Two part epoxy vs solder

[cochise60]

For those with a lot more experience in knife making. Which is better to secure metal parts to the blade tang - two part epoxy like Devon or solder? The individual that got me into knife making uses two part epoxy - said he could never get the solder to come out right. My opinion is that solder is stronger and since it melts at a higher temperature is less likely to fall apart if the knife is put into something like boiling water.

[skipknives]

Just like painting a landscape,,,there are many ways to do it and they are all up to the artest,, and none are wrong,,that is why I'll start my answer with "if i were going to do it i would......"

if the guard slides onto the tang,,I would soder it,,,
if the bolsters are sandwiched to the sides of the tang/blade,,i would drill 1/8" inch holes in the blade (where the bolsters will be) and i would drill at least 3 holes a 1/4" inset from the edges,,then after heat treat,, drill the bolster steel to match,,and then pean the pins till the little bit that is sticking out of each side is almost twice the dimeter they started,,
in other words,,,swat the dog-snot out of them,,,then use the belt sander to trim and shape,,,

i would NOT use epoxy to hold bolsters to the side of a blade,,save that for the handle slabs,,,

now mind you there are 20 other ways to get the same job done,,,
Skip

[AcridSaint]

Of course, like Skip says, there's more than one way to skin a cat. Everyone here has their own way, some will be better than others for some situation or another. The way I like guards to be fitted may not work for kit knives, but I like the slot of the guard to slide over the tang and butt against shoulders on the blade. I was taught this by Alan Folts, you put a small shoulder on either side with a belt (or mill it if you want to get fancy, you can even go all the way around), then when you slide the guard up, it stops in place. At this point, you can take your handle material, flatten the edge on a platen, disc or mill, butt it against your guard, secure it and drill any pin holes you might need. If you can clamp lengthwise, from the back of the handle material, this will give you a nice tight joint.

Now when you put it together it doesn't really matter which method you use to secure the guard, because it's held tight between your handle material and your blade. You can do this with a stub tang in pretty much the same way, some folks like to pin their handle on a stub tang and some don't. The pin hole can be ever so slightly offset, so that the pin pulls everything together. On a stick tang, you can tighten everything up from the pommel.

If you have a large enough guard, you can also pin it in place, which will be stronger than glue or solder.

[ranger1]

I use both.Not as a means to secure the guard but to prevent moisture from getting between the guard and blade.I do not feel that epoxy or solder alone is sufficiant to secure a guard.You also need either a pin or pessure from the handle.Also a good tight fit.

[Ray Rogers]

I agree with all of the above. There have been many discussions on this subject in the past and you may want to use the Search to look them up.

To me, the important elements of the answer to your question are as follows:

Never use epoxy by itself to secure metal or wood to another piece of metal on a knife. Our Glue Wars thread taught us that under the right circumstances this can be made to work surprisingly well but the opportunity for failure is very high.

Devcon and most other similar epoxies will break down under hot water or sunlight over time. The main purpose for using epoxy on a knife is to seal out moisture rather than to provide structural strength. That said, anyone who puts a fine handmade knife in a dishwasher deserves what they get.

Solder is definitely stronger and requires significantly more skill to use properly than epoxy. If you can learn to use it, more power to you. However, JB Weld is used in place of solder by many knife makers including me. If you have a good metal to metal fit then JB Weld can do an acceptable job of filling the gap, sealing out moisture, and adding a small amount of structural strength. It is easy to use, does not leave flux behind which may cause damage to the blade over time, and cannot over heat the blade when you apply it, all of which is possible with solder. It's even a good color match for most metals...

[cochise60]

Thanks to all of you for your very thoughtful answers. I had never even considered JB Weld until I read about it last night. Oh - so much to learn - but as someone said this knife making business can become addictive.

[Ray Rogers]

One last thing if it wasn't already made clear: no epoxy, not even JB Weld should be relied on to secure bolsters to a blade. JB Weld alone is OK on a guard for a stick tang which passes through a hole in the guard but other types of guards and all bolsters should be pinned or held with screws. Even solder cannot hold these pieces by itself in all cases so don't think that JB Weld will do it.

Even though it is true that either solder or really good epoxies and proper metal preparation can have considerable strength it is best to just think of them as moisture sealers when used on a knife. If you think of it that way, you'll know you have to use pins, screws, rivets or something structural to hold the knife together and your knives will avoid that particular embarrassing failure ...

