SOLDERING HELP

M

mikekc130

Joined
Jul 24, 2000
Messages
15
Used Kester lead free low temp silver solder (listed as melting at 430 degrees).

Both guard and blade are from the same peice of 440C. Both blade and guard faces polished to a 400 grit level.

I cleaned both with acetone then hot soapy (Ivory dishwashing liquid) water then dried in the oven at 250 degrees for 20 minutes.

On the first attempt I left the guard in the oven for another 1/2 hour while putting the blade in the freezer so I could drive it on.

Touching only the blade and guard edges I drove the guard on, held the guard in a vise then applied heat stop compound approx. 1/4" above the guard. I applied the liquid flux then applied heat from the handle side directing the flame at handle vice the guard. As soon as the flux started bubbling on top of the guard I applied the solder to the joint line on the blade side. The solder just beaded up w/o being wicked into the joint.

The 2nd attempt was almost the same procedure. After clean up I opened up the clearance enough to where I could drive on the guard while both pieces were still at oven temperature. I figured that wter had condensed in the joint thus contaminating it. The results were the same!

Any help/suggestions would be much appreciated.

S/F, Mike

 
Yeah I have had the same problem. It seems that the flux that comes with that solder isn't that great. What I do is clean up with a spray electrical cleaner fit the parts. I use a very small hair type paint brush to put on the flux. If your solder beads uppaint some more flux on right away and re heat. I use a small forecips with a small ball of steel wool to wipe the joint with to help remove excess solder
Take Care
TJ Smith
 
I don't know if it's possible, but maybe your joint is TOO tight? If you have to go through all of that temperature trickery to fit the guard to the blade, there simply may not be enough space for the solder to capillary into the joint...

I don't know if this is even possible--anybody, can you back me up or clear me up? It seems like everyone I know wants the guard to fit snug, but basically you should be able to fit it up either by hand or with a few little taps.

Of course, if you have that close of a fit, maybe you don't NEED to solder it...pop a pin through that sucker, and move on! Just a thought...

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Vaya con Queso!!!
 
I'd have to agree. I enjoy making solderless gaurds on my knives, so if your doing that good of a fix maybe it's the way to go.
J.
 
Appreciate the replies. I want to use low temp to minimize heat treat deltas. I also want a water proof joint.

I had passed on doing a MIG weld since I had already had the blade heat treated and I wasn't sure about completely filling the void.

I'm going to try and again with Allstate brand, open up the slot a little, and clean with contact cleaner after the acetone. All per Joe Flournoy.

S/F, Mike
 
Has anyone tried 'tinning' the knife and guard then just heating the combo to assemble. Seems like it would be a good way of assureing complete coverage.
Comments and flames welcome.
Thinking again, Lynn
 
Soldering stainless to stainless is quite a challange. In my experience, most knifemakers solder brass or nickle silver guards on their knives.
Having said that, Stainless guards can be soldered to stainless blades. I have soldered 416 SS guards to ATS-34 blades hundreds of times.
I use Allstate 430 solder and flux. You can get it from Pop's. His phone number is 706-678-5408 (call between 4:00 - 8:00 PM Georgia time.
I also use a 200 watt soldering iron. I use a syringe to apply flux the blade and guard. Then I apply the soldering iron to the bottom of the guard. When the blade and guard start getting hot, I apply the solder to the soldering iron. (I hold the soldering iron under the guard). I use a one/16 SS rod which is sharpened on one end to apply flux to the top of the guard, and to drag the solder around the joint once capilary action has pulled the solder up from the soldering iron.
It takes practice, and I could show you a lot easier than I can write about it, but it can be done, and makes a watertight seal around the blade and guard.
You are right to really clean the parts to be soldered. With stainless, you can't get them too clean.
I would suggest that you leave a bit more clearance between guard and blade. You might be getting the fit so tight that solder can't get between the guard and blade.
I don't use the heat paste. I found that flux reacts with it and etches the blade where I don't want it etched. Yes I know it's not supposed to do that, but it sure did it for me.
Instead, I took two pieces of aluminum three eights of a inch thick. I put a hinge on one side, and a clamp on the other. I clamp this on the blade and it absorbs the heat and keeps the cutting edge from getting too hot.
Hope this helps. Tom Lewis
 
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