Hard work down the drain (Updated)

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lloydxmas250

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Apr 5, 2013
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So I was well into assembling a fillet knife that was to be a gift for my father-in-law. I applied epoxy today and I don't know what happened but the first side I epoxied hardened extremely fast even though I was working with epoxy with a 30 minute work time. The second side went flawless. I didn't realize it had hardened until after I clamped both sides together and even with the most pressure I can deliver without harming the scales, there is a small but unsightly gap between the scale and spacer.

This went from being a gift I was going to give in 2 weeks, to a very ugly, in my opinion, knife I'll keep around my house and not show off. Now I'll have to start over and the gift will be quit late.

I still can't figure out what went wrong. I was well under 30 minutes when I tried clamping the pieces together. In fact I was probably under 15. I did notice that the epoxy for the bad side was slightly more tacky than the second half but I didn't think it was so tacky it would create that gap. I put out the first bit of epoxy, mixed it well like I have in the past and it was tacky. The next side I put out the same amount and mixed it the same way and it was fine.

I'm pretty upset about this especially because everything was shaping up so well. I doubt there's anything I could really do and by the time I clamped it up the epoxy and the pins already had a good grip so I don't think I could have taken it apart and tried to get the epoxy off. Anyone with more experience, feel free to let me know what I can do in the future to not screw up again.
 
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Subjecting the knife to about 200ºF should weaken the epoxy and allow you to remove the handle. Clean the bulk of the epoxy off the scales with sandpaper and follow with acetone. Once you have everything cleaned up, you should have another shot at it. Make sure that all your surfaces are free of oil or anything else that might impair adhesion. (I follow acetone with denatured alcohol). Also, make sure you are mixing your epoxy in the correct ratio.
 
lloydxmas250 said:
So I was well into assembling a fillet knife that was to be a gift for my father-in-law. I applied epoxy today and I don't know what happened but the first side I epoxied hardened extremely fast even though I was working with epoxy with a 30 minute work time. The second side went flawless. I didn't realize it had hardened until after I clamped both sides together and even with the most pressure I can deliver without harming the scales, there is a small but unsightly gap between the scale and spacer.

This went from being a gift I was going to give in 2 weeks, to a very ugly, in my opinion, knife I'll keep around my house and not show off. Now I'll have to start over and the gift will be quit late.

I still can't figure out what went wrong. I was well under 30 minutes when I tried clamping the pieces together. In fact I was probably under 15. I did notice that the epoxy for the bad side was slightly more tacky than the second half but I didn't think it was so tacky it would create that gap. I put out the first bit of epoxy, mixed it well like I have in the past and it was tacky. The next side I put out the same amount and mixed it the same way and it was fine.

I'm pretty upset about this especially because everything was shaping up so well. I doubt there's anything I could really do and by the time I clamped it up the epoxy and the pins already had a good grip so I don't think I could have taken it apart and tried to get the epoxy off. Anyone with more experience, feel free to let me know what I can do in the future to not screw up again.
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Epoxy is not forever, You don't have to toss it completely.

Put the handle side into a boiling pot of water, it will free up the epoxy, but not overheat the blade.

Try again.




It takes lots of mixing to have epoxy properly mixed, and if you have a small scale you could weigh the amounts to be sure you get equal amounts.
 
Drill out the fasteners and then put the knife in the freezer over night. Then take it out put the handle in boiling water. And then try to whack or pry off the scale. The bond just might break.

I have had 30 min epoxy break loose just taking them out to the river on a cold morning (Fly rod but caps)

Oh also make sure you are not gluing up with a fan blowing over the epoxy...Lesson learned :)
 
This came in a syringe that produces the same amount of epoxy and hardener, so that wasn't the issue. I used the remainder of one syringe and then used another for the good side. Both syringes were stored in the same spot in the same temp and both seemed to have the same consistency. So I don't know what caused this. I'll try boiling the epoxy now before it gets even harder. Any tips for getting epoxy out of the dimples I put on the inside of the scales?
 
You could try to drill the epoxy out of the scales or just drill new dimples.

The one tube of epoxy could have been older than the other one. Or the fact the first syringe had been opened could have possibly caused it to prematurely harden.
 
jawilder said:
You could try to drill the epoxy out of the scales or just drill new dimples.

The one tube of epoxy could have been older than the other one. Or the fact the first syringe had been opened could have possibly caused it to prematurely harden.
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That makes sense about the epoxy being harder e cause the one tube was older (at least purchase-wise). But they seemed to have the same consistency coming out and mixing. Just hardened way way too fast.
 
I have had some do that to me as well. It hardened in the mixing pot before I even had the chance to use it. It got super hot too. Avoid extreme heat when working with epoxy. Our Yankee friends don't have to worry about heat all that much but down south, heat can really cause epoxy to harden faster than it should.
 
The time given on epoxy is a fictitious time....not the working time. 30 minute epoxy has about 6-10 minutes safe working time. 5 minute epoxy starts to set in 1-2 minutes. It may still feel sticky, and gel-like, but any work done past the setting point may result is a poor bond as well as improper fit.

Jut take off the handle and make a new one.

I personally rarely use epoxy of less than 24 hour cure time. That has 3-4 hours work time, and a much stronger bond. I consider 60 minute epoxy fast set.
 
