Beaten by Silver Solder - Again

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logem

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Does anyone have repeatably good results on soldering? S30V blade to 416SS Guard.

Man, I hate soldering guards for the following reasons:

1) I can't ever get the solder to flow at the low temperature that it should . . . no matter how clean my parts are.
2) I always scorch the nice finish on my blade and guard, and have to come back to try to clean them up again.
3) I'm afraid that I'm compromising my heat treat, although I take multiple precautions such as wrapping the blade in a wet cloth, using heat blocker, etc.
4) The bleeding silver solder (since I use too much, because I can't get it flow easily) has to be cleaned from the blade and guard faces using a brass scraper. Even then, I further compromise the original finish.
5) The flux tends to etch the blade finish, requiring even more finishing to make the blade back to original condition. (Yes, I rinse in a base fluid to neutralize the acid)

I think it's time for JB weld or similar metal epoxies. Good thing I'm not a welder.

Mike L.
 
What is your heat source and how much clearance between guard and blade? Also what type of solder are you using?
 
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As stated before: I mostly try to silver solder 416SS guards (pinned) to S30V or CPM154. Currently, I'm struggling with S30V.

The solder is Radnor Safety-Silv 56. The brazing flux is Stay-Silv. I'm using MAPP gas for the heat source. I try slow heating and then concentrated heating, but neither work.

I'm aware that solder flows towards heat, so I try to keep the majority of the heat on the opposite side of where I'm placing the solder. I know to evenly heat the whole guard though. I want to "coerce" the solder to opposite side of the guard with just a little bit more heat.

Since I don't have access to a mill, my guard slots are hand filed, and probably have 0.005" to .010" clearance in some locations . . . yet some spots are "size-to-size".

Mike L.
LoGiudice Custom Knives
 
You don't want to be size to size anywhere,the solder should surround the blade.(.003 to .005 is good) Make sure it's clean and brush it with flux. I like to put a small piece of solder on each side, apply heat primarily to the guard. Keep the heat moving all around the guard don't hold in one spot. When those little pieces melt it's time to remove the torch and lay down a bead.The smaller your clearance the less solder you will need to make a good joint. Be patient don't rush it. I use stabrite solder and flux .040 diameter anything thicker will require more time. Hope this helps.
 
That solder is hard solder, and using that much heat can compromise your heat treat.
Use 4% silver solder, Stay Clean flux, and a propane torch. It's much easier.
 
Yes , use soft solder ! .003" is best for capillary action for the solder to flow , and best for strength.
 
Get rid of the MAPP torch for soldering purposes, it is too hot and will lead you to over heat your joints. A propane torch or even one of the mini butane torches is a better bet. I've heard some guys say they have soldered guards with a heat gun.
I have a knife I want to solder the guard on but I'm leaning more towards JB weld. Even if I do it as right as I am able there is still a big mess left to clean up, I may have compromised the temper, and any flux trapped in the joint (it happens) can begin attacking the blade years down the road.
Forgot why I wanted to solder that guard...:confused:
 
Steve Johnson uses a heat gun on low temp solder in his subhilt dvd.
 
logem said:
Does anyone have repeatably good results on soldering? S30V blade to 416SS Guard.

Man, I hate soldering guards for the following reasons:

1) ... etc.

Mike L.
Click to expand...

My results are repeatable, but they're crappy repeatable. I'm with ya on the frustration.


Quote: "Steve Johnson uses a heat gun on low temp solder in his subhilt dvd."

He can NOT be using silver solder with heat gun!?!?!?!? Can he??? What would be so wrong to use a low temp soft solder (non silver, not lead) rather than JB Weld? Is JB Weld sooooooo strong? Will JB Weld last as long as a soft soldered joint?

Frunstrated and confused minds want to know,

- Paul Meske, Wisconsin
 
I read that solder doesn't stick as well to highly polished surfaces- since then I stopped buffing the face of the guard before assembly, leaving it at 1500 grit instead. Solder seems to flow a bit better. Tooth-brushing the guard/blade with Dawn or other concentrated detergent works better than acetone to clean before assembly, acetone can leave a bit of residue.

