Soldering Guards

colu41

colu41

Joined
Dec 24, 2014
Messages
1,598
I found an old soldering iron in my garage that my father in law gave me, and played around with it last night. I simply tried soldering a small piece of cpm154 to another small piece of 1095, and couldn't make it stick.
Now I will be attempting my first slotted guard soon, and from my understanding will need to be soldered.
Is it the type of wire? I also read of some type of paste needed?
If someone could give me a few pointers of what I would need to solder 416 to either stainless or carbon steel, that would be great.
 
I could be wrong, but I believe that common use of the term "soldering" for guards is related to using silver solder that has a much higher melting point than common soldering wire for electrical applications, and also is soldered using a small jeweler's torch (i.e. Little smith torch) as opposed to a simple soldering iron.

Silver solder should come in hard, medium and soft hardnesses and each have a different melting point...my guess would be that a lot of bladesmiths use the soft if they have the choice but not 100% sure on that. I always use the "hard" variety since I have a lot of it and it works for me.

What I've found in soldering with silver solder and a jeweler's torch is that the working pieces themselves absolutely have to be at the proper heat for the solder to flow correctly. If you just focus the flame/heat source of choice on the solder itself, it just balls up and doesn't want to go anywhere or sputters and looks crappy.

In past pieces that I've done, the soldering works best when the pieces being soldered are at a dull red heat. If anything, the flame is first focused entirely on the working pieces until they're at temp and then you can focus the flame on the solder itself (if it hasn't already flowed into place from the ambient heat of the entire working piece).

Also, the solder is drawn into tight spaces due to capillary action, so there should ideally be a tight fit between the pieces being soldered. I believe Mete commented in a post a while back with the ideal "gap" distance for capillary action to work the best. And of course, flux anywhere that you want the solder to flow before heating.
 
Awesome info, thanks! Now you say the pieces need to glow red. How do you prevent the guard face & blade from over heating and turning colors?
 
True silver solder requires temps around 1000f....that's not what you want for
guard soldering.
What most makers use is a silver bearing solder....typically flows at around 430 deg f, and usually
requires the use of an acid flux.
Also....unless your soldering iron is 150 watts or higher, it probably will not produce enough heat volume
to heat the parts sufficiently.
 
you don't need near that much heat--they key is clean parts and plenty of flux--your solder should flow by capillary action into small gaps where you have fluxed, and bring the material to be soldered to a temp high enough to melt the solder you have held up to the edge of the joints to be filled--whenever you have the to be soldered parts hot enough to cause your silver solder to melt, it will start flowing!
 
ONeill said:
no no , no red , that works for copper .
Click to expand...

For a softer silver solder, would a small butane touch work? It has a very precise flame and if hot enough, I think would work great. Im just afriad of discoloring the blade above the guard, and the guard itself. But, whatever I need to buy I'm up for it.
 
Thanks guys. A lot of info in just these few posts. :) Today or tomorrow will be going out to look for the some new solder and flux. Will be practicing on some scrap first but, initially will this work with (stainless to carbon) (stainless to stainless) (carbon to carbon)? I'm sure its not bonding like a weld but, just seems strange to me. I guess I just dont understand soldering as I've never really done it. I've only ever used an actual soldering gun to stipple my Glock :D.
Does it just fill in gaps? Or does it actually bond to the metal?
 
Soldering is an adhesive, unlike weld which is a fusion. It will fill tight gaps but trying to bridge large gaps with it is ugly and hard to do because of the aforementioned capillary action. You also need to be careful that you don't allow the heat to travel up past the bolster or guard too far into the ricasso because the solder will follow it and be stuck in a visible prominent location that is hard to remove.
 
To be honest I don't know if their is an actual bond created to the metal parts when you solder--it is damn sure stuck on there to the degree that it has to be chiseled or sanded off if needed removed, maybe Stacy or another more metallurgically (?) more knowledgeable member will weigh in one this--as to what kind of metals it will bond together, all I can tell you is that I have used it one Carbon/Carbon, Carbon/Stainless, Stainless/Stainless Stainless/Brass to good effect.
I think your butane torch should work, I haven't ever used one, but I don't know that my mini propane one runs much hotter than those butane ones--perhaps if you do a little digging around, you can find out how hot the mini-propane ones run, and how hot the butane ones run--and that'd give you some insight.

Good Luck
 
kuraki said:
Soldering is an adhesive, unlike weld which is a fusion. It will fill tight gaps but trying to bridge large gaps with it is ugly and hard to do because of the aforementioned capillary action. You also need to be careful that you don't allow the heat to travel up past the bolster or guard too far into the ricasso because the solder will follow it and be stuck in a visible prominent location that is hard to remove.
Click to expand...

GOOD INTEL BY kuraki
 
Thanks Kuraki & Fish. So it makes me think, with a slotted guard, I would be milling it out to have a pretty tight fit. How much will the solder actually flow in the microscopic gap that will be there?
 
Ah, I apologize for the misinformation, seems that that applies only to non-ferrous metals and not steel :foot: I've done some mult-piece non-ferrous guards that I then epoxied along with other components, but never soldered the guard straight to the tang. I believe for the high-temp route, "brazing" would have been the right term, and would use brazing rod as opposed to the silver solder. Curious as to whether more people choose the low-temp solder vs higher temp brazing.
 
Hey Colu41, I was poking around on YouTube today, and I ran across this vid from 'BowieMaker' and it is good to watch re: soldering guards---he states at some point that the silver solder he is using has a melting temp of 300 degrees, so obviously you need to have a torch that will run a good deal hotter than that--he uses a standard propane torch, which I have used myself, as well as a mini propane torch. You can jump to like 16:15 in this vid clip, and you'll see everything I think you would want on guard soldering. Here's the clip: https://www.youtube.com/watch?v=RPkd4h2iXNk

Good luck!
 
good video. i recommend soldering from the bottom. much less cleanup at the ricasso/blade junction.
 
O'Neill, my thought is that the lighter fluid supercleans the area where you want the flux to go--and thereby the solder. I have used that approach and not, couldn't tell much of a difference, but I'm pretty anal about only soldering clean surfaces....
 
There is some bad information here.
I'll attempt to explain.

What you want for guards is silver-bearing solder. It contains around 4% silver. This silver content allows the solder to adhere to both stainless and carbon steels-as well as non-ferrous metals.

A soldering iron will not have enough heat to solder a guard. The cheapest was is to buy a standard propane torch at a hardware store. You can usually get your solder there, too.
The metals in the joint have to be fresh metal-filed or sanded bright. This is very important. The joint also must be clean, but most people make too much of the cleanliness.

Apply your flux to the joint, then heat with a GENTLE flame from the torch. You only want to get the pieces hot enough to melt the solder. Apply solder to the joint, and it will flow into the joint. Remove heat as soon as the solder flows.

After the joint cools, wash it with soapy water and dry.

Do not try your first soldering on a knife. Use scrap pieces to practice. Also- be wary of using things like a vise, which will act as a heat sink and prevent the joint from getting hot enough.
 
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