a question for those that don't solder guards

Matthew Gregory said:
Over time (and that amount of time can be a LONG time, I'll admit) epoxies and most other similar materials will break down, whether it be through oxidation, UV, heat, etc.
Click to expand...

And you base this upon what? What data do you have on this or is it just an opinion...or speculation? Sorry to be so blunt but playing the devil's advocate here. You state this on what evidence. Terry caught a lot of unjustified nay saying on this. Unless someone has anything concrete concerning this then it really doesn't hold water...

Craig
 
Just to be clear, are you saying that there isn't evidence that epoxy breaks down under some or all of the conditions listed? I thought it was pretty well understood that epoxy does break down under UV exposure. Epoxy based paints break down over time due to UV exposure, it's called chalk out.

I can tell from first hand experience that at least some epoxies will release bond under exposure to heat.

Here's an interesting paper discussing the erosion effects of UV exposure combined with moisture (both things that knives see) on epoxy in carbon fiber laminates:

http://stuff.mit.edu/afs/athena/cou.../slides/J_Composite_Materials2002v36p2713.pdf

Matrix dominated properties are affected the most, with the transverse tensile strength decreasing by 29% after only 1000h of cyclic exposure to UV radiation and condensation.
Click to expand...

Yes, it's 1000 hours, but he did say "LONG time".
 
C L Wilkins said:
And you base this upon what? What data do you have on this or is it just an opinion...or speculation? Sorry to be so blunt but playing the devil's advocate here. You state this on what evidence. Terry caught a lot of unjustified nay saying on this. Unless someone has anything concrete concerning this then it really doesn't hold water...

Craig
Click to expand...

Hi Mr. Wilkins. The information I got came from a handful of material science engineers that are friends/acquaintances of mine. I'll ask them if they can provide me with appropriate documentation, but many of them stated it as though it was considered a given... again, I wish to state the point of this thread. I already know that the adhesives I have are in many cases stronger than the materials I'm using - what I'm concerned with is the EXTENDED lifecycle of the adhesive. 100 years from now, will my knife withstand the rigors of time?
Why is this important to me? I want my knife to be something the owners (both now and then) cherish. Sounds silly, but I shave every day with a straight razor that was made in 1892. It was made so that if it is taken care of it will continue to be usable - and appreciated!

Who is Terry, btw?
 
Fiberglass boats are made of epoxy resin soaked into glass fibers, so are Corvette bodies, some of the original Corvettes are over 50 years old now and still strong

-Page
 
RJ Martin said:
IMO, a beautiful, neat fillet of solver solder that is uniform and polished is one of the hallmarks of a well made knife
Click to expand...

Ditto that :thumbup:

I solder all of my mono steel knives that have a guard.

However .................. it sure is a pita when the solder goes somewhere it's not supposed to be. Specifically, on a Damascus Blade or a Blade you've worked 3 days finishing and etching to show beautiful Hamon.
That's where the JB comes in for me :)
In regards to failure, I eliminate any chance by adding a pin to all of my guards, soldered or JB'd.
By failure, I'm referring to movement, the guard loosening up from rough use and/or because of handle material shrinkage 10-20 yrs down the road.

The use of a pin brings up another issue if and when you're using a guard made from Damascus ............ that issue being, making a Damascus pin that will blend in so it's not sticking out like a sore thumb :grumpy:
I guess that's what we as knifemakers do though isn't it, overcome new challenges that arise as our skills and work improve :thumbup:

God I love making knives !!!!!!!!!

Thems my thoughts on that there subject Matt ;) :D


:cool:
 
Last edited:
sunshadow said:
Fiberglass boats are made of epoxy resin soaked into glass fibers, so are Corvette bodies, some of the original Corvettes are over 50 years old now and still strong

-Page
Click to expand...

In both of these cases there is something over the epoxy helping protect it from the elements. In neither case does the epoxy have to deal with expansion and contraction of dissimilar materials. And in both cases, the most prime examples are dry docked or garaged when not in use.

I don't think it's a fair comparison.
 
I'm surprised no one brought up galvanic corrosion issues in various methods. If the guard is of a dissimilar metal you can have problems with galvanic corrosion at the joint. Epoxy will prevent problems with galvanic corrosion, but there's always going to be a problem in that area around the perimeter of a soldered joint. Another problem is that low temperature soldered joints really aren't as strong as most people would like to think and may just be giving a false sense of security.

If we want to get theoretic and silly about it and say things like, “what if ?”,… The galvanic corrosion around the outside perimeter of the solder seam, instigated by the solder itself, could eat the blade clean off at that very spot. Or,... what happens if it corrodes clean through 100 years down the road and the blade falls off?

One method is not necessarily any better than the other, it’s how you use it, what you do with it,... and how good of a job you do at it.

Nothing is fool proof. Don’t abuse knives.
 
Last edited:
David Wesner said:
In regards to failure, I eliminate any chance by adding a pin to all of my guards, soldered or JB'd.
By failure, I'm referring to movement, the guard loosening up from rough use and/or because of handle material shrinkage 10-20 yrs down the road.

