Tooling up for silver soldering

[Dabbler]

I did a lot of soft soldering on brass plate in the 60s during the slot car craze. Very simple and cheap - a 75 watt soldering iron, some paste, and some solder. that's all.... Soft soldered joints where you can't engineer a wide contact area can be fragile. The more stress it takes, the wider the joint has to be.

 

[Boswell]

Chris at Clicksping shows building a few boxes. Looks like he paints on a flux, lays the solder next to the joints and then heats it evenly until the solder wickes into the joints. At leas that is what it looks like to someone that has only done electrical soldering.

 

[francist]

Maybe not applicable to the original question on boxes, but for those interested in a simple setup for smaller items this works well for me.

This is the product that I use, bought from Air Liquide a few years ago.


I stack a corner out of firebricks in any configuration that works for the object — main thing is you want a floor, a back or two sides to bounce the heat, and a roof. I set my piece on little bits of scrap — the smaller the better so as not to rob heat— and into the corner as far as I can but still get at it.



As I alluded to before, I think 1/2” is about as much as you might successfully do in a setup like this. Here’s my test piece of 1/2” bar that I used to see if making a boring bar would be doable. It heated this easily and the braze flowed well. This is just the dummy, so the actual geometry isn’t correct. I was just assessing size capabilities and the simple assembly of firebrick accomplished it fine. I expect a person could be a lot more scientific with the bricks as well, but I’m too impatient for that and just wing it.




Now back to your regular scheduled programming....

-frank

 

[erikmannie]

I disagree. A strong joint is 100% dependent on design. Some of my motorcycles have Brazed slipjoints and they are the strong points in the frame. The beauty of a slipjoint is that if damage ever occurs to a frame tube member they can be unsweated and a tube replaced.
I am a big fan of Castolin,( https://www.castolin.com/),Eutectic rods. A bit pricey but worth every cent. Like most things quality shows in ease of use https://www.castolin.com/technologies?technology=brazing. My favorite is https://www.castolin.com/product/16 which I buy as bare rod for tube work. It can be used as a Brazing rod and after the joint has partially cooled you can overlay the joint as if Bronze welding for extra reinforcement - very versatile. Comes in rods,(coated and uncoated),wire,foils, rings, powder.
Many pneumatic and hydraulic fittings are also made up of Brazed parts. As in most things correct design for the job is paramount.
I think Oxy/Acet has a place in any shop as it is the single most versatile heating process there is.
100% agree on Victor being quality. I use their cutting tips and the difference between Victor and any other brand is extremely noticeable in use.

I should have said, “All other things being equal, a bronze brazed joint is not as strong as a welded or silver brazed joint”. This is due to the relative properties of the materials in question, the least impressive of which is bronze.

Don’t get me wrong, I love bronze. It is just not the first material that I go to when looking for strength.

 

[dbb-the-bruce]

Thanks, lots of good advice and info.

Had some time to do a little research on my own based on the info here. Looks like I can probably do the kind of work I plan with a decent "jewelry" sized torch. Such as "Smith Little torch" with a set of tips.

Brazing vs. soldering - Since all the "silver solder" I've found melts and flows above 450C, I'll be brazing (according to the American Welding Society). Question answered!

I had never given any consideration to solder vs braze - I guess the point is that there are low temp solders (mostly for electric work) and some hobbyists choose to use them because you don't need as much heat. The stuff I'll be making is indented to be jewelry / high craftsmanship quality using higher temp solder.

Small / Jewelry torch kits are affordable and like most things, starting with a good quality kit is worth the expense.

One question- A lot of kits come with empty tanks, as I understand it when you get them filled, your tank will get swapped. So does that mean that the first thing that happens is I trade my shiny empty tank for a vintage tank with a nice patina?

Will probably just go for O/A for the higher temps. Next on the plate is safety research.

 

[dbb-the-bruce]

Maybe not applicable to the original question on boxes, but for those interested in a simple setup for smaller items this works well for me.
Now back to your regular scheduled programming....

-frank

What did you use for a torch/heat?

 

[francist]

Just an ordinary propane torch and tip, nothing fancy. I think the tip is a pencil-flame instead of a broad fluffy one, but it’s not super precision by any stretch. Had it for years and years. The torch will get up enough heat by itself no problem, but without some surplus or something to contain it it goes away too rapidly. That’s where the corner comes in — holds it in the one spot and refracts it back onto the part.

