Soldering Stainless: The Breakthrough

R

rashid11

Joined
Dec 8, 2005
Messages
707
Some of you might remember my rant about failure
to solder 304 guard to ATS34 blade. Some of youz might've
had truly miserable experience yourself (some to the
tune of going for 8hrs straight :eek: ).

I didn't like 304 for another reason: it is really tough
to work with :thumbdn: . Fortunately, it's little brother: 303,
has sulfur added and is rated @ 70% machinability :thumbup: .
I got me some. McMaster, of course. :rolleyes:

So this morning, as 100F weather finally went away,
got into my workshop.Cut off a smallish piece of 303,
sanded on me belt grinder to something like 300 grit.

Into workbench vise it went. Got my stainless flux
(mcmaster, of course - it is weak hydrichloric +
some zinc) and silver solder (same place, 5% silver
+ 95 tin, food safe).

Acid brush, dipped into flux, smeared onto the metal.
Blow torch, warmed it up, from the OTHER side of course,
brought solder wire in contact with metal piece.
Solder melts, beads up and down the metal it goes. Doesn't
wet the darn thing at all ! $*(!&!($*#%&(*@& %(*@#&$ !!!! :barf:

More flux, sanded the solder wire (it looked plenty shiny to me), just in case there were oxides/dirt/oil whatever, same excersize, same result ! :grumpy:

Desperation setting in ... :mad:

And this is where a piece of sheetrock falls off the ceiling
and hits me square on the head ! Not really, but I decided
to dip the SOLDER itself into the bottle of flux. :confused:

And instant success ! The second I touched that ,wet with flux,
solder wire to the hot 303 metal, the darn thing wet all over the place !!! :D

I dunno what it does, really - may be there ARE some oxides/oils on the solder
and that causes the bead-up/lack of wetting action. Or, may be, as I heat up
the metal AFTER smearing it with flux, some of the ingridients break down ...
Dunno . But it surely worked great !
 
Never had a problem like that. I use staybrite solder and flux. Or used to, I hard fit guards now, no solder.
 
Congrats. In my opinion you use solid solder with no flux at all.
If you will wet the target place with proper flux and use thin (1/32-1/64") active core flux solder you should have very good results. If you use plumbers solder :barf: get rid of it. It is the lowest grade solder with tonns of garbage.
For lowest possible temperature and best result use solder paste. For example from Digikey of place like that. It is pretty expencive but very economical and works great. It is a mix of solder powder in the flux. You just apply some paste( feels like toothpaste) and carefully heat the piece up.
 
Dmitry -

I use "no-lead", food-safe solder from McMaster - it is the 4% Silver/rest-tin
solder. More or less identical to StayBrite/Eutectic 15x. For display pieces , may be one can use lead-containing solders, but clearly for kitchen and hunting/fishing type, there can not be any lead.
 
Haven't tried stay bright or other knifesupply soilder, but over the counter the best I've found comes from Car Quest. It comes in a small roll with a small bottle of flux and is listed as silver solder. Never had a problem soldering stainless with it. I'm to the point though that unless it's a split gaurd for a loveless style blade I don't solder, I use JB weld, thanks Terry Premos. I realy like the solderless gaurd, finish the blade, finish the gaurd, glue together and no refinishing. Of course I spend a little more time getting as tight a fit as posible, but to me it's worth it. The JB is mainly a moister seal, the gaurd is a drive on fit. Most times with a big hammer.:D

One trick that I've had decent success with is to cut the thin solder to just long enough to wrap around the joint and bend it as close as I can and then flux the whole thing. Heat from the back side and it flows into the joint. Anouther is to clamp the blade on it's side and lay a piece of solder in the joint and flux and heat from the back side. I use a small piece of sharpend stainless to run around the fillet to make sure all the air bubbles are out and to even up the fillet.

Now I remeber why I hate soldering.:p
 
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