epoxy

One big improvement in installing a handle is creating a glue reservoir. Put a rough hollow grind down the center of the tang where the scales will be. Put a similar hollow on the scales. These don't need to be deep, a few thousandths is all you need. This way there is always a layer of epoxy between the scales and tang. One issue with clamping scales on a knife is squeezing all the epoxy out of the joint. This is called a "Glue Starved Joint". It is very weak and merely dropping the knife on the floor or countertop can pop a scale off. I also drill extra holes through the tang to create "epoxy bridges". These also strengthen the handle a good bit.
Also. the tang and scales don't need a fine grit surface. 120 grit is perfect. I carry the blade finish back just past the front of the handle.
 
If interested, here's alot of good info:

Adhesion: Making Handle Scales Stick, and Stay Stuck, on Blade Tangs

My previous posts on another thread led to the conclusion that I should consolidate this discussion into a single thread. I have had time to type out more on this subject - and so am posting this. I am also re-posting the earlier material so that it is all in one place eventually. Apologies...
www.bladeforums.com www.bladeforums.com
I'd suggest checking out the stickies at the top of the forum too.
 
Britt_Askew said:
I did some testing back when I first started and if I made sure the steel was real clean before applying the epoxy I could beat the shit out of it with a hammer and it would hold up fine but if the steel was not perfectly clean ( scale, decarb) it didnt take much to knock it loose. That said I would still use some kind of pin / mechanical fastener and not depend on just epoxy.
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Did you use acetone for cleaning the steel?
 
Michael Black said:
Depends on what you're doing with the knife. I make plenty of knives with only epoxy for a hidden tang construction. But most of them I use a pin. If it's a particularly hard use knife I'd recommend some sort of mechanical fastener in addition to the epoxy, like chicago screws, corby bolts, or loveless bolts.
Click to expand...
I purchased a 6 pc Steak Knife Kit (SK-SK6PCKIT) from WoodCraft which requires me to supply the knife scale material 3/8" x 1" x 5". This will be my first attempt at making scales for knives. The wood I have purchased is Black Palm which is 2020 on the Janka Hardness chart. Even though it is quite hard it is splintery so I need to stabilize it. I've just finished making my first vacuum chamber and I'm in the process of stabilizing it. I would love not to have to use the pins that came with the kit. I'm looking for a pin-free look. After researching epoxies for knife scales I've settled on J_B Weld #50165 which offers a temperature of up to 550 degrees with a tensile strength of 5020 psi. Seeing that I could have purchased top-of-the-line steak knives twice over for the investment I've made on this project I would prefer not to blow it. So I'm reaching out for the experience you folks are willing to share with me with hopes of a set of steak knives that will make me proud.
 
boneonbone said:
Did you use acetone for cleaning the steel?
Click to expand...
No, just straight from the grinder. That was a decade ago. I do now use denatured alcohol to clean the blade before gluing.
What type of pins came with your kit? If I was going to make a knife with those scales I would use black g10 pins , they wouldn't stand out like metal ones would.
 
I recommend G-Flex 2 part epoxy 24 hour cure (West Marine usually has it in the stores) over JB Weld. I found the JB weld had issues with adhesion when cold (like 30 degrees.)
 
Acetone you can get from a hardware store nowadays is filthy. It will leave a film behind. If you don't believe me, clean a piece of glass and let a pool of acetone evaporate on it. Use something like 90% isopropyl alcohol from the pharmacy and a clean cloth that hasn't seen Downey or something. No paper towels - they contain emollients and other leachables, too. Hit it with a hair dryer for a moment or leave to hang dry. Then glue. Don't trust any solvent in cans for this particular application which requires the utmost of cleanliness. Give yourself your best chance of success.

Having used acetone every day in my professional life I could not believe the crap quality of the stuff they put in those cans called "acetone for cleaning" when I re-opened my shop 2 years ago. This stuff sucks. It is much worse than even a dozen years ago.
 
fitzo said:
Acetone you can get from a hardware store nowadays is filthy. It will leave a film behind. If you don't believe me, clean a piece of glass and let a pool of acetone evaporate on it. Use something like 90% isopropyl alcohol from the pharmacy and a clean cloth that hasn't seen Downey or something. No paper towels - they contain emollients and other leachables, too. Hit it with a hair dryer for a moment or leave to hang dry. Then glue. Don't trust any solvent in cans for this particular application which requires the utmost of cleanliness. Give yourself your best chance of success.

