What the...why isnt the epoxy working???

T

Taz

Knifemaker / Craftsman / Service Provider
Joined
Apr 28, 1999
Messages
2,494
THis is really ticking me off. I am making a folder kit, black/green G10 handles, brass liners. I am usin Devcon 2 ton epoxy, the waterproof and long setting one. The scales have popped off of the liners 3 times now. After each time, I clean up both the scales and liners to 220 grit, wash off and let dry, then epoxy and clamp and leave them for a full 24 hours. They seems bonded well, but when I drill out the hole that is for the locking bar that is filled with epoxy, shape or do anything to the handle, the scales pop off. I have used this same epoxy for several knives and have had no trouble. What is going on???
 
Taz,

Stab in the dark, but how tight are you clamping? Is there a distinguishable epoxy line? (Should there be?) Maybe you're squeezing all of the hold out of the epoxy.

Mike
 
I use the same product and I swear by it.

Here are some pitfalls to look out for:...

You are in snow country (I am in Sun Country -- Tucson...), make sure the material is all at a reasonable "room temperature". Your work area might have cold spots and if the liners and scales are cold, the epoxy will not be able to get a good "grip" before it starts to set. I would ensure all equipment, epoxy dispensers, liners, scales are at a nice working temperature, like 80 degrees F.

Another pitfall, is the mixing media. I use a piece of glass to mix the epoxy upon and add to dye (if used...), And I use a medical spatula to mix the epoxy. Then I transfer all the mixed epoxy to another piece of glass. I then mix some more, and then spread the epoxy from there. This way, I ensure I do not have any “rich” areas of rosin, hardener, or dye. In addition, I “butter up” everything, both the liner and the scale. Using cardboard or some other porous material may allow some of the hardener to be absorbed. Also, always use a clean mixing tool, using the same “nail or screwdriver” will cause the epoxy to start setting up while you are still mixing. The medical spatula I use is stainless steel, very flexible can be cleaned up very easily…

You’ve already said you clean up everything, but is it really clean? If you are using some type of soap, it might be leaving some film on the items. I wash everything down with dish soap (Dove) and really HOT water and then I do my final cleaning with Acetone.

When I apply the epoxy, I wear rubber cloves. Besides allowing me to be as sloppy as I wish, I do not have to worry about putting new fingerprints on it…

I hope this helps…

Bruce Jensky
 
I clamp until the handle doesn't move around. I usually dont clamp all of the epoxy out. This is the first time I had any problems with this epoxy. The temp is about 60, is that too cold to epoxy? Also, i use scraps of micarta I have laying around to mix with and I mix on a plastic yogurt container lid, a different one each time. I mix for about a minute or so, so the mix is pretty thorough. I have a heat gun, can I use that to warm up the liners and stuff and will the heat gun help the epoxy to set faster? It has 2 settings, I think the high one is about 1000 degree setting on the heat gun. I got the heat gun for kydex sheath making. I am going to go to the local hardware store and se what they have. they have a lot of epoxy and JB weld stuff, so I will see what they have. This is driving me crazy!!!!
 
I may catch some flak for this but try cyanoacrylate. Not the Crazy Glue brand but the stuff you use in woodworking. Crazy Glue is a little bit thick where the woodworking stuff is like water. Don't use an accelerator, it could cause the glue to bubble-up.

I have found with cyanoacrylate, the less permeable the materials are, the better. Both the scales and liners should be smooth. 220 is perfect.

You have about 2-3 seconds of work time with this stuff so make sure of your fit before hand. This sort of glue works cures best in the absence of air. You may have some liquid glue dripping out of the handle but the stuff inside is hard as a rock.

I have never used this on folders but have built several fixed blade, full tang knives. On the odd occasion that I have screwed up the handle for one reason or another, it's taken a hammer and screwdriver to smash off the handle material. It is very difficult to separate. I don't pin my handles until after they are shaped. I have never once had a slab pop off.

Sorry for being long-winded.

Hugh

PS; Epoxy all pins. Cyano can dry on you before you get the pin all the way into the hole.

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King of all that rhymes with Orange!
 
Taz,
More than likely the epoxy doesn't have anything to grab on to. You might want to take a dremel tool and cut some tiny grooves (not too deep and keep away from the edges) into both your liner and the scale material.
Once this is done the epoxy will be able to hold the scales on.

I have done the above on some lockback folders and it works great.

