Questions on soldering/brazing carbide strips

So I had bought a file guide when I first got into this knife making and here a while back I went to use and tightened it and snap! Of course I was told by the maker I must have over-tightened it. Ah, Nope, wasn't tight enough to stop movement yet.

So disillusioned with hardened file guides I began searching. I soon realized the guide didn't have to be hardened at all. All I needed was some carbide strips for the belt to run against!! So I have made a couple of file guides similar to this.

The first one I made I used JB Weld and it held until one night I finished using it, took it off the knife and lightly tossed it up on the work bench!! The impact caused the JB Weld to fail. The epoxy had been fairly thin.

So I thought about doing something like this one in the photo I got off the net. Grooves for the epoxy but that still doesn't allow for the fact the epoxy will not perpetrate the carbide strips!

So After doing some reading about the subject I found out that carbide can be soldered with silver solder to steel. It can also be brazed to steel.

So the million dollar question has anyone tried soldering or brazing carbide to steel and which is the easiest to do! From my reading I think the soldering w/silver solder might be the best!

Anyone got any advice on the subject?????

Cliff, I have silver soldered hundreds if not more Carbide tips on steel shanks and carbide shanks for boring bars. I recommend that over brazing. You can buy silversolder in shim stock like configuration. It is stronger than brazing in that type of application for the type of project you have going. Much cleaner looking too. I have never had a tip pop off a bar.

Here's the "recipe" I learned many years ago from an older machinist:

You clean the steel absolutely sanitary...carbide too. Acetone and 600 grit paper if you can.... finish with soap and water wash and dry well. Take the silver solder sheet cut to the pocket size and lightly sand to remove oxidation (oxidation on ANYTHING when silver soldering is your enemy!) clean in soap and water when done. Now "assemble" the carbide and steel....flux the steel pocket, both sides of the silver solder snippet and the bottom of the carbide piece. Don't go crazy with the flux! Anywhere you put flux the SS will run to when it starts to flow. So wipe any extra flux off. I prefer the white flux (they make a black also...i think higher temp but can't remember)

If you take an old chunk of steel and drill a hole about 3/16 or 1/4 for about 2 foot of rod the same diameter you can make a nice little soldering aid. Bend a couple of inches of the rod 90 degrees (sharpen like a pencil first) this allows you to put some pressure on the carbide while heating. set the block on your bench and the tip of the rod in the center of your carbide insert. Ideally the steel part is in the vise. The flux with boil and if you don't have something pinning the carbide to the pocket it will boil out leaving you to reclean and remove flux and start over....

so before soldering your nice little pieces, (called silver brazing also....don't let the word "solder" fool ya...this stuff is immensley strong!) practice on two pieces of steel about the same size. You will have to play with torch settings but usually you don't need a ton of oxy....about a one inch blue flame that does not sound like a cutting torch will suffice...lol.

"tickle" the two pieces slowly bringing up the heat. The flux will "boil" first and after all the moisture is gone it will turn clear and stop boiling...then you keep heating till you see the silver solder start to run...(your two pieces will be glowing a bit...it's ok) when it is nice and shiny and liquid take the heat off. Let it cool leaving the weighted rod on the parts till cool to the touch. Until that solder hardens (which is very quick) the rod is doing the work of holding it all together. do not ever quench when silver brazing....specially with carbide on there.

The white flux cleans with hot water and detergent it will dry clear...if you blackened it you were heating it too quick. the hardened solder should be silver with a hint of bronze to it. If you see gold you got it too hot. For what you are doing it shouldn't really matter because your not really working that joint....so not need to redo if you over heated a bit.

have fun.

Hope this helps....

quick question: the carbide strips that are available- do they need to be surfaced or do they come precision ground? I see strips that come in six inch lengths. How do you cut them?

https://www.mcmaster.com/#silver-solder/=16ky3yt

You can also use the roll type of Silver solder if you don't want to use the sheet stock. Just feed the solder into one corner (after flux is done boiling)
and when you see it on the other side you're done. I had forgotten how expensive the flat stuff is ($56)...and that's probably a lifetime supply for most of us...

I have three different carbide file guides..... one with the carbide "glued" in place, and the other two are dovetailed into the steel. The one thing I have learn is that no matter what method used to hold the carbide in place, it's best to surface the carbide once it's in place. The reason being that there are few things more frustrating (if using it for shoulders on hidden tangs) then to finish out the shoulders, remove the guide, then find that the shoulders are uneven and a guard will not fit cleanly..... and after a day or two of looking for the cause, it finally dawns on you to look at the file guide....and you find that the carbide isn't level and square to everything else. :biggrin:

John Wilson said:

quick question: the carbide strips that are available- do they need to be surfaced or do they come precision ground? I see strips that come in six inch lengths. How do you cut them?

Click to expand...

I have been wondering the same thing. Hopefully someone can answer this. Is it like glass? Scratch it and hit it with a hammer?

about the only thing that'll cut clean is a diamond wheel. You can slog your way through with a green wheel and still have to clean ends later with diamond. I do not have any diamond cutoff wheels...I'd be willing to bet a small tile saw wheel (they're diamond impreg also) would do just fine. You can saw carbide wet if your coolant is steady generous flow...otherwise dry and don't "push" it. I have diamond wheels for surface grinding that work well for flat grinding. Also, use a mask to cut it. I ground it with no mask for years at the manly man shop I worked at. now if I even touch up a boring bar on a diamond wheel I will just about vomit without a mask. I don't think carbide dust is very good for you....

No it's not like glass...but you might get it to snap pinching in a vise an tapping with a hammer on a thin piece like that.

No it's not like glass...but you might get it to snap pinching in a vise an tapping with a hammer on a thin piece like that.
That comment was a poor attempt at having a sense of humor while at work and not wanting to type to much. Thank you for helping out with the question of cutting it. I figured it would take some kind of diamond tool to cut it.

I figured Ty...then got to thinking about snapping it....It might just work.

Oh, I'm great at chucking things up in a vise and snapping it. (hold my beer while I straighten out this warped blade)


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thanks for the replies. i'm using a file guide i made and hardened but I was thinking of using carbide on the next one.


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Thanks everyone, sorry I haven't had time to check on this thread today. Me and the Misses have had two Grand-babies living with us since Wed., morning, one is almost 2 and the other is 4 going on 40! :lol:
Both parents had to go out of town. Mama on business and Daddy had a National Guard meeting. Last night after having them all day, and supper and bathes and getting them to bed!
I sit down in my chair and looked over at the wife. Honey, I says, I don't remember it being this hard when we had our kids. She looked at me and said, we were a lot younger then!! Oh, yeah I hadn't thought of it that way!!! :what!: :biggrin: Next time I answer the phone and I hear, hey can you do me a big favor....................! Oh well having the time with them is priceless, even if I do get tired easier anymore!



I have never tried the process, (soldering carbide to steel) so this will be a learn as you go process! I know on today's saw blades the carbide tips appear to be brazed. However,I would be willing to bet that is all done by machine at one shot.

My research pretty much had me convinced to try the SS. If I hadn't gotten any feedback that was going to be my approach!! So once again thanks for the info. Now I just got to wait till the Grand-babies go home tomorrow night! In other words it will probably be the weekend before I dive into this one!:57:

John, when I had the carbide strips JB welded to the first one I made they were fantastic. You could hit the belt and just barely touch the carbide and then work to the point and when done the carbide didn't even look like it was touched. I think it is the way to go because you don't have to work about over tightening and having the hardened file guide snap. When I tighten down a file guide I don't want it moving till I am ready for it too move!