Epoxy

J

Jwgriesser

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What is the strength differently between 5 minute and 24 hour epoxy? I am using it to put on knife scales. Are other products to use?

Thanks for any advice.

Jay
 
You will hear folks say that the slower setting epoxies, like g-flex, are the best. This is true. On the other hand, I know a lot of folks that use Devcon 5 minute and haven't had any problems. I use corby bolts on all of my knife handles. I used to use Devon but have switched to G-flex just recently. I like how fast the Devcon sets up because I can glue up and shape the handle in the same day but think that the G-flex is the better option. My opinion is that if you use a mechanical fastener like corby bolts, mix your epoxy correctly, and have clean working surfaces then the Devcon will work fine. It's cheap and can be picked up locally. With that said, the slower setting epoxies are better.
 
I along with many others use Acraglas. It's a 24 hour epoxy used to bed rifle stocks. This stuff is tough. The only way to get a handle off after you've used it is to either smash it into pieces or heat it with a heat gun and try to pull the handles off. I never tried the G-flex but I've heard it's really really good also.
 
I really like G-flex. It is easy to mix. It has a one to one ratio. Some epoxy has a 2-1 ratio. I like the 1-1 ratio better. G-flex does a great job.
 
I've used Gorilla 5 minute epoxy with fine results, acraglass which I really like, and I just tried one with zpoxy, which is thinner than the others, but seems to have worked well.
I was going to ask if anyone has more long term experience with zpoxy?
 
In my opinion all epoxies will make a decent bond up front. Its down the road that is the problem.

If you dig hard enough you will find threads from long time makers explaining how they thought 5 minute epoxy was fine until five or so years down the road many of their knives came back falling apart. I know Ed Cafferty had this problem and did a great deal of research on the subject and now only uses top of the line stuff.

I don't recall the exact science but it is also out there if you want to know. If I remember correctly the chemical makeup that allows the epoxy to cure faster also compromises its integrity in the long term. The guy who just made blade bond went into great detail explaining this.

That and good epoxy is really not that expensive so why cheap out to save a few bucks only to have your knives returned or your reputation tarnished a few years down the road.

Acra glass, G flex, West Systems - All good stuff

-Clint
 
I used West System 105 and 205 or 206. I add my own colloidal silica filler as straight resin/handener with no additive is not the ideal adhesive according to the late John White who had a LOT more lifetime experience with the stuff building boats than making knives. . It is formulated more for laminating. The downside is that the pump dispensers meter out a lot more than you will ever need for one knife, so there is waste unless you do the PRECISE measurement of the two components with say small syringes.
 
West Systems epoxy and Brownell's Acraglass both work well for scale type handles. Acraglass
is thinner, and therefore more pourable......more easily useful for narrow tang construction.
 
jdm61 said:
I used West System 105 and 205 or 206. I add my own colloidal silica filler as straight resin/handener with no additive is not the ideal adhesive according to the late John White who had a LOT more lifetime experience with the stuff building boats than making knives. . It is formulated more for laminating. The downside is that the pump dispensers meter out a lot more than you will ever need for one knife, so there is waste unless you do the PRECISE measurement of the two components with say small syringes.
Click to expand...

They sell very cheap small digital scales now for the dieters and the drug dealers

Very handy for this kind of stuff.
$20 ish

but you have to use the weight ratio, not the volume ratio
 
its by volume according to West System. The West pumps give you a 5-1 ratio when using 105 and 205 or 206 hardeners. It is 3-1 for the 207 "clear coat" and 209 super slow hardener. That means that you need to make sure that you have the correct pump. I used the 205 for ages, but now I have gone over to the 206. I saw a your tube video where the guy was using the non-junkie little kid medicine syringes from Walgreens to good effect.
12345678910 said:
They sell very cheap small digital scales now for the dieters and the drug dealers

Very handy for this kind of stuff.
$20 ish

but you have to use the weight ratio, not the volume ratio
Click to expand...
 
Last edited:
The one instance where i had wanted better "pourability" was with some very nice wa handles that I bought where the slot in the ferrule was super narrow as it should be but the handle had a larger hole in the main part that had to be filled. Bubbles mess with you in that application. A doweled handle would help with that issue.
Russ Andrews said:
West Systems epoxy and Brownell's Acraglass both work well for scale type handles. Acraglass
is thinner, and therefore more pourable......more easily useful for narrow tang construction.
Click to expand...
 