-frank

 

[Ken from ontario]

Thanks, lots of good advice and info.

Had some time to do a little research on my own based on the info here. Looks like I can probably do the kind of work I plan with a decent "jewelry" sized torch. Such as "Smith Little torch" with a set of tips.

Brazing vs. soldering - Since all the "silver solder" I've found melts and flows above 450C, I'll be brazing (according to the American Welding Society). Question answered!

I had never given any consideration to solder vs braze - I guess the point is that there are low temp solders (mostly for electric work) and some hobbyists choose to use them because you don't need as much heat. The stuff I'll be making is indented to be jewelry / high craftsmanship quality using higher temp solder.

Small / Jewelry torch kits are affordable and like most things, starting with a good quality kit is worth the expense.

One question- A lot of kits come with empty tanks, as I understand it when you get them filled, your tank will get swapped. So does that mean that the first thing that happens is I trade my shiny empty tank for a vintage tank with a nice patina?

Will probably just go for O/A for the higher temps. Next on the plate is safety research.

Not too long ago I started a thread asking about O/A torches and smaller "jewelers' set", I ended up buying a Victor torch and two used bottles for Oxygen and Acetylene, I would recommend getting them from your local welding supply store, the new sets you find on Amazon or anywhere else usually are sold empty and you may need to swap them with older ones any way since many LWS do not fill onsite, it would be ideal if they did.

As far as Smith's little torch, I bought one of those , but you should know they are designed for soldering/brazing small pieces like rings, chain links etc. the bigger tips #6 and #7 are most used for brazing, but if the workpiece is too big , it'll act like a heat sink and would take a long time to braze anything that's heavy /thick, it will work but you end up wasting a lot of gas and time to achieve your goal. a regular torch with #00 tip will do the same job in faction of the time.
I use my Smith torch mostly for soldering copper, and sometimes for brazing very small pieces. it will be alright for silver brazing bandsaw blades or stuff like that, but a small MAPP torch will do the same thing.
This of course is my opinion, I'm sure there are more experienced members that will disagree with me but I still think you should do your homework and find out what you'll be using your O/A set for, then get the proper torch, BTW, there are more efficient Jeweler's torch that Mikey mentioned in that thread I posted(Meco Midget), those I couldn't find in Canada but they do sound more capable than Smith's little torch.

 

[dbb-the-bruce]

Not too long ago I started a thread asking about O/A torches and smaller "jewelers' set", I ended up buying a Victor torch and two used bottles for Oxygen and Acetylene, I would recommend getting them from your local welding supply store, the new sets you find on Amazon or anywhere else usually are sold empty and you may need to swap them with older ones any way since many LWS do not fill onsite, it would be ideal if they did.

Yeah, noticing that a lot are sold without tanks. So the first time I buy gas, I pay a bottle deposit that I never get back unless I quit using gas?

I'm going to check out some of the other medium small torches. I really don't need a huge rig - it's not going to get tons of use and storage is at a premium.

I did check Craigs list and Marketplace - but not knowing a lot, I'm a little shy about buying something used.

 

[Ken from ontario]

Yeah, noticing that a lot are sold without tanks. So the first time I buy gas, I pay a bottle deposit that I never get back unless I quit using gas?

If you buy the smaller size/hobby size tanks, (like" M" size acetylene) and for Oxygen (Q or L?) you'll own them up front, you'll get two tanks full of gas and the only time you'll swap them is in when you run out of gas and then you'll only pay for the fill up, these gas bottle in Canada need to be hydro tested every 5 years, I'm not sure about your state.

I'm going to check out some of the other medium small torches. I really don't need a huge rig - it's not going to get tons of use and storage is at a premium.

I did check Craigs list and Marketplace - but not knowing a lot, I'm a little shy about buying something used.

You are right ,you'll be alright with a medium size or even a smaller torch, Bob and Mikey gave me good advice on the size and type of torches in that thread I linked, the medium size Victor torch is what I got and it's plenty for my use . I also have heard good reviews on MECO by other welders from another site.

Check out Facebook market place and CL for a good used set with a well made torch,(Smith, Victor, Harris) and fill/exchange the tanks when they are empty.
Have fun.
Ken.