Soldering Problems

I'm not judging who's technique is better. I'm taking notes from everybody! I'll probably use a bit of all these methods in time depending on the circumstances. I'll try a few ways and see what works for me. But even between techniques there is overlap in certain areas and that is a good place to start. I think I was on the right track initially but just didn't get the heat high enough or fast enough. I have another guard to solder coming up soon so I want to get as much information as well as tips and tricks as I can collect. You guys are the best!

Then, I have another blade (80CrV2) which will be cold blued and it will get a 416 stainless guard. should the tang area under the guard joint be masked so there is clean bright steel to which the solder can adhere or will the solder work over the bluing? Or is this a better job for epoxy?

gg,

What is the consistency of the heat sink mud? Is it stiff like wallboard spackle or more runny like toothpaste? Will the HS mud put in front of the guard stay there if turned upside down without the Dixie cup? Does it change consistency when the heat is applied? That is to say, does it get baked on and crusty or can it be easily wiped away after the soldering is complete? Can you post a picture of what your propane flame looks like when it is at the intensity you feel is best for your technique?
 
If the joints are smooth and clean, it is hard to make a guard and tang too tight a fit for solder not to flow. Two plates of metal can be soldered that are placed flat together and clamped.
That said, about 5-10 thousandths of an inch is a good spacing for the solder to flow through and made a good seal.
 
Ok, great. What about these combinations? Is the low temp silver-bearing solder good for all these joints?

Carbon steel blades/Brass guards
Carbon steel blades/Copper guards
Carbon steel blades/Stainless guards
Carbon steel blades/Nickel Silver guards
Carbon steel blades/Mild steel guards
Carbon steel blades/Wrought iron guards
Stainless blade steels/Brass guards
Stainless blade steels/Copper guards
Stainless blade steels/Stainless guards
Stainless blade steels/Nickel Silver guards
Stainless blade steels/Mild steel guards
Stainless blade steels/Wrought iron guards
 
Ok here is a great way to solder any type of hidden tang guard.

First the guard needs to fit tight press fit it in any way that you are accustomed to doing it.

Take the guard off and clean up everything no oil buffing compound etc. if you like mask the blade off to just behind where the guard fits the tang. (you don't want the next step to show at the front of the guard.) then bead blast the tang.

apply flux to both tang and inside the guard slot. press the guard back onto the tang.

clap the tang in a vise point up. heat the tang of the knife using a propane or map gas or an acetylene torch. keep the flame under the guard. when the flux starts to bubble up between the guard and the tang periodically remove the flame and touch the end of your solder to the underside joint of tang and guard. if it melts great if it don't apply more heat and recheck in thirty or so seconds.

if you are doing a Damascus blade you can paint the front of the guard and the blade with yellow ochre or even a magic marker to stop the flux/solder from flowing up the blade and ruining the blade.

when the solder flows run some around the bottom of the guard and the reapply heat. at this point you should see a small tight line of solder appear on the top side of the guard around the joint. if not apply a little more heat if you still don't se this small line of solder take a pointed piece of steel or brass rod dip it in some flux and carefully pull it around the joint. if you still don't have solder then while it is still hot tap the guard off re-clean everything after it cools and try again. with a little practice the solder joint is so nice and clean that virtually no clean up is needed.

I guarantee you that this will work. at first expect to get some extra solder at the front of the guard but it can be done so that the solder barely shows.
 
Cleanliness is next to Godliness when soldering. Most people clean the blade and guard, but many do not clean the solder itself. The oxidation on the solder will make the solder just ball up and prevent the flow of the solder. I take a piece of 600 grit paper and clean the solder when using tin based solder (Tix and Stay-bright). I will then clean the solder in denatured alcohol. A dip in a dilute baking soda solution after soldering will neutralize any of the acid left over from the flux.
 
i4Marc said:
What is the consistency of the heat sink mud? Is it stiff like wallboard spackle or more runny like toothpaste? Will the HS mud put in front of the guard stay there if turned upside down without the Dixie cup? Does it change consistency when the heat is applied? That is to say, does it get baked on and crusty or can it be easily wiped away after the soldering is complete? Can you post a picture of what your propane flame looks like when it is at the intensity you feel is best for your technique?
Click to expand...

The heat sink is much like vinyl spackle once you knead it a bit. It stays in place very well, but I doubt it would stay in place without the cup when it gets hot.

I don't think I tried that though. The heat sink stops the heat from coloring and over tempering the blade, which seems to be a concern only in my mind.

The mud stays good. After I'm done I put it back into the container. If you neutralize and wash your blade like you should, the water soluble mud is the easiest thing to clean up.

I use an O/A (not propane) welding tip with an .043 orifice (Smith MW203). I open the C2H2 until I have little smoke, then use a carburizing flame with about 1.5" cone. I might tone it down a bit to get a fairly quiet flame, but it heats things quickly.

I also found it more difficult to solder "upside down", where you can't see where your solder is touching or melting, and "practicing soldering" on finished blades was beyond me.

I really don't like flying in the face of conventional wisdom, but it solved my biggest hangups.

Maybe it will work for you, but you have to consider I'm only one bladesmith.

I suggest you try the accepted way first, especially if you are able to clean up foibles. I think it takes more practice, so try it several times.
 
I believe that you are holding the torch flame too close to the tang. Move it back and take another 15 seconds...the solder will melt all of a sudden and its done if there are no bubbles or tiny holes I have only used this technique about a dozen times but it has worked well for me. Larry
 
You must log in or register to reply here.
Back
Top