Also, I've had to just get better at solder cleanup. Making tape is your friend, and so is a sharp solder chisel with two sizes of oval face. A dremel or rotary tool with a buff, cut to taper outward can buff the guard face nicely. And I have a single bevel carpenter-chisel shaped micarta stick, that I can use to sand the guard face after soldering, or drag lines back onto the ricasso to erase cleanup marks from a sanded finish.

A trick I use if a solder joint is proving difficult, is to dip the end of my small solder chisel into liquid flux, then use it to draw the solder around the joint.

Even so, I screwed one up a bit the other day. Guess I wasn't holding my mouth right.
 
Soft (lead) solder is fine for carbon steel, but it won't work on stainless.
Any solder joint should be fresh, clean metal.
You can use a soft lead pencil and draw lines where you don't want your solder to go. Unless you use too much solder, it won't jump the line.
 
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I believe Stay-Brite solder is the easiest to use for this purpose. I clean the inside of the guard and the knife where the guard fits then apply the zinc chloride solution to each part separately and allow to dry. This will leave a thin coat zinc chloride only on the parts to be soldered. I also paint yellow ochre on the parts that I don't want the solder to stick to. I have soldered 4 guards but each is improving and it is taking less time to clean up afterwards. On the last one I flattened the solder so it touched the joint better and applied it to the front of the guard. The yellow ochre helped keep the solder from sticking to the blade or guard and the heat drew the beads of solder into the joint. If you can get your hands on an industrial 100+ watt soldering gun it might provide enough heat for the Stay-Brite solder depending on the size of your guard.
 
Properly "soft " solder refers to melting temperature .Misuse of terms has caused a lot of confusion. Solder should be used for low temperature melting alloys [below about 700 F ] Above that they should be a "braze" rather than "hard solder" .
If you are using stainless steel then a soft silver solder must be used with a flux made for stainless steel .They melt at about 400 F and contain 4-5 % silver with tin.
Polishing is not good for soldering or with adhesives.
 
Bill DeShivs,

Thanks for pointing out that I grabbed my hard solder/brazing metal and flux, rather than my soft solder and flux. I don't even remember why I purchased the brazing metal. Anyway, that was a lack of thinking on my part.

For those of you looking for the specific products to use for a soft solder joint, here is what you need:

Stay-Brite solder made by Harris (96% tin, 4% silver, 430F melting point, recommended clearance of .002/.005 [per side when using for a slotted guard])

Stay-Clean flux made by Harris (zinc chloride paste or liquid flux, active temperature up to 700F, Used for soldering virtually all metals, except aluminum, magnesium or titanium)

You should be able to purchase these at a welding supply or A/C supply shop.

Thanks again,

Mike L.
 
Hi guys,
I just did this and my joints turned out fine. first I clean it really well, it's 100 percent isopropyl alcohol. then I applied the flux using a q-tip very sparingly. Next I heated the steel first using a microsoft torch and let the steel get to temperature first. I went very slowly! I had to quarter inch pieces of solder laying down on each joint. when the solder started to melt I took the torch away and use the brass chisel to push solder that wasn't flowing into the joints already into the joint. then I used a different brass chisel to clean up the solder around the joint. This cleaned up any high spots and made sanding after it cooled a breeze.
it is a nice looking going now. I use 220 grit sandpaper. I failed miserably my first few times doing this, so I practiced with some old brass in some steel that I cleaned up. I I think a hypodermic needle would be the way to apply the flux to joint, to minimize the amount of flux getting outside of the joint area.
don't give up if you're having trouble with this you can do it, just go slow and take your time. have everything you need ready to be able to grab onto quickly and work clean. its only took me about 10 minutes total time...
good luck!
 
Knifemadman,
Welcome to Shop Talk, and Bladeforums. If you glance at the date line, you will see that this is a two year old thread. I appreciate your input, but try and avoid answereing two year old questions :)
I am closing this thread.
 
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