------------------
Barry
Jones Knives
"NEW Knives"
http://albums.photopoint.com/j/AlbumIndex?u=126319&a=5922856
"For DUTY and HUMANITY!"
Curly, Moe, & Larry
 
On the handle I just glued up I driled a bunch of 1/8"x1/8" holes on the face of the handle slab that fits against the tang these form epoxy "rivets" and I concentrated them where I had drilled weight reduction holes in the tang so they actually go from one side to the other. One bit of advice I read here before was to sand the surfaces like you did but only minutes before glue up. This was explained as creating an ideal surface for forming an adhesive bond at the molecular level. Who knows? Seems like I remember a post in here before where someone had some bad batches of epoxy and was experiencing similiar problems and this was with a brand he had used before with no problems. -Guy
 
You could have a bad batch of epoxy. Try it on something else. Get a new batch.

You could have problem with your substrate. When the joint comes apart where does the epoxy go. If it sticks to the metal, but not to the G10, maybe the G10 is contaminated. Clean the G10 with acetone then sand with new, clean, 220 Wet or Dry paper. Alternately clean and sand the metal if the epoxy sticks to the G10. If it comes off of both you have problem with the epoxy. If the G10 delaminates, you have defective G10.

You may just have problem with not allowing the epoxy to cure enough. Maybe the problem is the cold weather that has been hitting the nation. For maximum strength cure at around 100 degress F. This is easily done closely under a desk lamp. At 60 degrees you might need to wait for days for maximum strength.
 
Thanks, guys! I will try roughing up the liner more. The glue is stuck to the G10, and comes clean off of the brass liner, maybe the liner is too click and I need to rough it up, or maybe the lienr is too cold. I looked at the temp in the basement where I work, and it was 56, and upstairs is about 60 or 62 degrees, so it could be the temp is too low. My parents are stingy and hate to heat the house above 65 degreees, so i will wait till i go back to college and I will crank the heat up to 75
smile.gif
. I heard bout some bad batches of Devcon epoxy before. I went to the hardware store. They had Devcon 5 minute, JB Weld JB KWICK, Ace brand slow set and a super slow set from Ace True Value brand. I bought the Ace slow set stuff. Also, anyone here of PC-7 or -11? They had tubes of that, it is an epoxy paste. Anyone ever use it?

I used this batch of epoxy for a few knives and had no problem with it at all until now. Maybe the liner flexed a little and broke the bond, but it is supposed to be the 2 ton stuff, so that shouldnt have mattered.

i found the trays of epoxy that i used for the first 2 gluings, and they were still tacky, so maybe the stuff didnt harden enough becuase it is so cold here. But the stuff of the knife was always dry and hard, I didnt notice the scale coming off until I started working it a little.

Well, I will be bringing my Dremel, belts, files, sandpaper, bits, etc with me to college. Tom Anderson was gracious enough to offer to let me come visit, so i will bring it and see if he has any ideas.
 
Hey Taz...

I agree with Barry...

Really tear up the surface with a carbide cutter or something...
The rougher your surface area is the better...

Also George brings up a Very good point..

Try buying another tube from a different store..Good chance the entire lot is damaged

If it has been frozen,,Forget it,, it's Shot Big Time..

Also 60 degrees it a tad cool..

A little tip I use when glueing this is Duct Tape..

Lay a short piece of tape on your bench,then another overlapping it nicely..
Use this to mix your glue,, then just peel it off and pop it in the garbage...

ttyle

Eric...

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On/Scene Tactical
Leading The Way In Quality Synthetic Sheathing
 
taz,I also use Devcon 2 ton & found out that it works a lot better & lasts much longer if you store it inside your living quarters,=more consistant temp.,I live in an area that gets very cold in winter,hot hot in summer,I have had this stuff go bad when I kept it in the shop.Just one more thing to try.

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MJH
 
Oh great, I've been stockpiling the Devcon 2 ton stuff for the past year and storing it in my garage. WalMart carries the stuff cheap! Now I find out (and the package doesn't say anything about this!) that it's not good to let it freeze and Florida just experienced the two coldest months in a decade! Oh well, at least it's cheap and I didn't buy that many packages!-Guy Thomas
 
One other possibility that hasn't been touched on (or maybe I missed it) is that it is possible that you may be getting the scales too hot from grinding to shape AFTER they have been epoxied. I was having this problem at one time and was set strait on another forum. Just another thought......I never had this problem on fixed blades, only folders. The scales are much thinner.

Craig
 
How thick are the scales? No matter how well you glue the scales onto the liner, If you flex the liner doing any operation, they are going to pop off!
 
TAZ:

Don't worry - we'll get those overlays to stay put! I'll break out the thermoset epoxy, if necessary.
wink.gif


When do you want to come over?

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Tom Anderson
Hand Crafted Knives
 
Tom!!! Welcome back!!!! I dont start classes till weds, so I am free tomorrow or later on today and tonight. After that, I wont be free till the weekend. I will probably give you a call sometime this evening. I brought my box of tools and goodies and some designs I have been playing with. Talk to you soon!
 
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