#$@! Soldering just intimidates me

G

godogs57

Joined
Apr 16, 2004
Messages
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I still cannot figure out why I can solder some knifeguards and others absolutely not...no way...no how. Working on a chute knife today and ended up having to solder it three times over an hour to get it to work. I know every trick known to mankind to solder and it just wont consistently work for me.

Heat from the bottom so it will draw it down? Yep.

Don't heat too fast and burn the flux? Yep.

Use a good silver solder recommended by other fine folks on here? Yep.

Flux often? Yep.

Clean up all joints good before soldering? Check.

My solder runs all over the place EXCEPT down in the crack where it is supposed to in some places. I can't figure it out. I hold my propane torch below the guard, heat it nice and slow after fluxing and one side of the blade behaves great...go to the next side and 80% of that side behaves like it is supposed to but that little remaining bit you can pour the solder to it and it will run away from that little remaining crack.

I am going crazy over this....

Help me before I jump off the nearest bridge.
 
You didn't say what metals you're working with, but.....

If either or both are stainless, I'd recommend tinning the parts first,then
wipe off as much as possible while still "wet". Make sure all acid flux is
cleaned from parts.
Assemble cold. Place a small piece of solder on the face of the guard, near
the joint and begen heating slowly. When the small piece of solder melts, remove the heat
and apply rosin flux, followed quickly by small amounts of solder. The heat and flux will draw the solder through the joint. If any small amount of rosin flux remains in the joint,
it will not eat it's way out as acid flux can. Reheat gently, as needed.

NOTE" A small piece of steel or brass rod (1/16") can be used to help move the solder
where you want it, and (if tinned) can also be used to apply small amounts of solder.
 
For the best strength and necessary capillary action the gap should be .003" . Take the time to fit things very carefully !!
 
Good info above. I also add more flux if the solder wont flow.

Stainless steel can be a real pain in the ass to solder...
 
I would use Only medium flow silver solder and a good flux, you ask for problems later with lead solder. Get a small bottle of yellow ochre, as it will keep the solder within its boundaries when applied properly. Without good flux, stainless will exude black impurities into the flux fast, if that happens, re-clean and start over.
 
Forgot to mention....blade is CPM154CM and nickle silver guard. Little aggravating spots like I was referencing above, I refluxed multiple times and the stuff still wouldn't flow.
Finally got a good bead all around after using about a foot of solder (not kidding) through my 3rd attempt.

Also, what does Russ mean by "tinning"...and is Rosin flux the preferred flux for everyone? Just asking....I want to get this monkey off my back. Thanks for everyone's help...it is sincerely appreciated!
 
Tinning means to coat the surfaces to be soldered with solder
before assembly, so that when you do your final soldering you
are soldering solder to solder.....not stainless to whatever.

Using an acid flux for tinning, and a rosin flux for assembly is not
a process used by everyone. I began doing it because rosin wasn't
aggersive enough for SS, and acid would eat it's way out if any
were trapped inside the joint.
 
Solder is not like welding. I don't think are getting your blade and guard hot enough to cause a capillary action. Direct your heat to the guard and let the heat transfer to the blade just to point it pulls the solder into the crack.
 
Make sure the flux states 'for stainless steel' !! Typical solder for stainless is 95Sn,5Ag
 
Ok, gent's, I have decided to put the task of soldering on guards and bolsters on DVD, watch for it, as it's the only way I can show how it is easily done, now to find a video cam..

Mete is right on too.
 
The trick I use is follow everyones advice, I cut small pieces of solder and place next to joint, really small, every smaller. Heat remove heat let melt. I then use a 1/16 brass rod that has been shapened to spread the solder in the joint, I dip into the flux and spread the melted solder. The solder when facing stainless likes to ball up and this somehow makes it go ahead and spread and get sucked into the crack. I just did 4 guards on 2 subhits of ats34, very little clean up.
 
One other suggestion, the blade and guard need to be "Really" clean. I use Ivory dishwashing soap and hot water.
AllState 430 solder and flux works on stainless, brass, and nickle silver.
 
Jim I must confess....I have made knives for 28 years and have yet to have he first guard I soldered on to show any type of capillary action....I have never seen solder sucked down towards the heat source! I know it happens because every "how to do it" article or thread tells me that's what will happen.....never ever does for me.

Just a mother fluxin' mess...that's all I get!
 
godogs57 said:
Jim I must confess....I have made knives for 28 years and have yet to have he first guard I soldered on to show any type of capillary action....I have never seen solder sucked down towards the heat source! I know it happens because every "how to do it" article or thread tells me that's what will happen.....never ever does for me.

Just a mother fluxin' mess...that's all I get!
Click to expand...



Have you ever sweated copper pipe?
 
I'd suggest getting the SR Johnson subhilt fighter video. He doesn't use a torch, he uses a heat gun and a lower temp solder. It shows everything he does in great detail.
 
Like Russ I "Tin" both parts first. Its easy to do the parts separately and then just put it together and add just a bit more heat and brush it around. I havent had much luck with a heat gun.
 
Thing about soldering is, it is not welding. The workpieces have to be totally clean of any oxides, the joint has to be perfectly tight, the whole joint area slathered in flux, and then, contrary to your experience with gas welding, the entire area, not just the joint, has to be heated-- but not so heated as to be overheated and burn off the flux before the workpieces come to soldering heat-- else the heat will run away into the adjacent steel. Solder will fill a crack, contrary to what the textbooks say, but it will have no real binding strength except where the two pieces are touching.
 
Soldering is a pain. I no longer do it. I pin all my guards on now.
Scott
 
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