Having used acetone every day in my professional life I could not believe the crap quality of the stuff they put in those cans called "acetone for cleaning" when I re-opened my shop 2 years ago. This stuff sucks. It is much worse than even a dozen years ago.
Click to expand...
Alcohol is what I use as a final prep as well. I found 100% isopropyl on the shelf at ACE Hardware and wonder about it. It was by the gallon. I currently use 91% but will try the 100% once the roads clear up a bit.
 
Oldnretired said:
Alcohol is what I use as a final prep as well. I found 100% isopropyl on the shelf at ACE Hardware and wonder about it. It was by the gallon. I currently use 91% but will try the 100% once the roads clear up a bit.
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I'm going to say this without having tested any of it except the "acetone for cleanup" and "alcohol" mix (Ethanol/Methanol/MIBK), but I would not trust anything that comes in a can at a hardware store, especially if it says "for cleaning" or some such. What most of those are is like once-scrap acetone distilled crudely, leftovers from an industrial chemical process, and then sold to someone else to package as clean-up solvent. they're called "recovered" solvents. In effect, someone found a way to make money selling their garbage, a form of recycling.
For a critical application like cleaning a glue-up surface, I'd stick with something either meant for use as a laboratory chemical or else something meant to go on humans. That's why I suggested the 90% Isopropyl alcohol - it's at the local pharmacy. Another choice, you can get 95% reagent ethyl alcohol on Amazon, and once in a while a big liquor place may have taxed 100% lab grade ethanol. I don't think I'd even trust Everclear 190 to not have some stuff dissolved in it that stay behind when it evaporates.
Maybe I'm just too critical and picky because I worked with all this chemical stuff.
 
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fitzo said:
I'm going to say this without having tested any of it except the "acetone for cleanup" and "alcohol" mix (Ethanol/Methanol/MIBK), but I would not trust anything that comes in a can at a hardware store, especially if it says "for cleaning" or some such. What most of those are is like once-scrap acetone distilled crudely, leftovers from an industrial chemical process, and then sold to someone else to package as clean-up solvent. they're called "recovered" solvents. In effect, someone found a way to make money selling their garbage, a form of recycling.
For a critical application like cleaning a glue-up surface, I'd stick with something either meant for use as a laboratory chemical or else something meant to go on humans. That's why I suggested the 90% Isopropyl alcohol - it's at the local pharmacy. Another choice, you can get 95% reagent ethyl alcohol on Amazon, and once in a while a big liquor place may have taxed 100% lab grade ethanol. I don't think I'd even trust Everclear 190 to not have some stuff dissolved in it that stay behind when it evaporates.
Maybe I'm just too critical and picky because I worked with all this chemical stuff.
Click to expand...
I get it and agree with the acetone being crap nowdays. I usually use brake cleaner followed up with alcohol.
Still think I'll experiment with the 100% isopropyl on glass and see if I can discern any residue?
 
Oldnretired said:
I get it and agree with the acetone being crap nowdays. I usually use brake cleaner followed up with alcohol.
Still think I'll experiment with the 100% isopropyl on glass and see if I can discern any residue?
Click to expand...
I'd love to hear your results from that test, please!! And, if it comes out good stuff, please post a photo of the can. Thanks and good luck with it. Hope it's clean.
Brake cleaner is a good choice, too!
 
boneonbone said:
I purchased a 6 pc Steak Knife Kit (SK-SK6PCKIT) from WoodCraft which requires me to supply the knife scale material 3/8" x 1" x 5". This will be my first attempt at making scales for knives. The wood I have purchased is Black Palm which is 2020 on the Janka Hardness chart. Even though it is quite hard it is splintery so I need to stabilize it. I've just finished making my first vacuum chamber and I'm in the process of stabilizing it. I would love not to have to use the pins that came with the kit. I'm looking for a pin-free look. After researching epoxies for knife scales I've settled on J_B Weld #50165 which offers a temperature of up to 550 degrees with a tensile strength of 5020 psi. Seeing that I could have purchased top-of-the-line steak knives twice over for the investment I've made on this project I would prefer not to blow it. So I'm reaching out for the experience you folks are willing to share with me with hopes of a set of steak knives that will make me proud.
Click to expand...
If you don't want to blow it-use mechanical fasteners. Pins, Corby bolts, etc.
 
