Epoxying question for you "seasoned" pros.

Retroguy said:
I've had an issue when cleaning the ricasso area with acetone and a Qtip it dissolves too much epoxy and leaves a small valley under the scale. What's the best way to clean that area?
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Use the broken end of a popsicle stick. The end will be splintered. It gets into the corners perfectly. Cover the splinters with a paper towel. Use 90% rubbing alcohol.
 
That's what I've been told..................but I've never been able to get Cyanoacrylate glues to glue shut an actively bleeding wound. Blood seeps around the edges of a butterfly strip.................at least both of those observations have been my experience. A Bandaid strip pulled tightly keeps me from bleeding all over my carving or my student's carvings. ;)
 
I'm sure that would work. The cuts we usually get in the carving class I teach at the Vo-tech are typically 1/8" to 1/4" long....................falling short to be worthy of anything like WoundSeal. But they can sure bleed all over everything. :eek: Had a woman in my class who was carving a low-relief carving of a Cardinal when she cut herself. Commented it would save her some red paint when the time came to paint it. ;)
 
Chris623 said:
Okay, Gentlemen, let me introduce my first wood carving knife................"Ebony & Ivory". It's actually a lot purdier than the picture, but I wasn't going to put together all my lighting equipment for a quick shot like this one. I've been at it a long time and I'm tired of messing with it. Since I'm not selling it, I probably won't take a better picture, but this one will give you an idea how it turned out. Not happy with the brown reflection on the blade and the brass, but that's what you get when you don't set up all your soft lights and tents, etc.

View attachment 68495
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That is very nice. Great job.
 
Chris623 said:
Thanks. I appreciate the accolades from you experienced knife makers.
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I feel like I should correct you, here. But... nah, you’re right, I’m just and old seasoned pro trying to help out beginners. Hehe.

In all seriousness though, that’s a very nice looking knife. It also looks like it would be a great carver. I might just have to make me one like that. Well done.
 
Am I approaching this wrong? Am I using the wrong Epoxy.
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I've tried to resist posting on this thread, for fear of being viewed as a "epoxy snob".... but I just would hate to see others make the mistakes I have. So, back to the original question(s).

If it's longevity you want (as in you don't want to see that knife again in 5-7 years because the epoxy you chose to use has broken down), Personally the only "glue" that I will use for assembling knives, is the original Acraglas from Brownells. It's different in that the mixing ratio is 4 parts resin, to 1 part hardener.... and you have to be pretty close to that when mixing. Unlike most 2 part adhesives that are mixed 50/50.....and some folks add a bit more hardener to get the "glue" to "kick" quicker........ if you put more hardener in your Acraglas mix, it will get to the consistency of 3 day old jell-o..... and never any harder.
Brownells sells graduated mixing cups to get you started, but you'll quickly get the knack for mixing it.
Here's the up side(s)..... Acraglas has a 10 year shelf life, and a 50 year hold life. Why is that important? Because most commercially sold 2-part epoxies (like you can buy in the local hardware store) has a shelf life of 6 months (from the date of production)..... and a hold life of 5-7 years. (that means the epoxy is chemically engineered to START physically breaking down in 5-7 years after it's mixed/cured.)

I've told my story a number of times on the forums, so I won't do it again here, but suffice to say, if you don't want to be doing a lot of repairs, or have your name smeared around because the knife you built for someone "fell apart", then pay particular attention to the "glue" you choose/use.

When it comes to heat, most of the "cheap" epoxy products will "let go" in the 250-300F range. Acraglas is slightly better....it will let go in the 375-450F range. That being said, it's not a good idea to get any of it "hot".....you're just shortening it's hold life.

I've been at this a long time, and have been a "tester" for a number of the available "epoxies", and frankly, after testing them in my shop, I wouldn't touch most of the popular brands with a 10 foot pole. Whenever I've been asked to "test" product(s), I tend to ask a lot of questions.....and if they can't give me a shelf life, and/or a hold life that meets or beats Acraglas.... I politely decline. If they can't offer me better performance than what I'm already using....what's the point?
 