Joe.....Sounds like you're referring to a blind tang with a spacer...not a ferrule.
I seldom use blind tang construction anymore....Prefer ferrule (ring around handle material),
and through tang construction.
Acraglass is poured in from the butt, and the cap threaded on to seal and mechanically attach...
Pourable makes a big difference there...
 
12345678910 said:
They sell very cheap small digital scales now for the dieters and the drug dealers

Very handy for this kind of stuff.
$20 ish

but you have to use the weight ratio, not the volume ratio
Click to expand...

I laughed count :) ... I use a drug dealer scale to measure my epoxy as well. Less messy than pumps and syringes imo.
 
jdm61 said:
The one instance where i had wanted better "pourability" was with some very nice wa handles that I bought where the slot in the ferrule was super narrow as it should be but the handle had a larger hole in the main part that had to be filled. Bubbles mess with you in that application. A doweled handle would help with that issue.
Click to expand...

On narrow tang slots I have used g Flex epoxy. It is initially way too thick, but apply a little bit of heat from a heat gun and it thins right out. Adding heat decreases your working time with the epoxy, so you have to finish pretty soon after pouring it in.

I'm sure acraglass is better for this type of tang, but I find it easier sticking to one type of epoxy that I'm familiar with.
 
Russ, these were handles made by Stefan Keller in Hawaii. He drilled a big "hole" in the main part of the handle, but routed a tiny slot for the tang in the "ferrule". They were made to have a tight fit of the tang and epoxied up and not to be filled with sawdust and charcoal and burned in like the common magnolia wa handles. The bubbles would hang in the slot and I had to tamp it down with a Starbucks swizzle stick. That is not a big problem but for the fact that I was using the faster curing 205 hardener. Hence my switch to 206 of late. :D like I said, the slotted dowel method of construction would solve that as you would need very little epoxy to do the job. I intend to try that in the near future.
Russ Andrews said:
Joe.....Sounds like you're referring to a blind tang with a spacer...not a ferrule.
I seldom use blind tang construction anymore....Prefer ferrule (ring around handle material),
and through tang construction.
Acraglass is poured in from the butt, and the cap threaded on to seal and mechanically attach...
Pourable makes a big difference there...
Click to expand...
 
jdm61 said:
its by volume according to West System. The West pumps give you a 5-1 ratio when using 105 and 205 or 206 hardeners. It is 3-1 for the 207 "clear coat" and 209 super slow hardener. That means that you need to make sure that you have the correct pump. I used the 205 for ages, but now I have gone over to the 206. I saw a your tube video where the guy was using the non-junkie little kid medicine syringes from Walgreens to good effect.
Click to expand...


They publish the ratio by weight or by volume, take your pick, weight is easiest for me.
http://www.westsystem.com/ss/assets/Product-Data-PDFs/TDS 105_205.pdf

Mix ratio by volume (300 Mini Pump ratio) ................ 5 parts resin : 1 part hardener
by weight ................................................................................................ 5.19 : 1
 
I have done some epoxy/fibreglass work on a couple Kayaks in the last year. Used West system 105 epoxy resin with 205 and 206 hardener. Are you guys saying this is the same stuff I can use for my knife handles? That would make things way easier.

I have some 5 min and 2 hr epoxy and I notice a difference in how hard the left overs are in my cup and on my applicator. The 5 minute stuff is quite hard and brittle...comes off the plastic applicator and cup relatively easily. The 2 hr epoxy is a bit flexible and not brittle and doesn't come off the plastic applicator and cup easily.

I bought a scale that would measure grains for weighing arrow components and arrows to get consistency with archery. Couldn't understand why there were about a thousand of these scales on ebay. My wife finally pronounced me dumb and explained that dealers used them and the police would likely show up at our house now because I was so clueless.
 
West systems G flex for me , apart from the peace of mind of using a quality product i like the fact that you have the time to work getting the fit up right with out rushing.

For narrow slots on a hidden tang i use a syringe with a straw glued to the end , the straw will fit into the narrowest of slots and down to the end of your tang hole, pull the straw out slowly as you inject the epoxy.
Normally i just make up a few for the next job(s) with any left over epoxy

epoxy%20syringes_zpsl4qrdbax.jpg
 
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