boiling solder joints

J. Neilson

J. Neilson

Joined
Feb 6, 2001
Messages
3,621
This is one of those "I need to know" questions. I know folks that just spray their solder joints with windex w/ ammonia (like damascus etching), I know folks that sprinkle baking soda over the solder joints (with and without windex) and leave them for awhile and the one I started doing awhile back (thanks to this forum) is boiling the joint in baking soda and water. What the heck is the difference between methods? Which is better in your opinion? And how the heck does the boiling get trapped flux out of a lump of solder? This one's been bugging me for awhile.
:rolleyes: :confused: :rolleyes:
 
Not real sure why boiling works, but I have been boiling mine after some of mine started to rust with only bakeing soda and amonia(Windex).

After boiling I've yet to have one start to rust at the solderjoint. I think it's due to the nature of the acid used for flux. My first were plumbers solder with non-acid flux. I've switched to an acid flux/silver solder combo to solder bronze and stainless.
 
We do boil them simply for the fact that we have run into flux problems too. After Geno solders the guards on he leaves them in a plastic bucket overnight, the next day they are dried off and then come in the kitchen where I boil them in a 4 quart pot for 15 minutes, guards not touching each other, take them out and into the shop to use a airhose to blow under the guard area and repeat the process again. Then they are put into a vise and he uses a heat gun focusing under the guard. I use plain water and it works every time. To answer your question about the flux there are some out there that just don't do as well as others. Cavelady
 
The 4 quart pot is for knives only, I don't think I'd want to be cooking anything in it after that.:D Cavelady
 
Haven't heard of boiling in baking soda water till now. I haven't had a corrosion problem yet but will boil mine from now on because it sounds less messy and less disagreeable than spaying with ammonia.

Thanks for the tip.

Roger
 
Hee hee! Wow I never heard of boiling your kknives after silver soldering, but heck sounds like it may just be the most thorough method around. Hmmm... If I were to think out loud, I would recall that one thing I learned in high-school chemistry (in which I got a D) was that water is THE universal solvent. I have no idea why that little factoid has stuck in my beer-ravaged brain all these years but...

Anyhow, with that in mind I woudl say that a nice heated bath of water would just dissolve anything like flux or whatnot. I'll have to admit that my method has been to sprinkle with baking soda and swish in water, hose off with air, and let dry in a warm spot, like next to the forge (not too hot!).

Guess I'll have to try the boiling thing. Conveniently, in the winter I always have pot of water bubbling away on the woodstove in my shop.
 
Originally posted by Higgy

Guess I'll have to try the boiling thing. Conveniently, in the winter I always have pot of water bubbling away on the woodstove in my shop.
Click to expand...

Make sure to add baking soda to that water. That's what most of us were talking about, although it just got easied off to boiling water.;)
 
SR Johnson has been doing this for many many years, go to his forum on CKD and ask him about it.
 
Originally posted by Mike Hull
Make sure to add baking soda to that water. That's what most of us were talking about, although it just got easied off to boiling water.;)
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Mike, in all due respect, I don't use bakeing soda and am not sure what purpose that's good for. At any rate, what ratio of bakeing soda/water do you use? Cavelady
 
I'm curious also, how some of you folks boil yours. Blade up, down, laying in a pot. Anyone have any concerns about the temp. of the boiling water (approx. 212 degrees) affecting the temper?
 
The baking soda will neutralize acid better, and if nothing else will help slow or stop flash rust from forming. It's good to put some in your dip water for the same reason.
I use a bread pan and put the whole blade in. If the bread pan's too short, I just put it handle down in a pan larger than the burner. I use 4-5 tablespoons of baking soda in the water.
212 degree F., is not enough heat to affect your heat treat. It shouldn't affect the solder joint either, if you were using the right stuff.
 
Hmmm... I like cornbread... maybe I can bake the knife in a pan of cornbread and get the same results? Maybe it will work for cake? If so, what flavor? Vanilla? Chocolate? Carrot?

<grin>
 
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