Recommendation? Epoxy that lets go with heat?

REK Knives

REK Knives

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Knifemaker / Craftsman / Service Provider
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I've been using blade pro... In my tests it's slightly stronger than gflex.

The problem is that when I wanna re-do something and remove a handle (from a hidden tang knife for example) it won't let go.

I heated a leftover cured sample I had up to 450f after trying to get a blade out of a hidden tang knife I made at 350f (wasn't working).

This stuff stayed hard and barely pliable at that temp even though it turned brown. When I called technical support for system three they said it's designed to be permanent and heat won't loosen it up.

Any body tried any tests with what you have/use?PXL_20230517_201125319.jpg
 
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I'm glad to hear this as I've been using Bladepro and hope that it's as tough as possible.

I guess if I felt I needed to redo a handle I would grind it off.
 
OK thanks for chiming in guys... If anyone has scrap/leftover epoxy that dries in a cup maybe you could send my way? (I'll pay for shipping) that way I can see how it reacts at different temps!
 
Is there some sort of hot melt glue you could use? A well fitted handle with a pin is mechanically locked, so the glue can just be used for a sealant.
Personally i just consider the handle scrap at that point and remove it with a chisel
 
Alex Topfer said:
Is there some sort of hot melt glue you could use? A well fitted handle with a pin is mechanically locked, so the glue can just be used for a sealant.
Personally i just consider the handle scrap at that point and remove it with a chisel
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most traditional knives were and are made using rosin which is heat moulded and sets hard. For knives where it's useful to be able to remove the handle relatively easily, (like back when good cutlery steel was hard to come by) it might be better to have something that loses its hold with some heat- not enough to ruin the temper, but enough that a knife wouldn't generally be exposed to
 
Sealing wax compounds were used by cutlers for a long time. It melts around 200°F. The stuff used most of the time was sealing wax and brick dust. It is what is in the handles of silver table knives.
 
Lorien said:
most traditional knives were and are made using rosin which is heat moulded and sets hard. For knives where it's useful to be able to remove the handle relatively easily, (like back when good cutlery steel was hard to come by) it might be better to have something that loses its hold with some heat- not enough to ruin the temper, but enough that a knife wouldn't generally be exposed to
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Yeah that's exactly what I'm after! I'll have to look that up
 
Here is a formula for Cutlers Resin: equal parts pinon rosin (pine pitch) and brick dust, plus 5-10% beeswax. Some recipes use sawdust instead of brick dust.

Another old formula used to mount sword handles was: Equal parts rosin, hide glue, saw dust.

A modern and probably better resin to use is lapidary dop wax. It is similar to what the cutlers used and comes in sticks like sealing wax. It is nused to hold stones while beimg faceted or cabbed.



Tips for filling handles:
When filling a handle with epoxy (or resin) getting it all over the place is a common problem. Tape up the handle and make a funnel with extra tape around the open end of the handle. This keeps excess from running over the sides, especially when you insert the tang. When the tang has been inserted, peel off the tape funnel and clean the end up.

When using any of the resin-based waxes to be poured put the broken chunks of hardened wax in a small bottle. Place the bottle in a pan of boiling water and let it melt. Pour into the handle recess from the bottle. When not in use just cap or cork the bottle.

A tip for getting the epoxy to run down the tang hole, especially on a thin hole like on a wa handle, is to insert a cocktail straw or hollow coffee stir. Push it to the bottom of the tang hole and pour in the epoxy. The air will escape up the straw and let the epoxy pour down the hole easily.

Last tip - Epoxy is thick and hard to pour down a tiny hole. Warm the epoxy mixing pot in a pan of hot water or give it a second or two in the microwave and it will get almost water thin. Caution - this speeds the set time, so use a slow set epoxy or it may set up o you too fast. I find the 24-hour epoxies do very well with warming.
 
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REK Knives said:
I've been using blade pro... In my tests it's slightly stronger than gflex.

The problem is that when I wanna re-do something and remove a handle (from a hidden tang knife for example) it won't let go.

I heated a leftover cured sample I had up to 450f after trying to get a blade out of a hidden tang knife I made at 350f (wasn't working).

This stuff stayed hard and barely pliable at that temp even though it turned brown. When I called technical support for system three they said it's designed to be permanent and heat won't loosen it up.

Any body tried any tests with what you have/use?View attachment 2189156
Click to expand...
What you show here is that epoxy you used is good. Why do you complain and looking for other epoxy ? I hope that you don t remove handles on every second knife you make :)
PS .In your test you heated epoxy too fast and that s why it get brown , you burned it . You need to heat epoxy very slow and maybe it will become enough soft to remove tang from handle ...........
 
Alex Topfer said:
Is there some sort of hot melt glue you could use? A well fitted handle with a pin is mechanically locked, so the glue can just be used for a sealant.
Personally i just consider the handle scrap at that point and remove it with a chisel
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If I can save handle would be better for me , I can make new blade faster and cheaper then new handle :)
 
I agree with Natlek. Slowly heating the entire knife to 200° in an oven for 20 minutes and then heating the blade gently with a torch to around 300° will make every epoxy I have used let go. You may have to twist and pull a but to get the resin to start to crumble, but it will come out.
 
REK Knives said:
Yeah that's exactly what I'm after! I'll have to look that up
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Your'e probably much better off using a high quality epoxy than anything else. Back when William Scagel was making knives every knife he made he most likely used cutlers resin along with at least one or two pins, Bo Randall's early knives were pinned with one or two pins as well. Once quality epoxies became available Randall Knives stopped pinning their handles, around 1957 or 1958. The cutlers resin by its self probably isn't reliable enough to hold a knife handle on by itself, so you will most likely need to pin it as well, then the handle will be nearly impossible to get off in one piece without damaging it. This is just my two cents.
 
Well just tested some CA glue and it let go pretty easy at 250f
 
Stacy E. Apelt - Bladesmith said:
I agree with Natlek. Slowly heating the entire knife to 200° in an oven for 20 minutes and then heating the blade gently with a torch to around 300° will make every epoxy I have used let go. You may have to twist and pull a but to get the resin to start to crumble, but it will come out.
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I basically did this... I started low and ramped up the oven 50° at a time letting it sit for 20-30 min at each stage.
 
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