Need help soldering stainless!

T

the possum

Joined
Jul 31, 2002
Messages
2,954
AAAAARRRRRHHHHHHH!!!! I've about had it with this stuff! :mad:

I cannot get solder to stick to this stainless Bowie blade (tried many times) I just got back from Paul Bos, and I can't figure out why. Let me describe what I'm doing.

Blade is ATS-34 @ 56-57 RC, guard is yellow brass with tight fit. Solder was Stay-Brite silver bearing solder with liquid flux obtained from Atlanta Cutlery several years ago. Guard (and rest of blade) area was sanded completely to 320 grit finish and washed with soap and water. Fingers were also degreased, and the guard area was never touched after sanding. When the blade was rinsed with water, it cascaded evenly over the surface, indicating no grease. After this prep failed, I repeated the procedure, and this time also degreased the guard area with Brake Cleaner solvent. No luck. I was using a propane handheld bottle torch to heat the whole guard area. I had the blade resting on a charcoal block to help trap the heat and insulate the blade. I held the flame on the underside and far sides of the guard area, so the steel was evenly heated all the way through. I did not apply heat directly to the solder, but put the solder on the rear of the guard joint and heated from the front, so the solder would flow toward the heat. I cleaned the wire of solder with steel wool beforehand, removing all oxides. I tried fluxing both before applying heat, and I also tried applying the flux with a pick just as the solder started to melt. No luck. I removed the guard, and sweated solder into the entire inside of the guard, basically "plating" it with solder, in an attempt to sweat the guard on. I should note I had no trouble getting the solder to stick to the brass. It flowed nicely on the whole inner surface of the brass, and I didn't even really clean the guard as well. After more frustration, I just removed the guard and tried all I could just to get some solder to stick to the bare stainless blade. After all kinds of cleaning, trying several fluxes, different heating methods, applying the solder differently, (tried chips of solder, pressing the wire of solder onto the hot steel, and spreading molten solder with a fluxed pick) and different fluxing methods, I could only get the solder to stick in a few small patches.

What the hell am I doing wrong?! I'm beginning to think I just don't have the right type of solder or flux. Now, I should also mention I'm fairly familiar with all the theory behind soldering from a few metalsmithing courses I took in college. The grad assistants even called me "solder god", and we were doing hi temp solder with silver and gold, which I'm told is MUCH more difficult than low temp soldering. But I just can't figure this one out. Help!
 
Did you by chance buff any part of the blade/guard before attempting to solder? If you did, it is contaminated. It's very hard to get that stuff out. It's almost like it's impregnated in the steel.

The best way is to sand the areas you may have buffed, including the guard, inside and out, then clean with acetone, followed by hot water and dish soap. After that, do the same thing with 409 cleaner, rinsing with HOT water. Same with the guard, including inside the slot.
Again don't touch anything. When you go out to solder, wrap a wet, not dripping cloth around the blade, just above the guard line. I hold mine on with mechanics wire.
Take a cotton swab with flux and wipe it around where the guard is going to be, followed by doing the same inside the guard slot.
When you heat, make sure to get the flame on the guard, as well as the tang, all around. Don't heat until the flux turns black. If you do that, it means you got it to hot, and you have to remove all the residue and start over, as the solder will not stick properly to it.
When you get the solder to flow, dip a sharpened instrument into the flux, I use an old ratty round needle file, and draw it around the seam. Make sure to heat the tool also.
That's about all I can say on the subject. These things work for me. Maybe someone else has a better idea. :confused:
 
Mike's question sounds good to me, and I would also ask if you might try a fresher flux (as mentioned above). You say you tryed wetting the stainless by itself with little luck. Go down the tang, sand the sum-beach there, clamp the ricasso in a flat jaw vise to protect your blade and pour it to it at the tang spot you chose. It's gotta wet if the flux and solder is okay. You know how to and I know ATS-34 wets, so something else is a-mis.

Keep the ricasso firmly clamped so as to protect your temper.

Roger
 
southriv, I looked both tutorials and I wonder if I risk to break the tempering of my blades when I solder the guard like on the tutorial ? It seems to to me that heat must be spread in the blade? I think that 440c have a low tempering temp ?

Alain M-D
 
Great advice so far. It sounds like your flux may be the problem. I use the lid off a pop bottle and put a little flux into this when I am soldering so I don't contaminate the whole bottle. This small amount gets thrown away when I am done. Once your flux is contaminated it goes bad pretty fast.
If you decide to get new flux I think I would get new solder also. No I don't think your solder has gone bad I just like eutectic 157 silver solder. It seams to work better for me. Kovals has it available in small amounts. Their number is 1-800-556-4837. 1 oz. is 14.95 plus shipping.
I would also try cleaning your blade with acetone.
Good luck

Tom
 
Alain - I apply the flame from the back of the guard at a 45 degree angle so it hits the guard and the tang. When the flux starts to boil, it's my signal that the solder will melt in a second or two. I also use a heat absorbing paste. With these two cautions I've never had discoloration or excessive heat transfer.

Bob
 
Once again, Tom Krein speaketh the truth. :) The solder and flux combo sold by Koval in the little pink bottle works very well for stainless.
 
Originally posted by Alain M-D
southriv, I looked both tutorials and I wonder if I risk to break the tempering of my blades when I solder the guard like on the tutorial ? It seems to to me that heat must be spread in the blade? I think that 440c have a low tempering temp ?

