# Which torch for silver soldering?



## AllThumbs

Here are 3. Any advice?


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## GailInNM

Which torch? The classic answer of "it depends".
I use a MAPP torch like torch #3 in your selection list for 90 percent of my silver soldering. It is what I am using for band saw blade brazing in the thread at:
http://www.homemodelenginemachinist.com/index.php?topic=305.msg15401#msg15401
It is suitable for assemblies of brass of up to several ounces in weight.
The main thing I don't like about this type of torch is that it is either on or off as there is no gas flow control knob on it. The only way you can adjust the heat applied is by changing the torch distance from the work. 

I don't like the downward pointing torch, #2, as I normally want to heat from underneath the part with a small length of silver solder on top of the joint for most small parts. If the flame is applied to the silver solder, the silver solder will melt before the metal is hot enough to for it to flow. 

For very small parts I often use a pencil type propane torch like #2 but with the upward pointing nozzle. This is for parts like .014 wall brass tubing to small fittings. There the MAPP torch provides too much heat too fast, although it can be used. 

I also have a torch like shown in #1. I have it connected to a BBQ type propane tank. Mostly it is used for heating my coffee can foundry furnace for small castings, but I also use it as a preheat source for larger silver soldered items such a small copper boilers in the 2 inch diameter x 8 inch long range. There I set the boiler shell up on insulating firebrick and mount the torch to apply a generalized flame to help keep everything hot. Then I use the MAPP torch to move on the boiler to bring the local areas up to temperature for soldering in end caps and bushings. 

So as I said. It depends. If I only had one torch for silver soldering, I would chose #3.

Gail in NM, USA


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## Lew Hartswick

All 3 were too big for the only silver soldering I've had to do in a loooooong time. 
Was trying to make some special hinges by soldering peices of rod with a hole in center to a flat 
peice of stee, keeping the two peices aligned with the required space between. 
Ended up having a friend do it with a Oxy-Acetylene and a very small tip. 
 SO as is always the case: "It all depends". 
  ...lew...


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## AKViking

Although it is more expensive at $99, I like the EZ Torch (http://www.ottofrei.com). It uses standard disposable propane bottles and has an air adjustment and several sized tips. It is very simple in design and replacement parts are readily available from Otto Frei.

Since it takes the small propane bottles (you can get an adapter for the 20lb bottles) it is legal in countries where large bottles for residential use are prohibited, apartment buildings, etc. It is also hand on islands in Alaska where we only have one place to fill our acetylene and oxygen !


I have a larger acetylene jeweler's torch as well as a oxy/propane mini-jeweler's torch, but I find myself reaching for the EZ Torch most of the time. It has plenty of heat for most jewelry/model making applications. My two cents worth as a jeweler who has started dabbling in a little model making.


Chris in Ketchikan, AK


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## AKViking

Correction: $89 for the small propane bottle model, $99 for the large propane tank.


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## Bogstandard

It is very difficult to make a decision on your behalf because it looks like the part of the world you come from, you have very little choice.

There are no hard and fast rules for what size torch you require, because it all depends on the size of the job.

I in fact use four different sized ones, ranging from a micro torch, a cooks blowtorch, a plumbers general purpose (the size you are looking at with the fixed on bottle) to a beast of a pipe running from a propane tank. I have attached a pic to show you what I mean. The two middle sized ones are the most used.
One thing not recommended is oxy/acet. It tends to put too much heat in too quickly, plus on very small nozzles it can be difficult to see if you have either a carburising or oxygenating flame, which can adversely affect the joint.

Maybe these two topics might help.
http://www.homemodelenginemachinist.com/index.php?topic=265.0

http://www.homemodelenginemachinist.com/index.php?topic=917.0

There is also a piece about complex silver soldering in my post here, about half way down the page.
http://www.homemodelenginemachinist.com/index.php?topic=1500.90

John


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## rangerssteamtoys

Depends on what your soldering and how big it is. I use a little ronson butane torch, its been dropped a few times and the ceramic tip is falling apart. With this I can solder alot of stuff, and If I need more heat I use an alcohol burner to heat the metal and then solder it with the torch.

Hopes this helps. 

As for the pics of torches, I would go wih the last one. I like big fire


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## Loose nut

I generally use oxy-acetylene, tips are changed to match the work but it is very easy to "burn" the work because the heat is to concentrated, propane puts out more BTU's but the flame is more diffuse so it can heat a larger area evenly but difficult to do fine work. If you were doing a largish boiler then a Severt type torch would be best (the old timers used gasoline torches, very scary) but for smaller work like a small engine part then any hand propane torch is OK provided it puts out enough heat to do the job. Use the large tank adapter, it is a lot cheaper to by the propane that way and it makes the torch easier to manage than trying to hold a bottle.


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## GailInNM

As mentioned by everyone, a lot depends on the size of the parts you are going to silver solder. In the photos below is an example of one of my current projects that will be silver soldered in a few days. I will use a MAPP gas torch like your #3 to do the silver soldering.

The first photo is of the parts that will go into the assembly. It is the standard with crosshead guide for a 1/2 inch bore and stroke engine. There are 7 parts made of brass 260 and 360. The base and top flange are 1/8 inch thick. The sheet metal parts are 1/6 inch thick and the turned trunk has .086 inch thick wall.

