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Daniel chapa

How to solder gaurd to a knife

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I tried soldering a gaurd to my knife but the solder was not sticking. I was using g that silver solder and a propane torch. The gaurd is mild steel and the knife is a coil spring. Any tips or can someone tell me what I'm doing wrong. Ill put a pic up later the metal is still hot

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I am the worst at soft soldering, adolescent chimps do better, I have been told "clean the area well, scuff it with coarse steel wool, clean again, pre heat if the material will take it, flux well, solder, leave it the heck alone until it fully cools." I have added, for my own benefit " get the handle on quick before something goes wrong".

Sorry I'm not more help

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It's all about cleanliness.  The flux is important to maintain the cleanliness. 

Clean the parts very well, which wold include sanding/filing to get to clean scale free material.  Apply flux, and then heat it until the solder flows.  I prefer to not have the solder in the torch flame, and test for temperature by moving the flame away, and touching the solder to the joint.  When the solder melts you are there.

If the solder is melting, but not sticking, you either have a surface contamination, or you got the solder hot enough to melt, but didn't get the steel hot enough for it to stick to.  What kind of flux are you using?

 

 

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What Brian said.  Also, if it balls up and rolls off that usually means it's too hot.  Finally, it's not silver solder.  It's silver bearing plumbing solder.  Actual silver solder flows at over 1000 degrees hotter.

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Just now, Daniel chapa said:

It's the plumbing kind

In that case I might have a few tips.

I had much better results after I started using two pieces of aluminium angel either side of the blade then clamped into the vice.  I need to shim mine on one side to get everything level.....needless to say that's necessary.

My theory is the aluminium forms a bit of a dam.

Secondly, even though alu is used for heat sinks, I get the feeling it stops the vice from sucking the heat out of the piece.

As far as possible only heat the guard, might also help pre-loading the guard with solder.....

I always work blade clamped and tang up so it you interfere with the temper it's not the blade.

Rather too much than not enough solder, I use a beater knife to cut and scrape off the excess.

I've only used brass and copper which are easier to solder, but I believe mild steel is possible as well.

38 minutes ago, Daniel chapa said:

When I tried the solder bubble and rolled off 

Generally means the piece is not hot enough....what Brian said, get flux.

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Ugh, I've tried this several times too.  I've had the most success by using a silver solder paste where both the silver solder and flux is premixed together. 

I've also noticed that there should be no direct flame on the solder, heat the components very lightly and indirectly.  Heat a corner of your guard or tang not the actual joint. And keep in mind solder flows toward the heat.  For steel, I always lay the solder on the joint and attempt to bring it to temp, once it liquefies, pull the torch away immediately.  If the solder has turned into little beads, then yep it got too hot, they will not have stuck.  For some reason I've always noticed when I tried this that the steel has a very small window of hot enough and too hot. What's funny is that it will seem to ball up and roll off like it's mercury. 

I've only got steel to steel joins to work about 3 times, one on a knife and 2 others where trial pieces.  It seemed to me that if you were able to make a pool of solder and stick something in it and allowed it to cool it worked pretty well.  Trying to use it like your sweating two things together like plumbing - I've had little success with that. 

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2 hours ago, Daniel chapa said:

What's flux?

Anything that prevents oxides from forming when heated.  The place where you got the solder will have jars or tins or tubes of zinc chloride soldering paste flux.  Don't look at Cliff's link, it's just for jewelry work and you're confused enough as it is. ;)  With your blade and guard CLEAN and fitted as tightly as possible, since soft solder will not fill gaps, smear a small mount of the zinc chloride on the joint.  If your solder is in thick wire form, hammer it into this strip form and rub some flux on it as well.  Gently heat the joint, and as has been said, don't point the flame directly at the joint.  The flux will melt and smoke.  When you think it's hot enough, take the flame away and at the same time touch the thin solder to the joint. If it doesn't immediately flow into the joint, take it away and add a little more heat.  Never heat the solder itself directly with the torch.  And be aware that once you see the solder flash into the joint, stop immediately.  Let it cool completely.  If you keep on letting it flow after it flashes into the joint, you will discover huge blobs of solder all over the other side of the guard and the blade.  This is a pain to remove.  If you touch the guard before the solder sets, it will fall off and you'll have to start all over.  

All in all, there are number of good reasons soldering guards was never used historically.  And yes, I mean never.  Not until the 1950s, in fact, when Bo Randall and Bob Loveless started making knives.  They were coming from a machinist background and had no concept of the history of cutlery manufacture, and since they didn't know how it was supposed to be done they invented a whole new way to do it.  I'm not saying it was a bad way, the guys were great and the entire custom knife world as we know it wouldn't exist without them, but knives did manage to exist for a couple thousand years before anyone ever thought of soldering on a guard.   Just something to think about. B)

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No, if it's split you're pretty much stuck with soldering, sorry.  If you're good with a drill press you can cross-pin it, I've seen some early Bowies done that way.  My first knife had a split guard and is soldered, which is when I learned to do stick tangs. :lol:

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Unless by doing so you forge-weld it, I doubt it would hold.  And that's exactly how the Spanish Belduque was made, welded-on guards and bolsters.  If I were you I'd keep practicing on the soldering, it's a useful technique.  I did not mean to imply earlier that it isn't a good method, I was just mentioning when it came to be a method.

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Stick with it Daniel, and you'll get the hang of it.  I solder my guards because I find it easier to do than other methods.

I came into knife making with soldering skills already in hand, but didn't always find it easy to do.  I remember when every time I tried to solder something, I ended up with a hot black mess of parts that stuck to everything but each other.  Then one day it just clicked, and I couldn't understand why I ever struggled with it.

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