2 ton epoxy

[Andrew Garrett]

I swiped this post of Tracy's from the Glue Wars thread. It represents a lot of testing and merits repeating here. Hope ya don't mind Tracy.
BTW When you make reference to Full tang handles below, I can't help but think you meant 'hidden' tangs such as stag where the epoxy is poured into the hole. Is this the case? I ask because right before you say Gorilla Glue should not be used for full tangs, you say that it was the best at gluing wood scales to steel. Typo?

Quote:

"I learned several things from these adhesive experiments.

First, I had been told over several years by very good knife makers, that Devcon 2 ton epoxy was a great choice for knife making. They had been told, no doubt by other great knife makers that it was great adhesive. Devcon 2 part epoxy was one of the very first adhesives to fail both Steve?s tests and mine. It rarely lasted more than a few cycles through the dishwasher. The learning here was: test and check every thing you?ve been told even if it comes from a very good source. Nothing beats an opinion more than testing it yourself. Given this, you probably shouldn?t believe another word that follows this one. I know I don?t believe half of what comes out of my mouth some times.

The second learning:
Surface preparation is more important to a successful glue up than is the adhesive its self. Please don?t underestimate surface preparation. A mediocre adhesive with an excellent surface preparation will out perform an excellent adhesive with a poor preparation by a large margin.
Steve diligently cleaned some of his test pieces with Simple Green, a soap that is often recommended for cleaning all kinds of things. The simple green apparently left a residue that prematurely failed all of his initial adhesive tests. Other surface cleaning solutions also left a residue that impaired adhesive performance.
My tests on a roughed up or scratched surface using a fresh 36 grit belt versus sand blasting gave exceptionally clear results. On ten test pieces I prepared, one end was sand blasted and the other scratched with a 36 grit belt, all of the scratched surfaces failed. Six of ten of the sandblasted surfaces survived. THIS IS HUGE. Again, routinely, high caliber and very competent knife makers recommended scratching or roughing up the surface of a knife to provide a better purchase for the adhesive. Certainly this is true but sandblasting a surface vastly out performs a scratched surface to the point where I recommend a knife maker absolutely invest in at least a minimal sandblasting setup to prepare a surface for glue up. Watch chemical cleaners for residue. Test this by allowing you cleaning chemical to dry on a piece of glass and have a look. I use isopropyl alcohol myself.

Third learning:
Read up on your adhesive. With the Internet, there really isn?t a reason you can?t completely understand what you are working with. Gorilla glue was being used or at least considered for use in full tang knives since it tended to expand as it cured. I thought this was a great feature of this particular adhesive. It also seemed to make this adhesive perfect use for a full tang knife. Fill the hollow in the handle material part way, put it together and let the expansion fill the rest of the hollow. The problem is that the expanded (foam looking) adhesive has no mechanical strength at all. This was documented fairly clearly on the Gorilla glue web site but had not been ?reported? to others on the forums as a caution. On the other hand, you can?t believe every thing you read. JB Weld failed most dishwasher tests and is reportedly good up to over 400 degrees Fahrenheit. They must mean a dry heat dishwasher.

Fourth learning:
There is no one perfect adhesive. There are some that work really, really well at some things but not at all things. Gorilla glue outperformed every adhesive in my destructive tests when gluing wood to metal. It failed miserably when gluing metal to metal or metal to Micarta. Loctite Speedbonder 324 held a stunning 100lbs of weight when bonding metal to metal but failed early gluing metal to wood.

Fifth learning:
Thicker glue is easier to use than thin glue. Viscosity ratings are impossible to relate to so I?d suggest the perfect viscosity is butterscotch pudding. Peanut butter consistency is too thick, syrup is to runny and messy. This makes such a difference that if a couple of adhesives are close in performance, the hands down choice would be to go with the butterscotch stuff. I hope I?m not being too technical.

Sixth learning:
There are some amazing adhesives out there. Amazing adhesives. Our recommendations can and probably should fall to the wayside over the next several years as adhesives technology continues to improve. They glue cars together now instead of welding or rivets. Cars!
Glued together! What the hell? Keep an eye open for new adhesives but make sure and test it.

Seventh learning:
Testing wasn?t all that hard. If you find a new adhesive you want to test, glue some wood to metal and throw it in the dishwasher for a half a dozen cycles. If it survives that, you might have something. If it doesn?t, don?t even consider it. If it makes it through the dishwasher tests, boil it for an hour or so. If it makes it past that test, you are really on to something. From there make something else up and let us know what you?ve found as you are probably on to a good one.

Eighth learning:
Industrial adhesives are generally better than adhesives packaged for retail sales to the general public. There are exceptions of course but it generally holds true. K&G epoxy, which is a recommended adhesive from our tests, is industrial epoxy ?repackaged? and marketed to knife makers and gunsmiths.

Ninth learning:
Gorilla glue shouldn?t have held up like it did. It was supposed to fail early and was just meant to bulk up the tests. It kicked most every other adhesives ass all over the block. Keep an eye out for things that aren?t supposed to work and try them out.

Tenth learning:
Steve found some adhesives I never would have. I found some he didn?t. Collaboration and sharing information helps the process. Not really a new learning but it?s worth repeating and it was clearly demonstrated here.

Eleventh learning:
There is a type of adhesive that cures by a lack of oxygen. I?d never heard of anything like it before. It?s called anaerobic curing adhesive and won?t cure well when the material is porous like wood.

AND NOW FINALLY?.


