HELP:Loss of hardening with handle solder work

R

refinger

Joined
Mar 3, 2010
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4
I'm a new (would be) knife maker and got a little ambitious on my 3rd knife and did some silver soldering on the brass bolster that I am pretty sure took the hardness out of the adjacent area of the 01 steel blade that I had hardened and annealed. I hate to "undo" the pretty "successful" work I did on the bolster...is there a way I can re-harden the blade without losing that brass and silver solder work on the bolster? I thought of re-heating the blade while the bolster and rest of the tang area are immersed in a can of water or oil but this seems weird and unlikely to succeed (heat transfer issues?) ... any advice (or genteel hoots of derision) are welcome and appreciated. Thanks, Rick
 
You said "hardened and anealed"....did you mean "hardened and tempered"..?

Are you using a true silver solder, or a tin, silver bearing solder..? The former
will flow at something at or over 1100F, where the latter will flow at around
430F. The latter is preferable.

To re-harden, youll need to remove the bolsters (brass melts at 1550F or so), and
your steel needs to soak at 1525-1550F. Youll also need to remove ALL the solder.

....essentially, start over...
 
Thanks...that's what I was afraid of....oh well this is how I (at least) learn...the hard way. I appreciate your wisdom on this. Rick
 
What color did the blade steel get to, and how far down the blade did the colors go?
If it didn't change color past the ricasso, I'd not worry about it.
 
I had the blade covered in aluminum foil and layers of blue painters tape and the tape burned on to the blade (please remember I am new to all this) and that obscured the effect on the blade. The situation is exaggerated by the fact that it is a boning knife and the blade is quite thin and narrow. I appreciate the advice and I think that I will assess it carefully before deciding. These are learning trials for me and I am certainly learning. Thanks again. Rick

(I meant "tempered" and not "annealed" in my initial post)
 
Next time skip the foil and wrap with a wet rag to keep the blade cool. To prevent this problem cut some small pieces of solder and place next to the joint, apply heat from the bottom (tang end) and just until the flux starts to bubble, remove heat and give the solder a second or two to melt, if not heat a little more and remove the heat. If the flux starts to brown its too hot. Once you do this a couple of time you will get a feel for it, it takes a couple of seconds for the heat to reach the solder. You can help the solder spread even with a sharp brass rod.
 
Patrickknives said:
Next time skip the foil and wrap with a wet rag to keep the blade cool. To prevent this problem cut some small pieces of solder and place next to the joint, apply heat from the bottom (tang end) and just until the flux starts to bubble, remove heat and give the solder a second or two to melt, if not heat a little more and remove the heat. If the flux starts to brown its too hot. Once you do this a couple of time you will get a feel for it, it takes a couple of seconds for the heat to reach the solder. You can help the solder spread even with a sharp brass rod.
Click to expand...

Great description Patrick!
 
Thank you Patrick. I just did a practice run on some scrap using your suggestions and it worked pretty darn well...I am sure I will get better at it as I have more experience with the solder. Lots of of techniques involved in this work and I truly appreciate the help.
 
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