Working a Solder Joint

TK Steingass

TK Steingass

Troglodyte Knifemaker
Joined
Oct 16, 2010
Messages
5,779
Sometimes I get a solder joint that just won't come out looking nice. I use Stay Bright. Is there a dremel type attatchment out there that you fellas use to machine the solder joint? I would appreciate any other suggestions too.

In Loveless' book he talks about using muriatic acid (MA). Does plain old out of the hardware store MA work?

Is there a way to minimize getting solder on the rest of the guard in order to have less cleanup afterwards?
 
You can use a brass brush in a Dremel to smooth the solder.
 
It also helps to keep the joint as tight as you can before soldering, on a side note graphite and ocher will block solder flow to keep the excess solder from sticking where it shouldnt. I use a pencil and draw a line where the solder shouldnt be.

I also use a carbide scribe to clean up the solder lines in the joints, I have a piece of D2 scrap that I hardened and made a small chisel out of to get any stray solder off with.
Hope any of that helped.
Rusty
Oh and take your time, you dont want to scratch up the blade or guard too bad when your cleaning it up.
 
I use a 1/8"nickel silver rod, sharpened at a 45 deg. angle to scrap off the extra solder.

I tried the muriatic acid trick and didn't like the fumes.

Use the least amount of flux as you can and try to wet just the joint. Wherever the flux is the solder will follow.

Take care

Charles
 
I cut very small 1/8" long pieces of solder and place them on the joint between the blade and the guard, two per side (about 1" wide) and one per end. I very carefully melt and use a brass rod pointed at one end and flat on the other to spread the solder evenly across the joint. This eliminates the biggest mess and that is excess solder.
 
I tried using 45% silver solder, having hard time learning, is this not the right type of solider, my welding retailer said it should work
 
For soldering guards, you want "Silver Bearing soft Solder". Tix, Stay-Brite and Eutectic-137 are all good choices. Use the flux that comes with the solder. These solders melt around 400-450F.
Utican - The 45% silver solder you got is for silver brazing. It is a hard solder that melts at around 1100F. It is not what you want for knife work.

Take a piece of 1/8" brass or nickel rod and make a tiny chisel.Stick it in a piece of dowel to make using it easier. Use this to cut/scrape away any excess solder. The soft brass/nickel will not gouge the guard or blade like a hard scribe would, but will cut the soft solder and leave a shiny cut. Re-sharpen as needed.

The best way to avoid having the solder go where you don't want it is to not use too much solder or too much heat. The amount of solder needed to seal the joint on a guard ( assuming the joint is properly snug) is a very tiny piece. A piece the size of a grain of rice is more than twice what you need.
 
I make it a press fit with no slop. Then rub the face of the guard and sides of the blade with soap stone, clean the soap stone up with a file so you have a soft area that will coat the front of the joint.
Then Coat the outside of the joint with Duro no - run supper glue to seal the flux inside of the joint. let it dry overnight and silver solder, where the flux has not been the solder will not stick - usually.
When some does stick outside of the joint it easily comes off with a hardened brass chisel that is very sharp and just chipps it away.
 
You can use a soft lead pencil to simply mark where you don't want the solder to go.
You will ruin your heat treating using 45% silver solder. As stated, the 4-6% silver-bearing (containing) solder is all that is needed for guards. Plain lead solder will work on ferrous metals, but not stainless. All solder joints should be clean, bright metal. I use Stay Clean liquid flux for all my soft soldering.
 
Ty guys,Hehe, thats why I practiced on brass flat and tried attaching a nut to it, it worked but it got red hot before it worked, is it stronger than 5% silver solder?
 
Yes, hard solder is a brazing compound. Soft solder is not structural, only a sealant.
 
So actually I'm doing ok then, cause I'm making brass pommels by soldering a nut to a piece of brass . I make stick through tang that I make just long enough to make It through the handle then finish it of by threading the brass piece with the nut braised on. Will silver braising be strong enough for this?
 
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