For wood handle scales to metal:
Recommended:
Gorilla Glue beat out every other adhesive in every test
Loctite E-120hp
K&G epoxy
Golf shafting epoxy by Golfsmith
Acraglass

Avoid:
Anaerobic curing adhesives
JB Weld

Full tang handles:
Acraglass which was designed almost exactly for this kind of application.

Avoid:
Gorilla Glue or any other polyurethane expanding type glue.

For metal to metal
Recommended:
Loctite Speedbonder 324
JB Weld
PC7

Avoid:
Any CA?s, ie superglues. These have no place in knife making anywhere except to fill flaws in handle material.

For metal to man made materials (ie, G10, micarta, etc)
Recommended:
Loctite 324 Speedbonder or any of the overall use adhesives.

For overall use:
Loctite E-120hp
K&G Epoxy
Golfsmith Golf shafting epoxy
Acraglass (Acraweld is different and was not tested. Acragel was tested and failed)"
__________________
Tracy Mickley

[tmickley]

Andrew, you are correct, that was a typo on gorilla glue in the bottom 'summary', I meant to say avoid gorilla glue or other expanding glues for hidden tang. Two reasons: the expanded foam doesn't have any strength, the other reason is you don't want your knife handle and guard pushing each other apart while it cures. Funny after so many views on that thread some one caught a big typo, i'll go back and edit that out.


As an update, I have not found any better adhesives lately than the Loctite 324/325/330 stuff for knife making. There are some minor differences between all three but basically they are close enough alike you won't go wrong using any of them. These are all anerobic so they will not cure well with porus wood. Gorrilla glue is still an insanely good and economical adhesive when used in the right conditions.

I have gotten more aggravated with how bad it stains my hands for days when you get it on you but it's a good reminder to always wear latex or vinyl gloves when handling these toxic cancer causing chemicals.

There is a new Loctite adhesive that just came out that looks to be better than anything mentioned so far, at least on paper and accordig to the Loctite rep. I've had two meetings with my Loctite industrial rep and he gave me some samples of a this new one and a couple of other glues that I'm going to test and I'll add the results to the glue wars thread.

I am still in the process of sourcing Loctite adhesives to sell on my supply web site. It is taking FOREVER to get anything done but the Loctite guy turned me over to a wholesaler that is working on setting up my account - at a glacial pace, but I should have something in a few weeks - maybe.

[EdStreet]

whats the new loctite model number? I use 324 almost exclusively and I have to say it's super awsome. Sometimes I wish it would take longer to set and I always wear gloves when working with it.

I have this shop hand soap that will remove anything on your hands. One of my clients is a bodyshop and that's what they use so I grabed some. It will eat the paint off a sink and all that good stuff. Not harsh either.

Ed

[NJStricker]

Since Gorilla Glue is so great on wood, I would think that by employing some hidden pins on a full tang, and using thin oak dowels for those pins, you could create an extremely strong handle. Have any of you guys tried this?

[Don Robinson]

It's really good to have David Broadwell posting on the forums. He can teach us all a lot.

Thanks for joining us, David.

I'll listen to anything you have to say.

[EdStreet]

in all fairness loctite 324 didn't receive alot of ratings as it should have. On the xls sheet it's blank for most of the groups.

Ed

[David Broadwell]

Thanks, Don. I'm as flattered as I can be! I am happy to share what I might know. I'm also happy to absorb what you guys know. It works both ways.

David

[DaveL]

Also, Loctite 330 "Depend" did not get a test. I think these Loctite Adhesives are the best and many makers use them. That says a lot...

[tmickley]

Originally Posted by Armory414

Since Gorilla Glue is so great on wood, I would think that by employing some hidden pins on a full tang, and using thin oak dowels for those pins, you could create an extremely strong handle. Have any of you guys tried this?

just make sure to prepare the metal surface properly and your wood will fail before the joint will...

[Kirby Bletcher]

David Broadwell, which of the system 3 epoxys are you using? I visited there web sight and found they have several different ones.
Thanks

[David Broadwell]

Kirby,

I use the T-88 adhesive. It's a bit thick, but will thin with some heat (not too much heat or you'll set it off prematurely). It flows about like room temperature honey, which means not really well. To get it inside a hidden tang knife handle I just stuff it down inside with my mixing stick and the knife tang.

The last time I bought any was from this company: http://woodturnerscatalog.com/ Go to adhesives. They were a little less expensive than the manufacturer.

David

[EdStreet]

does this mean there's another epoxy test in the works?

Ed

[tmickley]

Originally Posted by BlackNet

does this mean there's another epoxy test in the works?

Ed

quite probably... I started looking for my favorite piece of test steel the other day. I have some wood blocks all ready to go.

[canyonman]

I might also add... Acetone does not cut oils worth a ####. In stead of Acetone I would consider sticking with alchol maybe even cleaning the steel with warm soapy water and drying it first.

Larry

[EdStreet]

When I spoke with loctite they suggested I use alcohol. Also said be careful because some products like simple green leaves a residue. Now in the scuba industry some use simple green to o2 clean tanks which is a big nono and they will be very aggressive about telling you that simple green does not leave a residue but bottom line it does.

I did have a gunsmith tell me to use bisonite for full tang knives. Suppose to be pretty good and way better than the acra stuff.
http://www.championshooters.com/bedding.htm
http://www.actioncastings.us/My_Home...es/Page21.html

Another interesting thing is I was watching mythbusters last night and they showed some sword breaking myths and had a high speed camera footage. The footage was the sword getting hit with another sword and the harmonics were just incredible. Made me think of smaller knives. Mostly on how brittle things are with the epoxy's used and how that affects the structure as a whole.

Ed