The use of a pin brings up another issue if and when you're using a guard made from Damascus ............ that issue being, making a Damascus pin that will blend in so it's not sticking out like a sore thumb :grumpy:
Click to expand...

Just an idea, make a pin behind the guard, pressing it in place (towards the blade) and let the handle material slip over the pin.
 
I like what Tai says. A prime example of a lasting work of steel art is an ancient katana. Or tachi. I was looking at a pic of a tachi from ca. 1250 yesterday, it's been repolished probably once every 100 years and is pristine still. Almost 800 years that blade has survived.
The Japanese, with their attention to detail and quality, still seem to view fittings as being secondary to the blade, indeed they just don't last as long and many old blades have been re-mounted many times or stored in shira-saya.
Many of those swords, the owner would have a heart attack if you even sneezed in the same room as one. The finish is so delicate, yet these blades only use a pin, no epoxy or solder to retain the grip or fittings. The word is care. (I know that is an extreme example, but don't leave your knife out in the sun for 1000 hours. Jeez.)
 
Also, it dawned on me that maybe what this thread means is merely that the integral is the ultimate knife.
 
Maybe the Corvette/boat example holds a little water. I don't think the average knife gets the temp swings like a corvette hood, and some of us have seen the old beater fiberglass boat that's been sitting for years in the weather, float just fine.

Does the epoxy beneath a well fitted guard get any appreciable uv or oxidation exposure. Depending on the epoxy, custom 'micarta' may have a tougher time sticking around for a thousand years.

Take care, Craig
 
So many of the things we say and do in our quest for the “ideal knife”, (whatever than means), seems to be dictated by the wash and wear/dishwasher safe society we live in,… and may also be self defeating in that it often just perpetuates and invites “knife abuse”.
 
Salem Straub said:
don't leave your knife out in the sun for 1000 hours.
Click to expand...

Yep!

And,… don’t leave it sitting in a jar of acid overnight, or beat it over an anvil with a 2-1/2 pound cross peen. :)

It's just common sense.
 
Last edited:
actually, drilling a blade for a pin to secure the guard concerns me much more than any other issue brought up so far. The two places I have always seen people's knives break in use are within an inch of the end, and right at the guard. where the stresses typically concentrate at the transition, drilling a hole there and inserting a pin seems to me to be inviting failure.

-Page
 
While it is interesting to speculate in a general way about these matters, insisting on specific data is really a bit unrealistic.

Let's remember we are talking about epoxies here, and mostly those are based on mixing two components. As much as we may take pride in our work, I daresay that any two mixings (even from a single individual doing multiple jobs) is likely to result in some differences in the final formulation, however subtle. The resulting epoxy is therefore going to vary in quality and longevity based on the proportions of resin to hardener (leaving aside any contaminents), the temporature at which it was mixed and set, the age of the chemical components, and so on.

But let us once again return to the original question. The basis for this thread was to find out if anyone had observed a failure... not whether failures were theoretically possible. It's a fairly simple and straightforward question that becomes convoluted when turned into a theoretical discussion.

That said, I would say any answers to the real question should be taken with a grain of salt, for exactly the reasons mentioned above. If someone did notice a failure (or pattern of failures), does it mean they have evidence that epoxy doesn't last... or evidence that they don't know how to mix and use epoxies? ;)

- Greg
 
tryppyr said:
But let us once again return to the original question. The basis for this thread was to find out if anyone had observed a failure... not whether failures were theoretically possible. It's a fairly simple and straightforward question that becomes convoluted when turned into a theoretical discussion.

- Greg
Click to expand...



If failure can occur, it will occur…. "Anything that can go wrong, will go wrong", Murphy’s law! It's just a matter of time... unless the knife is vacuumed sealed in a time capsule and never opened and never used.

"It is found that anything that can go wrong at sea generally does go wrong sooner or later, so it is not to be wondered that owners prefer the safe to the scientific.... Sufficient stress can hardly be laid on the advantages of simplicity. The human factor cannot be safely neglected in planning machinery. If attention is to be obtained, the engine must be such that the engineer will be disposed to attend to it."

We don't have to witness failure to know that it occurs...
 
Last edited:
Just how much UV can get to the epoxy through the hairline joint at the guard?

Compare with a boat sitting out in the sun.
 
The epoxy in the boat isn't generally getting exposed to UV, it's generally painted, and often several times over it's life span.
 
I thought we were talking about the epoxy that is exposed to UV, not the epoxy that's behind the guard...

The epoxy in the joint is where we're talking about failure, and since that is exposed (unless you have four shoulders) it gets UV exposure. A boat depends on a large surface area of epoxy that's largely or entirely covered, the joint in question depends on a very small bit of epoxy (probably thinner than the manufacturer's minimums) and that bit is exposed if there is a joint. Wherever it's exposed to UV it has the possibility to break down.
 
You must log in or register to reply here.
Back
Top