove the blade but still have it tight enough to lock into placed and not move at all during use. Think knock down handle or wa.

I assemble my wa handles as a square block. I do this with the blade in place but I want to be able to remove my blade so I can shape the handle off the blade.

 
Tai Goo had a good write up on how to do the bedded tang. You probably can find it on his blog.

I have done it many times and it always works.
 
In a number of Karl Andersen's take down videos, you can see his handles fit very well with no bedding.

Here's one of his vids from 7 years ago that I'm aware of where he shows how it fits by itself on the tang @3:07 min:



I'm pretty sure he does all of his knives this way, so it is possible fit the handle nice and snug in an efficient way if you get your process down. I don't mean to imply there's anything wrong with bedding a tang in a handle, but only that it's not necessarily needed to great a great handle fit-up.

~Paul
My Youtube Channel
... (Some older vids of some of the older knives I made)
 
coldsteelburns said:
I'm pretty sure he does all of his knives this way, so it is possible fit the handle nice and snug in an efficient way if you get your process down. I don't mean to imply there's anything wrong with bedding a tang in a handle, but only that it's not necessarily needed to great a great handle fit-up.
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Oh, trust me, I know. I'm sure at some point in the future I'll move away from bedding the handle, but currently I'm trying to streamline things a bit and the prospect of drilling a hole and broaching it out a little bit and filling it with epoxy is just so much easier and less of a pain than carefully broaching the hole out to fit perfectly. I've also been meaning to mess around with frame handles for the same reason.
 
i do the vaseline first. i keep the dixie cup i mixed my epoxy in on the bench. when it is just slightly hard, a bit harder than jello by touching it with my finger, i pull the handle off and coat the tang with mineral oil using my finger and push the handle back on. pull it off every 2 hours. i have not had one get stuck yet.
 
Maybe a stupid (ignorant?) question .... but why would one want to be able to remove a handle? Especially with the Wa style, there would not be the threaded bolt on the butt to hold it securely (like on Karl Anderson’s knife .... which is beautiful...)
 
Cushing H. said:
Maybe a stupid (ignorant?) question .... but why would one want to be able to remove a handle? Especially with the Wa style, there would not be the threaded bolt on the butt to hold it securely (like on Karl Anderson’s knife .... which is beautiful...)
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It's just to remove the handle for shaping and finishing. You can shape the handle off the knife to avoid scratching the blade, yet you can fit it to the knife as you shape to make sure the handle looks how you desire. Once it's complete you add a little more epoxy and glue it in for good or use some beeswax so that if down the line the handle needs to be replaced it can be removed with heat.
 
Skiller1nc said:
It's just to remove the handle for shaping and finishing. You can shape the handle off the knife to avoid scratching the blade, yet you can fit it to the knife as you shape to make sure the handle looks how you desire. Once it's complete you add a little more epoxy and glue it in for good or use some beeswax so that if down the line the handle needs to be replaced it can be removed with heat.
Click to expand...
Hmmmm. So far I have not sensed any problems with dry fitting (without epoxy) As i shape the handle, and then doing the final glue up just once. Getting the alignment right is putzy enough without worrying about something changing (even a little) when the tang is pulled out. Then again, there is clearly a reason people are doing the fit this way ... so I will need to keep an eye out for problems, and keep this technique in mind. Thanks for the clarification
 
Another advantage to consider is that wood and other natural materials can swell up slightly depending on the humidity level or the dryness in the air. Gflex won't swell. I have heard some knife makers say they like to bed the tang for this reason. In the past they would get a "perfect" tight tang fit up from drilling and broaching, then something would cause the wood to swell and it would cause issues. I bed the tang for this reason and for the speed factor.
 
I also bed my kitchen handles, I like to shape them off the knife, especially if there are some funny transitions on the handle or something new I am trying. If it doesnt work out you can just do a new handle and not mess with getting the old one off.

I admit it is not efficient, since you need to glue up twice.
 
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