Gas Torches for Brazing Copper

[catceefer]

I currently use one of these propane torches for brazing copper, generally selecting the largest of the three sizes. In the past, most of my work has been quite small and it has coped well enough. However, now that I am working on a dragon with thicker (0.5mm) copper and larger pieces, it cannot get the work hot enough to braze.

 

Stupid question: do I just need a larger nozzle, perhaps the type used for weed burning, or do I need to invest in something like an oxy-propane set up? I did consider MAPP as an alternative, but I get the impression that the gas cannisters do not last that long.

 

Regards,

 

James.

[DSW]

An air acetylene torch gets much hotter than typical propane torches. An air acetylene torch is what most plumbing and HVAC contractors use to solder and braze piping. Goss and Turbo torch are usually the big names in Air Acetylene, though they also make dedicated air propane torches as well. Oxy fuel would be the next step up. Oxy propane can be used for brazing and soldering and Oxy Acetylene can do brazing, soldering and welding.

 

 

http://victortechnologies.com/turbotorch/products/prodList.html?brand=TTT&W2Code=TTT200200&W3Code=TTT301200&W4Code=TTT400400&W5Code=&W6Code=

 

My small air acetylene torch will solder up to 2" copper pipe fittings and braze 3/8" to 1/2" fittings with no issues. I've done over 4" copper / brass pipe fittings with the big rose bud on my Oxy Acetylene rig.

[John McPherson]

Batts of ceramic wool insulation, or soft firebricks strategically placed can (1) contain and reflect the flame, (2) slow radiation heat loss, (3) help reduce the convective heat loss, and (4) allow you to braze thicker pieces with the same torch.

 

A plumbers propane torch in the open air will barely heat a small section of a steel rod to bright red. The same torch in a bean can forge will melt steel.

[catceefer]

Thank you for your replies.

 

DSW: I had not realised that you could get straight air-acetylene torches. I shall have a look to see what is available over here in England.

 

John: I did try stuffing the work with refractory material and working within firebricks. It did help, but not sufficiently to effect a decent joint. However, as I progress with the project, I will be forced more and more to be working with pieces where filling them will not be viable, so I shall have to look for an alternative torch.

 

Regards,

 

James.

[DSW]

I didn't realize you were in the UK. It helps to note that in your profile so we know where you are from all the time.

 

 

I'd assume they have them over there even if the fittings are different. I'd guess plumbers and so on use them like we use them here. You probably have to look at welding supply houses or trade shops that cater to "pro's" vs home centers.

 

I came across this pict of my little "B" sized air acet rig that I took when I picked it up off Craigslist. I think I paid $100  for it complete from a plumber who was retiring and unloading a lot of his duplicate stuff. The tips can be changed similar to what you showed to change heat based on what size material you are working with. I picked up my 2nd rig almost new from someone who was moving overseas and had used it for art brazing and jewelry. That one was even cheaper. They had the cylinder listed  on CL and thru in the torch and reg for free.

 

I also have a air propane rig that is very similar that I picked up at a flea market cheap. Unfortunately I'd already sold off all the propane tips that I'd acquired in a lot I bought at an auction because they came with a reg and acetylene tips I wanted. I think I paid something stupid like $5 for the propane rig so I couldn't pass it up.

 

[John B]

BOC can supply air aspirated acetylene units complete with ignition system,

[ianinsa]

just a dumb question, why are you braising 0.5mm and not soldering? there are some bril German solders?

 

Ian

[catceefer]

just a dumb question, why are you braising 0.5mm and not soldering? there are some bril German solders?

 

Ian

Ian,

 

Perfectly reasonable question. There are two main reasons:

 

1) I feel that the way that a brazed joint weathers looks far better than a soldered joint, and many of the joints will be visible.

 

2) When I have soldered large items before, and then added more detail pieces, I have had problems with the first joints failing under the heat needed for the additions. Although this can still happen with brazing, I have had far fewer problems. This particular piece will have several small pieces adding on and I have visions of it disintegrating if I use solder.

 

However, these German solders of which you speak may be different. Do you have any details of them at all?

 

Thank you.

 

James.

[ianinsa]

James, I have done some large copper projects in the past ie. copper rooves  ans the associated bulkheads on pallaces  in the UAE. I bought solder in Abu Dhabi it was from Germany and it had a higher than normal melting point, so a standard propane torch struggeled with it, mapp gas worked well. On multiple joins I stuck a peice of aluminium behind to act as a heat sink .

