electrocit

Hello builders,

I was just wondering if anyone knows if I could use jewelry silver solder to add some braze-ons. Why? because I have plenty of silver hard solder and I would rather not buy another type of silver solder if I don't have to. below are quick temps of the solder that I have. I will be using a mapp torch for the braze-ons.

Easy --- 65% Silver

Solidus: 1,240°F (671°C) / Liquidus: 1,325°F (718°C)

Medium --- 70% Silver

Solidus: 1,275°F (691°C) / Liquidus: 1,360°F (738°C)

HARD --- 75% Silver

Solidus: 1,365°F (741°C) / Liquidus: 1,450°F (788°C)

fietsbob

IDK Mapp, in the jewelry classes we used natural gas and a tiny concentrated flame,
when metals had to be melted for casting, that rosebud tip mixing torch used oxygen + the regular gas, combined.


to make complicated pieces we went from high melting point harder to lower melting point easier solders
so the solder joint if the part being attached wont come apart while being fitted..


experiment on scrap materials..


...

unterhausen

do you have any strength data? It seems like it's probably okay, although you might have trouble building a fillet. One way to get around this is to make an effort to increase surface area

Andrew R Stewart 

I agree with the advise to test before real frame work.


But what first struck me about this thread is the term "solder". To me it means a melt temp less then 850*F, and a relatively low strength. Not what I would want on a frame and not what the OP was talking about. It would be interesting to see the brand/model specs of the silver brazing alloys (as I would call them) listed. Andy

electrocit

I'd expect the mapp gas to work since it is a hotter flame. I think I'd just have to be careful with how fast it get up to temperature and then us a light touch at that point. I've made multiple solder joints using just medium and hard by having a light touch once the metal is close to temp.

As for Andrew's comment, Silver Brazing and Silver soldering (as used in Jewelry making) is the same thing. That is why I posted the working temperatures on the "silver solder" they are all above 1200F. There are many post about why there is some confusion about silver solder (high temp)vs silver Bering solder (low temp).

I just don't know what the other elements/metals are in jewelry solder vs the 45% or 56% silver brazing wire/rods. does the binding strength come from the silver or the copper/nickle? I was planning on putting eyelets for a rack on a beater frame, use it for commuting to test the strength

Kontact 

The solders might be the same, but will a MAPP torch get a point on a piece of bicycle tubing hot enough? From what I recall of the jewelry process, it took a fairly long time to get a rather small piece of jewelry hot enough to get the solder to adhere. With the heat sink of a large steel tube, is this going to work?

It would not be fun to find out your brake cable braze on didn't actually fully bond.

electrocit

"The solders might be the same, but will a MAPP torch get a point on a piece of bicycle tubing hot enough? From what I recall of the jewelry process, it took a fairly long time to get a rather small piece of jewelry hot enough to get the solder to adhere. With the heat sink of a large steel tube, is this going to work?"

Mapp is used by many people for braze-ons, some have even used it for framebuilding using lugs.

I did find an MSDS for the Silver solder and it list the other elements/metals in the solder as:

Ingredient __CAS Number __%wt.____Impurities
Copper _____7440-50-8____19-95 ___none known
Silver_______7440-22-4____1-55____ none known
Zinc ________7440-66-6____2-44____none known
Nickel ______7440-02-0____1-24 ____none known

Andrew R Stewart 

There's the answer. Try it. As someone said for silver you want a lot of surface area in play. Hourglass shaped bosses on a stay are fine w/ 56% silver filler but doughnut eyes on a drop out and i'll use brass. Andy

elcraft

As a professional jeweler, we call it silver "solder" as "brazing" material implies it is made from brass. Technically, "Silver Bearing Solder" is a low temperature solder that contains silver in the alloy. I believe they are grouped with materials known as "Eutectic Solders" (too off topic to actually go into here). As for applying enough heat, more depends on the Torch configuration than just which fuel gas is used. I routinely use low pressure, common natural gas ( w/ Oxygen) to melt and weld Iridium/Platinum alloys with at about 1800 degrees F. Common natural gas is rarely more than one psi! The torch that I use has a "rosebud" cluster of multiple offices on the Brass torch tip. I can melt an ounce of sterling silver at 1640 degrees F in under 2 minutes. This torch however, wouldn't have as broad a flame as one would want to heat up lugs or cycle tubing sufficiently quickly to avoid the flux deteriorating. There are plumber's type torches, designed to burn either Propane or MAPP without the aid of compressed oxygen. The torch design usues multiple orifices arranged into a spiraling "Venturi" to ramp up the heat. As for their effectiveness for frame building, I don't have any hands on experience to say categorically that they are adequate to the task. That being said, I'd be willing to wager that they can handle the job.

unterhausen

the problem with MAPP is that to get it to heat sufficiently, you have to concentrate the heat. It's really difficult to avoid overheating. Doing it on a dropout just sounds like it will never get to temp, unless you and a couple of friends each have a torch, and then good luck with the heat control.

I'm going to go ahead and say that your experiment with rack eyelets is going to fail. They break off with higher strength filler metals. Your only hope is to make as much surface area in the joint as possible.

Brazing is the common terminology for high temperature silver filler metals even though there might not be bronze in the filler. I'm sure the AWS defines it better than I feel like doing.

electrocit

That is industry dependent. In jewelry making the common terminology for high temperature silver is solder and soldering. Brazing in jewelry making is only for brass. This is fairly well known and was standard across most industries until the invention of Silver Bering Solder for electronics.

Andrew R Stewart 

And we're a frame building community here, not jewelry making. We're both right and wrong. But here in the framebuilding world brazing IS the term for the 3rd party joining we do (be it with silver, brass or bronze based fillers with nickel sometimes too).


This is like the steering geometry terms that are different between motorcycle or automotive world and bike ones. Andy

unterhausen

Back to the American Welding society. According to their definition, which is widely accepted, the difference between brazing and soldering is the temperature. Below 842F is soldering, above that is brazing. However, that temperature is oddly specific. Maybe it delineates when there is enough zinc and copper that jewelry makers consider there to be bronze involved, I dunno.

fietsbob

NB silver solders wont fill big gaps... well known; stainless lugs have to be close tolerance fits.

jamescycles

I have used a MAPP torch to do braze-ons, such as brake bosses and cable guides with a MAPP torch, using 55 percent jewelers silver and 45%, without any issues. I do not know how strong your solder is, but I assume it is more than strong enough, given the high amount of silver, a Google search, did not show any technical info.

electrocit

Great to hear that. I do plan to file down one edge of my eyelets to have a bit more surface contact with the drop outs. I know how tight the seam needs to be for Silver Solder so I'm not to worried about that part. Never done brazing on steel so this will be a fun project for me since all of my "brazing" experience has been with silver solder (high temp stuff) on sliver, brass and copper. I've only done MIG welding working with steel and TIG working with aluminium, but that was ages ago when I was in collage for various art projects. Once I have some time to do the testing I'll update the post with some results.