Soldering

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I have just gotten into knife making and I am doing Ok. The area that I am having an issue with is soldering the guard to the blade. I first pen it and then solder, but I am really sloppy and have to do a great deal of clean up. Is this normal, I am just using a propane tourch, but am thinking of a fine line soldering tourch ( like a jewery tourch) would that help becuse I think it would focus the heat better. I am using silver solder, I think it is called stay bright, I purchase it from Janz, should I use another solder, is it something you just pick-up after a time, whatever you can provide may help.
 
Here is how it was explained to me. This always work but practice makes it better.

Rules
1. Clean
2. Clean
3. Clean
4. Parts must have a good mechanical fit (minimal gaps)
5. Use the correct flux for the solder and the metal involved
6. Heat the most massive and let the heat flow to the less massive part
7. Apply solder to the side of the work piece opposite the heat. The solder will wick through the cracks toward the heat source. The flame never touches the solder.
8. Apply only enough solder to fill the cracks

This being said, try not to overheat. If you can't get the heat on the side opposite the solder, remove the flame from the metal before toughing the solder to the metal. The heat from the metal should melt the solder, not the flame! Wrap a wet rag around parts you don't want to over heat. They will not get above 212°F as long as there is water left on the surface. The propane torch should work fine, just remember, the tip of the inner blue cone is the hottest point of the flame and the part of the flame you usually want in contact with the work piece.

Hope this helps

Jim Arbuckle
ABS JS.
 
I too am struggling w/ soldering. I've done research and practiced a bunch w/ sporadic good results. Is the method you described similar to brazing? Just lower melting point alloy?
 
For slipjoints...roughly size the bolster to the liner making sure that the edge toward scale is square and straight, apply flux to all pcs to be soldered, pretin all pcs, insert pins thru both liner and bolster to line up pcs, lightly clamp with spring clamps, apply heat from a propane torch upon the bolster, clean excess solder with solder brush while still liquid, set aside to cool.....complete. Do not get stingy with the solder. For a roughly 3/4" sq pc, I use about 3/4" long pc of solder about 1/16" diameter. After cool, remove pin...it will easily come out normally. If a little tight, use small hammer to drive pin thru holes ...but do not bend liner. Probably easier shown than explained...but.....
 
Sometimes the very tiny direct cocentrated heat of oxy/acyetlene is a help however
with what has already been said-clean! In straight blades I usually make stick tangs.
When the guard is clamped up where it is sitting flat on the bottom of the ricasso and
you start heating it (from Bob Loveless book) wash it out with muriatic acid before applying the flux then flux and reheat. Usually only a Q-tip to swipe off the solder on either side of the blade after that, very little clean up.
Ken
 
The joint must be clean and tight-first and foremost.
I use Stay Clean flux.
All areas that the solder touches should be freshly cleaned metal.
Heat only until the solder flows. Solder will flow toward heat. Use only enough solder to make the joint-solder should not be used to fill voids.
A propane torch should work just fine, but do not over heat.
Stay Brite solder is not really silver solder. It is a silver-bearing solder. The low silver content allows it to flow and stick to stainless steel. Real silver solder requires much more heat.
Solder will not flow past a pencil line, BTW.
 
Last edited:
sulsaMatt said:
I too am struggling w/ soldering. I've done research and practiced a bunch w/ sporadic good results. Is the method you described similar to brazing? Just lower melting point alloy?
Click to expand...

Yup, doesn't much which one you are using (under 800°F is soldering, above is brazing) Like I said, the flux used must be correct for the metal being soldered and for the solder. Certain stainless steels are harder to get clean than others, some require fluoride based fluxes which are NOT TO BE BREATHED! The acid swab mentioned in one of the posts usually cleans off any surface oxides and eliminates exotic fluxes. Just remember to clean immediately before soldering. Just a note don't put flux where you don't want solder. I normally use a thin piece of piano wire to apply flux to the joint of the guard and the blade and a boar bristle brush to wipe of excess solder. Coat areas you don't want the flux from pitting with a light coat of oil or cover with aluminum foil.

Hope this helps.

Jim Arbuckle
ABS JS
 
stay bright/stay clean has a liquid flux which is also a cleaner . I use an eye dropper to apply it . Another little trick , dip the solder in the flux , it will wash any corrosion that may be on the solder . Otherwise , as far as heat and clean , all the above said is very important .
 
Bill,

I haven't heard of the pencil resist... Can't wait to try that one and see how it works! Thanks for the tip!

Rick
 
The pencil resist works fantastically. I use it when tinning the liners when making slipjoints. You can heat up the solder and move it around to tin the whole area under the bolster and it won't go past the pencil at all.
 
The gap for proper capillary action is .003" .Take the time to fit things carefully. Always differenciate between solder [soft solder] and braze[ hard solder] Soft solder such as the 95Sn5Ag melts about 400 F and can be used on blades without damaging HT.
Torch flame - the outer cone is oxidizing and the inner cone is reducing .Tip of the inner cone is the hottest.
 
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