 

Ian

[Countryforge]

 I do a lot of brazing of copper and  brass I us a tig torch very fine, very accurate and very fast it can be adjusted for even thin copper, just a thought

[catceefer]

Ian,

 

Thank you for the suggestions. I have been looking for German solders, but have been unable to find anything much (Google is also insistant that I meant "German soldiers" and keeps giving me pictures of Stormtroopers".)

 

Countryforge,

 

A friend has a TIG welder. I may take some bits of copper up to his workshop and see whether I can have a play.

 

Regards,

 

James.

[Countryforge]

Try a product called silphos great stuff

[catceefer]

Well, they say better born lucky than rich. After due consideration of the general suggestions here, I mentioned to friend that I had finally decided to buy an oxy/propane kit. It turns out that he has an unwanted, unused oxy/acetylene kit that I can have as it is in the way. It comes with a wide selection of nozzles and an angled brazing head. It needs a new fuel regulator, so I will get one for propane.

 

Am I right in thinking that the fuel hose should be changed for a different material if it is being used with propane?

 

Countryforge: I think that SilPhos is what I currently use - a copper to copper, fluxless braze.

 

Regards,

 

James.

[John B]

Hi James, some fuel hoses are ok to use with acetelyne or propane mainly the more modern ones, so check what you have on your unit.

 

With regard to the soldering/brazing debate, I believe that the current International Convention is that brazed joints are made above the melting point of aluminium (610 degC) and are also known as hard soldering, silver soldering or brazing, below that temperature, you are soft soldering,

 

I think Ian is using (German)  silver solder which comes in different qualities/melting temperatures for different applications

 

A brazed joint is identified by the temperature of the filler metal, not the material being used as the medium.

 

Which then poses the question if you tig weld using parent copper/brass to themselfs is it technically welding, or brazing?

 

Brazing is a capillary action wheras welding is a unification process (Others have more knowledge on this terminology and process)

 

If you are having trouble with bits falling off or coming loose you may have a design flaw in the joint design, or using the wrong jointing style, consider overlaps and recesses or the use of dovetails or tongues.

 

A brazed joint is strongest when in a shear or torsion situation, and at its weakest when in tension like a butt joint, surface area is important.

 

Properly made silver soldered joint strengths are well above the strength of annealed copper or brass.

 

Wandered a bit from the question, but the information may be useful to someone.

[DSW]

Which then poses the question if you tig weld using parent copper/brass to themselfs is it technically welding, or brazing?

 

Brazing is a capillary action wheras welding is a unification process (Others have more knowledge on this terminology and process)

 

 

The basic generic explanation for brazing vs welding I've always been taught is that if you are melting the base material, you are welding, where as brazing/soldering the base material remains intact, but the filler is molten. Because the base material melts in a weld, the filler and base material mix and change the composition of the weld itself. With soldering/brazing the base material alloy at the joint location remains the same. The braze material or solder just bonds to the surface vs mixing with the base material.

 

When looking at tig welding / tig brazing that distinction would differentiate the two. If you are melting the base, then you are welding, if not, you are brazing. With copper and brass alloys where the melting temps of both the filler and the base material begin to come quite close to each, it's often a very fine line between one and the other.

[DSW]

Well, they say better born lucky than rich. After due consideration of the general suggestions here, I mentioned to friend that I had finally decided to buy an oxy/propane kit. It turns out that he has an unwanted, unused oxy/acetylene kit that I can have as it is in the way. It comes with a wide selection of nozzles and an angled brazing head. It needs a new fuel regulator, so I will get one for propane.

 

Am I right in thinking that the fuel hose should be changed for a different material if it is being used with propane?

 

 

 

Hoses designed to work strictly with Acetylene are type R. Hoses used for other fuel gasses including acetylene are type T. In some cases the outside sheath of the hose is clearly marked as to the type of hose used, In other cases it's not. Typically either older hoses, or cheaper off brand hoses have a tendency to be type R more often than more expensive name brand sets. However generally more and more companies are simply just using type T on all their kits.