Alain M-D
Click to expand...

Alain, I use a lot of 440C, I just wrap a wet washcloth around the blade, just above the guard line. See my post above. Never had any discoloration.

I prefer this method, as I have had pitting from heat absorbing paste.:mad:
 
Soldering SS is just plain a PITA, period.
One thing I'm not clear about, did you use StayBrite's flux, too?
The flux is best matched to the solder, and ,makes a big difference.
Cleanliness, as mentioned, is paramount, but then you know that.
One thing i have found is that I rinse with acetone last and let air dry. We have really hard water here and the minerals will leave a film that can inhibit soldering, too.
I have found with ss the temp has to be just right, both the blade and guard, at the same time, and if that flux bubbles long it won't work. Have read, too, that overheating is a common problem for the solder not sticking. I had so much problems with using a big torch, and overheating, that I went to one of those little piezo-fired tiny butane torches one can get for cheap on e-bay or for about $30 at Home Depot. That pinpoint flame made a big difference. I heat with a bit of flux around then have to swipe it again just as I am going to apply the solder.

Good luck. It's not the easiest thing to solder, but you'll get it, because it CAN be done.
 
Originally posted by fitzo

The flux is best matched to the solder, and ,makes a big difference.
Click to expand...

Right on, Fitz, I couldn't have said it better myself.
 
Or just give up and do a "Harley". Use epoxy on the joint. I do that with stainless.
Lynn
 
Thanks for the help, guys. I origionally believed there was a problem with the flux, and you guys seem to support that idea. I was using the flux that came with the solder, and it's in a dropper bottle with a tiny pinhole in the tip- I can't understand how it could have become contaminated- but it's worth a try. I did try using some paste flux meant for plumbing, and that didn't work either.

"Did you by chance buff any part of the blade/guard before attempting to solder? If you did, it is contaminated. "

No, I don't even own a buffer, so I guess that's not the problem.

"The best way is to sand the areas you may have buffed, including the guard, inside and out, then clean with acetone, followed by hot water and dish soap. After that, do the same thing with 409 cleaner, rinsing with HOT water. Same with the guard, including inside the slot."

Yeah, I sanded the guard area of the blade down to fresh steel, washed with soap & water, and cleaned with brake cleaner,(our mechanic told me the brake cleaner was acetone) but I didn't try anything like 409... yet. I should mention I had zero problems gettin solder to stick to the brass guard, and I didn't spend half as much time cleaning it.

"Don't heat until the flux turns black. If you do that, it means you got it to hot, and you have to remove all the residue and start over, as the solder will not stick properly to it."

Understood. The flux did not blacken. And I did try using a soldering pick as well. Please don't misunderstand me here, I'm NOT trying to pick on you or anyone, and I don't want to come across as a know-it-all. I'm just trying to make sure we all know which potential problems we can rule out, so you guys can help me better. :) For instance, I didn't want to get ten replies saying to clean off buffing compound better, when I never buffed in the first place. I hope you see what I mean.

Maybe I should try the solder mentioned from Koval's, but I'm so dang poor right now, I'd honestly have to save up for a month for a $15 item. I just spent $80 to have a blade custom heat treated, and that was a few months' savings. Ya know, this knife is just a "beater" anyway, and the seam is pretty small. Maybe I should just forget about it.
 
soldering.........much like blade grinding........is a process that takes quite a while to master, and even then you must be very careful on EVERY SINGLE knife to get it right. For well over a year I wanted to pull my hair out every time I had to solder a guard on, but eventually I figured it out and now I can routinely get them just the way I want them to be.........22 years later! :p
 
Possum
Did you just say you spent $80.00 dollars getting one blade heat treated. Your joking right!

Tom
 
Originally posted by Tom Krein
Possum
Did you just say you spent $80.00 dollars getting one blade heat treated. Your joking right!

Tom
Click to expand...

At the risk of taking this thread off topic, I'm gonna bite. Yeah, I spent $80 to have one blade heat treated. (including shipping) It was a 24" long Bowie ground from 5160. I asked around here for someone willing to do it for me, and got a very, very generous offer from Mr. Bruce Evans. (or was it Bruce Bump? I'm pretty sure it was Mr. Evans. this is embarrassing.) Although, his method wasn't quite what I was wanting, so I declined. I guess time will tell whether that was a bad decision. Rather than having the usual differential harden via edge quench, I decided on a salt pot marquench that would result in a blade of solid bainite. Several knowledgeable smiths I consulted believed bainite would be better for my purposes, since this knife will be used mostly for heavy chopping, but will never really get dull from normal cutting. (the edge will be nicked and damaged & need sharpening long before it gets "dull".) The smith I sent it to was the only one I could find willing to do it, and I expected to pay him more for his services since he doesn't heat treat blades in batches of 500, but rather has to take several hours of his time and equipment expense just for me. I realize I could have had it done much cheaper if I wanted to settle for an inferior "industrial" heat treat, or if I wanted a martensite edge with a pearlite back. I put a lot of time into this knife, and I nearly cried when I broke my last big Bowie knife, so I just wanted to make sure that won't happen again. I guess now I'll just have to see for myself.
 
You must log in or register to reply here.
Back
Top