Soldering Guards

ONeill said:
thanks Sam , I found that squirt bottle today at the art supply store , I have been using an eye dropper but it was still to much flux . Too cool .
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Excellent, glad you found them. I have been using them for a couple of years now and they work well for me. I hope you have the same success with them.


Bill DeShivs said:
Put your flux on with a brush or Q-tip.
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I have tried these and had better success with the syringe-type squirt bottle.

Sam :thumbup:
 
What does it mean when the solder sort of balls up on the surface rather than flowing? Does it need more heat? More, less flux? Im slowly trying things and I can get the solder to fill in the cracks but, it's not turning out very pretty. Not the nice seam that it should be.
 
If you touch the solder to the joint, after taking the flame away, and it melts, your temp is fine. If you are melting solder with the flame, chances are your work piece is too cold.

If the solder melts touching the joint but doesn't flow, chances are the joint isn't cleaned enough or fluxed properly. It can also mean that you over heated and oxidation formed on one of the pieces, at that point no amount of heat or flux will fix it, you need to abrade it clean and start over.

I just soldered a guard today I wish I had thought to make a video as it came out perfect for once. Just a nice thin solder line on the bottom and you can just see a hint of silver from the top where there is a slight gap in the guard fit, but no bleed through.
 
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Bill DeShivs said:
Then, you are using too much flux.
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Hello Bill , are you brushing the flux on the blade where the guard will be placed and maybe the inside of the guard before assembly and then solder ? Kind of like we use to do with paste flux .

Like Sam , I clean and then assemble and need to flow a small amount of liquid flux into the joint before soldering .
 
ONeill said:
Hello Bill , are you brushing the flux on the blade where the guard will be placed and maybe the inside of the guard before assembly and then solder ? Kind of like we use to do with paste flux .

Like Sam , I clean and then assemble and need to flow a small amount of liquid flux into the joint before soldering .
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I'm using a paste flux and an artist paint brush to flux. I clean the parts and assemble them, then paint the joint with a bit of flux like I was painting a fillet on the corner. I don't go into the joint before assembly, because the same capillary action that draws in the solder, draws in the flux when you heat it up. This (and a good tight fit) is what has prevented bleed through for me. When I was fluxing every surface prior to assembly, I would inevitably wick solder up through the joint and on to the blade.
 
I use liquid flux.
I generally use a brass rod to apply flux to the joint. I just stick it in the bottle and onto the joint.
 
colu41 said:
Well, I finally ordered some Stay Brite Silver Bearing solder, and Stay Clean Liquid flux. Wish me luck.
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Many many moons ago I learned to solder with lead solder and a big copper iron heated in the coal furnace in my father's shop. A few moons after that but still many moons ago I learned silver and gold smithing and soldered that with a plumbers acetylene torch and a small tip. Then I made silver and gold jewelry on my own and used a propane torch. Now I arrive at knife making and discover Stay Brite Solder and soldering a guard is so easy easy compared to to things in the past. Stay Clean Flux is like a miracle and the solder is far stronger than I would expect at that low melting temp. I removed a guard last week because I didn't like it and I was very surprised at how hard it was to break it free from the blade.
 
mknife said:
Personally,
I care too much to the integrity of my hands.
I would never use a knife that does not have a guard bound to the blade with pin. In my opinion the only brazing is not enough, the real strength is made by 2-3 mm steel pin that runs through guard and blade.

These are my pics, I use stay brite silver solder and Black & Decker HG1300 Dual Temperature Heat Gun


this pics after a short cleaning on buffing weel





my two cent
________________________

Riccardo Mainolfi
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Riccardo, You are a real belt and suspenders kind of guy. We are not worried about your pants falling down.

Having just gotten that ugly guard off my knife I'm not worried about any guard with a solder joint as good as yours every moving. I would, perhaps, worry about guards installed with JB weld. I'm sure I could have popped my guard off with one hammer blow if it had been JB. As it was I cut a slot in the top of the guard and forced it away from the blade with a large cold chisel. It took a little work to get it to pop loose.

Final comment/observation and I hope this doesn't offend anyone: I trained with Ed Fowler and Ed drummed it into my head that I should never create any "stress riser" in a blade. A hole through the blade and guard would be a stress riser and if the pressure were severe enough I would expect the failure to occur right inside that guard.

With a knife finished as beautiful as yours I doubt anyone would put it to such hard use unless they had to do so to save their life.
 
another thing that can happen is if the blade is at the melting temp and the guard has not reached it yet, the blade will melt it and it will just ball up on the guard face.
colu41 said:
What does it mean when the solder sort of balls up on the surface rather than flowing? Does it need more heat? More, less flux? Im slowly trying things and I can get the solder to fill in the cracks but, it's not turning out very pretty. Not the nice seam that it should be.
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That may be it. Seems like that could be the issue. I am hitting underneath the guard more than the guard itself. I'll try it out again.
 
Just did one tonight that frustrated me. I didn't have the guard fitted as tight as normal. It was a ready made cast guard and had quite a taper in the slot.
When I heated it the guard expanded and when i touched the solder to it it shifted just enough that the handle I worked so hard to fit no longer seats against the guard. Guess there will now be spacer material between the guard and the grip. Yawn.
 
Riccardo, when you use the heat gun, do you aim it more on the tang side and towards the guard? How long does it take to bring the material up to temperature? Also, thanks guys for the heads up on the video. I got it from Palladin press, well worth the price.
 
A.F. Holowaychuk said:
All I can add is reinforce an earlier point, which is do NOT do your first try on a knife.

I tried soldering a guard onto my second knife (blade pointed down, fluxed, heated the tang/guard with a torch just enough to get the solder to melt, then applied solder), I was using regular leaded solder, 60/40 I think. It melted right down past the guard and all over the blade. Huge mess getting that apart, getting the solder off everything, started over on the guard and blade finish... I clearly messed up in almost every possible way! So yeah, practice on something else first. I'm gonna stick with epoxy for now!
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Next time put some silicone on guard / from the blade side of course / and solder will stay where you need it .
 
also pay attention to heating the guard lugs just as much as the body of the guard. i dont mean hold the flame on them for as much time as the body of the guard, because they heat up quicker. just quickly wave the torch on them every few seconds while heating the tang/guard body. if you are just heating the blade/guard intersection those lugs will draw the heat away.
 
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