[DaveL]

You can forget Devcon for anything

[cochise60]

DaveL,

Why don't you like DEVON and what do you use in its place?

[cochise60]

Devon = Devcon

[DaveL]

If you look up the adhesive tests done here, followed by many, you will see Devcon failed the most. It has not been good for me anytime. I use Loctite 330 most of the time but the top brands in the test were not Devcon for sure.

[Ray Rogers]

DaveL is correct that Devcon failed badly in the Glue Wars. But, to me at least, that's not the same as saying isn't isn't good for anything at all. I still use Devcon 2-Ton inside stub tang handles and have for over 10 years with never a failure. The reason it works for me is that I follow the rules mentioned above: it isn't used in a structural context, and it's inside a stabilized wood handle where it is not exposed to water, sunlight, or high heat. I use it because it's easy to mix, doesn't shrink noticeably, flows well so I can get it inside the handle, and has sufficient pot life for the way I work.

There is no question in my mind that there are many epoxies that are far better than Devcon 2-Ton and, in fact, I use some of them when called for. But, as long as you match the working characteristics of any epoxy to the way you use it, most any glue is good for something....

[Ed Caffrey]

Since we're talking about "glues", I'll chime in with my 2 cents worth.

Nearly all of the two-part epoxies commercially available today have two major drawbacks.

1. The are produced chemically, so that they begin to break down within 4-5 years of the application. This is done intentionally by the engineers of the companies who produce most expoxies. Why? Because they want you to have to purchase more of their product. How long would they stay in business if their epoxy lasted forever?

2. Shelf Life: Again, we're speaking of the majority of commercially available 2-part epoxies, which have a shelf life on only 4-6 months. Once again, they are chemically engineered that way, so that you will be forced to buy more.

There are only two varieties of 2-part adhesives that I am aware of, that go beyond these two drawbacks. One is Acra-Glass from Brownell's. This is the product I use, and the one that I know the most about. It has a shelf life of 10 years, and a guaranteed hold life of 50 years, and when cured is TOTALLY waterproof. The other is an epoxy that for the life of me I cannot remember the name of right now, but I can tell you that it was designed for, and used to assemble golf clubs. It has a 2 year shelf life, and a guaranteed hold life of 10 years, and it is also totally waterproof.

After doing some extensive testing a number of years ago, I am forced to agree that I would not recommend Devcon epoxy for anything. Even their epoxy that claims to be waterproof is not. "Slightly water resistant" would be more accurate.

I learned this fact by putting scrap scales on two different blades. One with the regular 5-Minute devcon, and another with their "2-ton". After curing and finishing, I dropped both into an old coffee can that was about 1/2 full of tap water. The next morning I was able to slide/pull the scales off both because the epoxy had become waterlogged and gummy. (these were micarta scales)

The reason I took such a keen interest in how adhesives preform is because there is nothing worst for a knifemaker than to have a customer show up 5 years later and complain that the handle on the knife you sold him/her is coming off!

As for the guard being epoxied or soldered, my view is this. If you have to use anything on a guard to hold it in place, then your guard fit needs work. Whether its JB weld, epoxy, or solder, its only purpose should be as a water barrier. For bolsters, I believe that pinning is the only logical, permanent way to attach them. How you water seal bolsters depends a great deal on the specific knife.

[AcridSaint]

Originally Posted by Ray Rogers

DaveL is correct that Devcon failed badly in the Glue Wars. But, to me at least, that's not the same as saying isn't isn't good for anything at all. I still use Devcon 2-Ton inside stub tang handles and have for over 10 years with never a failure. The reason it works for me is that I follow the rules mentioned above: it isn't used in a structural context, and it's inside a stabilized wood handle where it is not exposed to water, sunlight, or high heat. I use it because it's easy to mix, doesn't shrink noticeably, flows well so I can get it inside the handle, and has sufficient pot life for the way I work.

There is no question in my mind that there are many epoxies that are far better than Devcon 2-Ton and, in fact, I use some of them when called for. But, as long as you match the working characteristics of any epoxy to the way you use it, most any glue is good for something....

I agree with Ray, there is usually a time and place for a given glue. There is a stub tang santoku knife in my kitchen right now filled with devcon. The handle is not stabilized and it still manages to hold up to my wife's ...... treatment. Not saying it's better than many others, but it does just fine when I use it.

[jdm61]

I make hidden tang knives and use JB Weld. As for rhe epoxy issue, true marine epoxy like West System would probably work also.