Britt_Askew said:
No, just straight from the grinder. That was a decade ago. I do now use denatured alcohol to clean the blade before gluing.
What type of pins came with your kit? If I was going to make a knife with those scales I would use black g10 pins , they wouldn't stand out like metal ones would.
Click to expand...
Can you tell me a little bit more of why you would suggest using g10 pins?
 
Stacy E. Apelt - Bladesmith said:
One big improvement in installing a handle is creating a glue reservoir. Put a rough hollow grind down the center of the tang where the scales will be. Put a similar hollow on the scales. These don't need to be deep, a few thousandths is all you need. This way there is always a layer of epoxy between the scales and tang. One issue with clamping scales on a knife is squeezing all the epoxy out of the joint. This is called a "Glue Starved Joint". It is very weak and merely dropping the knife on the floor or countertop can pop a scale off. I also drill extra holes through the tang to create "epoxy bridges". These also strengthen the handle a good bit.
Also. the tang and scales don't need a fine grit surface. 120 grit is perfect. I carry the blade finish back just past the front of the handle.
Click to expand...
I find all your advice makes sence, thanks.
 
Stacy E. Apelt - Bladesmith said:
One big improvement in installing a handle is creating a glue reservoir. Put a rough hollow grind down the center of the tang where the scales will be. Put a similar hollow on the scales. These don't need to be deep, a few thousandths is all you need. This way there is always a layer of epoxy between the scales and tang. One issue with clamping scales on a knife is squeezing all the epoxy out of the joint. This is called a "Glue Starved Joint". It is very weak and merely dropping the knife on the floor or countertop can pop a scale off. I also drill extra holes through the tang to create "epoxy bridges". These also strengthen the handle a good bit.
Also. the tang and scales don't need a fine grit surface. 120 grit is perfect. I carry the blade finish back just past the front of the handle.
Click to expand...
this idea of a 'glue reservoir'- I just don't understand how it makes for a stronger bond than two parallel surfaces. Particularly if there are pin holes going through it.
Would you explain how it creates a stronger bond? Do you have or know of any evidence of it being stronger?
 
Lorien said:
this idea of a 'glue reservoir'- I just don't understand how it makes for a stronger bond than two parallel surfaces. Particularly if there are pin holes going through it.
Would you explain how it creates a stronger bond? Do you have or know of any evidence of it being stronger?
Click to expand...
Lorien,
I have wondered this too. I think that the joint or extra space itself doesn't make the joint stronger but it allows for more epoxy to collect in the areas of adhesion (if that makes sense). The main benefit is preventing the glue starved condition that was mentioned. As long as there is an even coat between the objects (not dry), it should all be about the same imo. It's just a way to maybe aid in getting that condition....my 2 cents.
 
boneonbone said:
Can you tell me a little bit more of why you would suggest using g10 pins?
Click to expand...
Only for visual reasons. I think they would blend in and not stand out. Corby bolts would be stronger probably, but I use black g10 pins on most all my stuff and havnt had a failure because of pins.
Lorien said:
this idea of a 'glue reservoir'- I just don't understand how it makes for a stronger bond than two parallel surfaces. Particularly if there are pin holes going through it.
Would you explain how it creates a stronger bond? Do you have or know of any evidence of it being stronger?
Click to expand...
My first knives I would sometimes have a problem with squeezing all the glue out from clamping to hard , in woodworking which is where i came from, this was not an issue . Grinding a small cavity in the back of the scales and switching to some cheaper Chinese clamps that don't clamp as hard stopped my failures 🤷‍♂️
 
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