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Well said, Ed. I ordered Acraglas from Brownell's a couple of days ago, I think. It's on back-order, though. But after talking with a lot of people both on-line and off, I tend to agree with you.
 
So if it has a 50 year hold life does that mean that the handle will need replaced in 50 years? Of course that is a looong time, way longer than any of my knives at this time will last. Just wondering. Thanks!
 
Wow. Now I'm worried my knives will come flying apart because I used 5-minute epoxy from Menards and cleaned with acetone before gluing... Thanks for the advice Ed and Boss! Guess I better step it up if I want to run with the KDogs!
 
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Daniel Macina said:
Does anyone know the hold life on West systems epoxy can’t find it if they have it listed?
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It’s used to make boat hulls that will see a thousand times more stress and fatigue than any knife handle will ever experience. Fiberglass boats from the 60s (especially sailboats) still fill every marina in the developed world. And that’s 1960s resin when it was a new concept and nobody knew anything about it. I have cut holes in 1960s hulls that are every bit as solid as a brand new hull. Where you see hull problems are with air bubbles and poor bonding to core materials. (Most hulls are a sandwich.) But properly laid glass from 50 years ago is still bonded to wooden structural members like the day it was laid.

GFlex 650 is on a whole new level from that. It is a toughened epoxy that will actually flex under shock loads instead of fracturing. When I see sailboats rounding the capes in unimaginable weather I don’t lose sleep over my knife skinning a deer or chopping cucumbers. If I did worry I’d use corby bolts instead of pins and go back to sleep.

I’ve made mistakes on a couple handles where I got in a rush and put the liners on out of order. Of course I didn’t notice until the handle was cured and I had shaped it, which meant I had to take off the handle and redo it. Nothing I did would make the G-Flex let go. I boiled the knife. I froze the knife. Nothing. I realized I would have to destroy the handle so I decided to see what it would take. I drilled out the pins. I beat the handle with a hammer. I chucked the blade in a vise and grabbed the scales with my biggest channel-lock pliars and tried to break the scales off. All it did was chew up the wood.

I finally took the knife to the grinder. What I found was that the scales, liners, and tang were basically fused into a mono-block. I had to grind the tang back to bare metal because even the streaky remnants of the fiber liner couldn’t be scraped off.

Now, granted this was a newly handled knife. As to the epoxy breaking down over time, I refer back to boat hulls. Can epoxy break down? Yes it can. Most of the time it’s due to UV light damage to cheaper polyester resin. True epoxy is a different animal than polyester resin and the price reflects that difference. Are all epoxies the same? No. But a lot of the difference goes back to being a fast-cure versus a slow cure formula, too.

Boss made a key point. Surface prep is probably the biggest factor. You find that to be true in boatyards everywhere. Bad fiberglass jobs fail regardless of the type of resin. Epoxy bonds via chemical reaction. Residue, bad mix, too much squeeze out leaving the epoxy too thin- all of these things change the reaction.
 
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So if it has a 50 year hold life does that mean that the handle will need replaced in 50 years?
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That means that you have AT LEAST 50 years before it STARTS to chemically break down.

Does anyone know the hold life on West systems epoxy can’t find it if they have it listed?
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I've never seen it listed. The way I found out was calling and talking to the "tech dept". I was told "The minimum hold life on any of our products is 20 years".

Now I'm worried my knives will come flying apart because I used 5-minute epoxy from Menards
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I doubt anything will "fly apart". What I found when all the problems came tumbling down on me, is that the epoxy started turning into a powder, and the handles slowly loosened over time....some much worse than others.....but it cost me a LOT of time repairing/replacing things, and a LOT of heartache, trying to make it up to customers.

AND.... DITTO to the last two paragraphs of John W's post!!
 
Sure am glad I asked the original question................I've learned a whole lot more than I expected to. You guys are great!
 
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