The second photo shows the parts test fitted on the silver soldering jig. All the fitting and filing have been done at this point. Next the parts will be removed and all scratches sanded out and any other detailing done. After that they will be cleaned, first with alcohol and then a brief acid dip and rinse. Then all solder areas will be fluxed and the parts reassembled in the soldering jig. Small lengths of 3/64 diameter 56 percent silver solder will be placed along the joints and the whole mess heated with the torch until the solder flows. There will be 14 solder joints done at once.


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## zeusrekning

I just tried melting some 1/16" dia silver solder with my propane torch with no luck. Whats up? Is this size too big for what most of us are doing???
Tim


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## GailInNM

Tim,
Do you know what the silver content of the silver solder you have is? Some of the low silver content solders with 10 to 20 percent silver melt at much higher temperatures. Most of the model makers I know use solder with either 45 or 56 percent silver. More expensive, but it will flow into close fitting assemblies and melts at lower temperatures. I have silver soldered a lot with 1/16 wire with propane with out difficulty using both 45 and 56 percent silver solder. 
Gail in NM, USA


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## zeusrekning

I think the label said silver-flo 45.
Tim


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## kf2qd

I use torch #2. For smaller parts it works great with propane. For some bigger parts I used MAPP gas. GOt mine for $15 a couple years ago right after Christmas. Really like it. Large Hot flame that doesn't extend much past teh torch tip. Easy to control and the torch swivels around the pipe running out of the valve. Also works nice for lighting the outdoor wood burner...


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## AllThumbs

zeusrekning  said:
			
		

> I just tried melting some 1/16" dia silver solder with my propane torch with no luck. Whats up? Is this size too big for what most of us are doing???
> Tim



What was the solder sitting on? If a vice of something perhaps it's a good heatsink.

E


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## GailInNM

Silver-Flo 45 should flow easily with a propane torch on small parts. It is a Cd free solder so it's temperature is a little higher than the older 45 percent silver solders, but not by much. Only about 30 or 40 degrees F from the Cd free solder that I am using. 

Try clamping a strip of about 1/2 inch wide 1/32 thick or so strip of brass in a vice with a flat side up and about an inch hanging out. Put a little flux near the end and then put a 1/16 or 1/8 inch long piece of your solder in the flux. Heat from the bottom with your torch. Shortly after the flux melts and turns clear the solder should flow out on the brass. The flux is important not only for the cleaning of the metal but for the initial heat transfer to the solder. 

Gail


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## PTsideshow

To go along with the discussion of torches here is the grandaddy of information on line for silver brazing with more info than one can use.
From FAQ's to material data safety sheets. From the company that makes most of the silver brazing(solder).
http://www.lucasmilhaupt.com/htmdocs/brazing_support/everything_about_brazing/what_brazing_about.html

The EZ torch as mentioned by AKViking is a pretty good set up for using the different silver solders temperatures for attaching parts. It is also called and sold as the Shark torch. It is made by Otto Frei http://www.ottofrei.com/


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## PTsideshow

Along with the old standby for silver brazing work on heating and air conditioning. Along with general plumbing work. The prest-o-light torch, which was bought out by the turbo torch people. Which is the old standard for silver smithing the air/acetylene torch. When the patent lapsed years ago, A number of other companies quickly put it into production. So today whether it is a prest-o-lite brand, goss, uniweld etc the parts are inter changeable. 
The only problem is still the original one with the mission impossible wrench that disappears after the first time you use it!
The B tank (bus) and the MC tank (motorcycle)reason for the angle on the valve. The MC is also called Miniature cylinder in parts of the US.
Here is a site that has most of the brands of torches and styles and a pretty good resource for checking out the differences.
http://www.kingsleynorth.com/skshop/search_results2.php?action=search&keys=&catID=214&Submit=+Search+
They also have a lot of other tools you never knew you needed.


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## PTsideshow

Another good general purpose torch for smaller welds or brazing is the Smith's little torch. An oxy/fuel torch that works up to 16 ga sheet goods from steel to gold. The only stipulation they give is if using the smallest two tips you should use acetylene or hydrogen as the fuel gas for the higher temps generated.
Gentec is another company from Europe that has a version of this torch.


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## PTsideshow

A air/propane torch that will work for certain jobs in the shop is the Gentec quick change tip torch which is copy of turbo torches quick change tip. From some silver silver brazing,melting lead, pewter, to removing tile and small dia. bending and forging it works great.

And of course can we forget Benz O Matic's entry in to the OH my! does this thing blow through the tanks, in use. It does work for small stuff and it is light enough to tie to your belt, or take it in tight places with you with out to much strain or in to an office environment. Where they tend to frown on industrial equipment.
If I remember correctly the MC sized tank is about 18 of the Benz O Matic tanks.

Here is Benz O Matics site full of useful info.http://bernzomatic.com/bernzomatic/consumer/jhtml/index.jhtml?_requestid=1244


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## PTsideshow

In case you missed it, MAPP gas is no longer being offered for sale. Here is the announcement from the producer
http://www.worthingtoncylinders.com/documents/map_pro_introduce_announce_021908.pdf
It is a PDF download.
They have moved up another of the gases used under other names to reduced the inventory of slightly different properties. With a greener gas in keeping with the reduction of carbon foot prints.

If you go to the main site they have their price increase announcements listed.
http://www.worthingtoncylinders.com/


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## Loose nut

If you want to learn about soldering and brazing of just about anything then a good book is "Soldering and Brazing " by Tubal Cain, it's one of the workshop series that Model Engineer puts out ( or used to. I don't know who has them now).


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