Tooling up for silver soldering

[John_Dennis]

One of the things you have to watch when soldering is to be sure that the parts are not force fitted. In some cases if the metal is under tension when the solder is applied it can cause a "Liquid Metal Fracture". I read about this on this forum years ago and have had several welders and machinist confirm that it is a known problem.

I have a HHO hydrogen welder that I use to solder stainless wire for orthodontic appliances. It is extremely hot, much hotter than oxy/acetylene. The reason that I use it is that I can not have compressed gas in my building. It is a very expensive torch compared to an oxy acetylene rig.

 

[Dabbler]

@John_Dennis Offshore HHO rigs can be had for a small outlay. I know their quality isn't as good as commercial ones, but for a hobbyist brazing a few carbides per year it might be the best choice.

 

[John_Dennis]

@John_Dennis Offshore HHO rigs can be had for a small outlay. I know their quality isn't as good as commercial ones, but for a hobbyist brazing a few carbides per year it might be the best choice.

The import torches may work well, I havent tried any of them. One thing to consider though is that the electrolyte in the tank is corrosive so the parts are going to be wearing out even when not in use.

 

[Dabbler]

@John_Dennis the user manual usually recommends draining the tank into a suitable container when not in use.

 

[John_Dennis]

That electrolyte solution is nasty stuff, most people use a turkey baster to empty the tank and then rinse it out. It is a lot of work for occasional use. I use a TurboBraze, it would not work well on large items. I think I could braze a carbide onto a .25 bar but anything bigger would be difficult.

 

[ericc]

I think you could get away with one of those little butane cylinder torches with an oxygen concentrator in a restricted building. This is a miniscule amount of compressed gas. It is comparable to the amount of compressed gas in a can of whipped cream, and at a lower pressure. By the way, I carry a pretty nasty load of compressed gas all the time, and it is flammable. I rarely have an accident, but it can cause quite a commotion in an elevator.

 

[ACHiPo]

that is a unit that creates hydrogen gas and oxygen from distilled water and an electric current. If you go to sites such as banggood.com and search on hho, you can see pictures of the unit they sell. There are a few videos on youtube on using an HHO torch, which should be instructive.

The nice thing about HHO is that you get the control and intensity of a gas torch, without the problems of bottled gases.

Here I find myself down another rabbit hole...

I silver brazed a lugged bike frame (Reynolds 531 double-butted chrome moly tubing and Italian lugs) with OxyAcetylene many (like 40) years ago in my 'yout'. Now I find myself wanting to build a model engine requiring silver brazing (maybe soldering would be ok?) without an OA rig and without an inclination to have one more big item in my shop that I only use periodically, so I'm considering alternatives.

1. Mini OA set. About $300 for a Victor or Harris set up. How long do the tanks last?
2. HOH set. Never knew about this before last night (thanks Dabbler!)--turns out it was the first gas welding/brazing heat source. Uses DI water and KOH and electricity to generate hydrogen and oxygen. About the same price as a mini OA set. No nasty carbon from acetylene. A little worried about the KOH electrolyte though? Any idea about the cost of consumables? The KOH doesn't seem too expensive, but I don't know how much is used? The DI water is easy. Are there consumable electrodes?

Acrylic Flame Polisher Oxygen-hydrogen Generator Water Welder Polishing Machine
95L flame polishing machine HHO welder from U.S. Solid

ussolid.com
3. MAP gas. I already have a Bernzomatic TS4000 turbo torch and MAP/Pro gas.
https://www.lowes.com/pd/BernzOmati...mqQVFH889XbzbhT61RoaAqGGEALw_wcB&gclsrc=aw.ds

Mebbe I should just pick up some Harris Safety-silv and Stay-silv and give it a go?

Harris Safety-Silv 56 Brazing Kit 56KPOP
Buy Harris Safety-Silv 56 Brazing Kit 56KPOP today at the lowest prices anywhere. Fast, free shipping. Get yours now!

www.harrisweldingsupplies.com

Seems like with a fire brick "furnace" the torch might produce enough energy to work for hard silver brazing? By the way, who knew there were a bunch of different kinds of firebrick? Lightweight is much less conductive that hard brick, but fragile. Yet another rabbit hole.

Curiouser and curiouser!

 

[ACHiPo]

I have posted this before so apologies if you have seen it:

View attachment 317474
You can get these on CL for less than $200

Robert

I've heard these operate (they are used for COPD patients) and it sounds like they pulse. Do they deliver a constant pressure of O2?

 

[Mitch Alsup]

The hospital units (COPD) work by using Pressure Swing Adsorbers; which run a 4 cycle (pulsing) process to take 19% O2 from the air and create 95%+ O2 at rates acceptable to a person with partially functioning lungs.

I wonder (doubt) if they have enough volume to run an oxy-acetelene torch at high enough heat rates.

The DI water separator just uses electricity to decompose water into H2 and O2. The more electricity, the more H2 and O2.

 

[Larry$]

I don't have a Oxy Acet set any more and prefer that over propane or Mapp. I recently silver soldered carbide to steel with Mapp. Worked but took a long time to get everything hot enough. I was using some fire bricks as a reflector/heat trap. I was surprised it worked, especially since the grade of carbide wasn't ideal for brazing or silver solder.