This is one of my fears as a newb. I have one right now that I'm not sure if I totally like how the handle is coming out and I am at the point where I either have to scrap it or go ahead and epoxy it. Maybe it feels this way because I'm new but the epoxy part feels kind of like the point of no return :)

Let us know how it turns out.
 
jawilder said:
I have had some do that to me as well. It hardened in the mixing pot before I even had the chance to use it. It got super hot too. Avoid extreme heat when working with epoxy. Our Yankee friends don't have to worry about heat all that much but down south, heat can really cause epoxy to harden faster than it should.
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I'm starting to think that could have been it. I was working in my garage and it was a pretty warm Arizona day today.

Well I managed to get the scales off. I trashed the spacers but had enough extra to make another set. I cleaned the scales as best I could but the process in removing the scales left them looking a little water damaged (I'm hoping that it's just a thin layer that will sand out.) the process also bowed the scales ever so slightly so I had to re-flatten them. I worked faster and made sure the garage was cooler and no issues this time although it did start getting slightly tacky toward the end again.

So my issue is the epoxy. I like the cost of the 2 ton devcon epoxy but I'm not liking the little work time. Is there another epoxy out there that won't break the bank and is easy to mix correctly? Otherwise I'll just have to learn to work faster during this stage.
 
Ive had that happen when mixing too much expoxy in the little clear measuring cups. Gets really hot and set up like right now.

I have been using the 30 minute stuff from pops with good luck, but i just tried the gflex exopy, and that stuff is incredibly tough! I made a handle for a junk knife, (hidden tang with guard and one pin) and did the glue up with the gflex, waited a couple days, and then destroyed the handle to see how the epoxy did, and it was the best epoxy i have worked with.

The gflex says 45 minute pot life. And when it cured it was hard, yet had a little give to it. Amazing stuff
 
Tips on using epoxy and other resins:
1) Mix in a small cup, and then pour out on a sheet of waxed paper ( or a wide bottomed container) when ready. It will cure much slower in a thin puddle than in a cup with more depth. It has to do with the exothermic chemical reaction that sets the resin.
2) Get everything done and ready BEFORE mixing the resin. The blade should be clean, the paper towels and all supplies ready, and all parts test fitted first. Lay out the parts in exact order.
3) Wear Nitrile gloves. They can be pulled off and switched quickly if epoxy gets on them.
4) Tape up the blade to about 1/4" from the handle area.
5) Grind a small depression on the back ( inside) of the scales, or on the tang, that will make the scales only sit tightly to the tang along the edges. This makes for a better fit as well as providing an "Epoxy Reservoir" under the scales. It is very easy to squeeze out all the resin if the scales and tang are both flat. The contact perimeter surface only needs to be about 1/8" wide, and the hollowed out depth only needs to be a few hundredths of an inch.
6) Making the tang holes about 150% the size of the rivets/pins allows for easier fit-up and adjustment when putting in the pins. 1/8" pins should have a 3/16" tang hole, etc.
7) Only clamp with enough pressure to ensure the scales sit snug to the tang. DO NOT CLAMP HARD. This can cause the scaled to lift at the ends or edges, and can squeeze out all the resin, leaving practically nothing holding the handle on.
 
Well it seems to have set nicely this time. No abnormal gaps like last time. I'll wait a little longer and then get to shave down the pins.

Thanks for putting up that mini tutorial on epoxy. There's some good info. I do a lot of that stuff or stuff real similar. I drill dimples into the scales and holes through the spacer. The tang's middle and last hole were oversized a produce a large space for epoxy. I also shave a groove into the middle of the pins so the epoxy can grip on tight. I doubt I'll have problems with the epoxy strength on a fillet blade anyway.

Thanks everyone for the tips although I still think my final product my be diminished because of the mistakes. We'll see.
 
lloydxmas250 said:
Thanks everyone for the tips although I still think my final product my be diminished because of the mistakes. We'll see.
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It'll only be diminished if you allow it to be. It'll surely take more work cleaning/refinishing metal/reflattening scales/etc but if you hold your work up to your original standards then everything will turn out fine. Keep at it and don't settle for sub par quality. Good luck.

Btw, Stacy's advice on pouring the epoxy out on something flat really helps. I don't even mix in a container any more. It takes some practice but you can mix it well on a flat surface as long as you use something wide and flat to mix.
 
I have been using the plastic lid from some food container. Could be margarine tub, Chinese soup container, etc. I mix it on the top and after it has hardened, I flex it and peel off the remains and it is ready to use again. If it doesn't release just use a new lid.
I also use to mix on two pieces of duct tape which I would throw away after it hardened. I keep the mixed epoxy for a while to judge the hardening time.
Fred
 
When they say mix for a minute, they mean it. Almost any problems I have had with epoxy, regardless of price have been related to prep, or mixing. That said, I took everyone's advice before I actually making anything to sell and bought a good 24h epoxy at a local plastic/carbon supply. It has an extended heat range and is therefore less affected by cold than the store bought stuff.
 
Where I live in South East NM my shop gets warm in the summer. I used to use Conap Epoxy. To keep it from setting up too soon, I would put the epoxy in the refridgerator to cool it down before I would use it.
Since I have been using G-flex , I have not had that problem.
 
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