 

 

Note that your tips will need to possibly be changed as well. The flame cone on an oxy propane torch is different than that of an oxy acetylene one. Some torch tips cross over with no issues, but you may need to change sizes vs what you'd use with acetylene. For example my air acetylene tips are much smaller and completely different than my air propane torch by the same company. I don't use oxy propane to heat with currently, so I don't have the conversion chart for the "welding" tips. My oxy propane cutting torch however uses a completely different tip than the one on my Oxy acetylene cutting torch. There is a completely different hole pattern on the propane tip to deal with the change in flame configuration and the different flame cone. I believe an Oxy propane rose bud is also different, but I haven't converted that rig over from Acetylene yet because I haven't had a large heating job that has required that conversion yet.

 

I'd pull up a chart from the manufacturer of whatever torch set you get. Most tips are clearly stamped with the tip number and you can check the conversion charts to see what tips will cross over based on the size material you are working with. I had to do that with my Smith cutting torch when I converted it to propane, and I'll end up doing the same thing when I end up converting over the Victor handle for a propane rosebud.

[catceefer]

Thank you for the advice regarding hoses and tips. I should be collecting the set in a week or two, so will be able to check the type of hose and the tips then. Thinking about it, though, I imagine that I could just use the regulator and hose from my current propane set.

 

Regards,

 

James.

[catceefer]

After playing about with the torch that I was given and looking into it a little more, I am having second thoughts about an oxy-propane set up for a number of reasons and am looking at MAPP torches in more depth after all.

 

The Victor torches seem to be more favourably viewed and three models are readily available here: the STK-11, TX-504 and the STK-9. The trouble is that I cannot work out from the details on the Victor site what the differences are between the models and whether any is really suitable for brazing.

 

Does anyone have any experience of these torches and able to advise?

 

Thank you, yet again.

 

James.

[DSW]

I did a bit of digging on Victors site as my wireless connection would allow me.

 

 

 The difference between the STK-9 and STK-11 appears to be that the 9 has a single burner, and the 11 a "double barrel" burner. I can't find exact specs on the 9, but the 11 shows it capable of silver brazing up to 3" and soft soldering up to 6" ( I'm assuming the mean pipe not solid for obvious reasons)

 

The STK-11 shows it can  silver braze 1/2" to 2"  ( soft solder to 4") with Propane  and silver braze 3/4" to 3" ( soft solder to 6") with MAPP.

 

From what I can tell I'm going to guess the 9 is close to the same capacity the TX 504 below is capable of, but that's just a guess based on one other torch they had listed in the sales lit.

 

The TX504 shows tips available to silver braze 1/4" to 1"  ( soft solder to 3") with Propane  and silver braze 1/4" to 1 1/4" ( soft solder to 4") with MAPP. It also has the self lighting option the other two do not have.

 

 

I found this info in the Extreme sales literature that I located by pulling up each option on Victors site. Here's the page for the STK-9 that has the " Extreme" literature linked.

 

http://www.victortechnologies.com/products/detailProduct.html?prodID=0386-0403

 

 

 

 

I can't say if these will accomplish what you want or not. The STK -11 seems a bit overkill for small work. It's really for sweating large pipe. Also I'm going to guess silver solder is about the max these might be able to braze. Brass brazing may be beyond their capability, but I'd have to check melting temps on the brazing rods. If the temp for brass rod is lower than that for sil solder you should be good. If it's higher, I'm going to guess you'll need more heat. Also keep in mind the flame size on these is moderately large compared to say even a medium sized Oxy fuel tip. Oxy fuel would give you more control over the area heated as well as more heat output. Oxy would definately get hot enough to brass braze. I'm not sure why you might be leaning away from Oxy Propane.

[catceefer]

DSW: I shied away from oxy/propane in the end for two reasons: even with a donated oxy/acetylene set, the initial costs were going to be over £100.00 and secondly, safe and convenient storage of the oxygen tank.

 

Anyway, to finally put this to rest: I bought a Victor Turbotorch STK-11 (uses MAPP or propane) and tried it out this morning on just propane.

 

I have to confess that I was most impressed. Within a very short time, I had successfully brazed two 0.5mm collars together with the pieces in the open air. Trying this originally with my old torch, even with surrounding and filling the pieces with refractory material, it barely heated the parts enough to melt the braze, let alone join the parts securely. This new torch makes my original propane device look like a candle in comparison.

 

Thank you for all of the advice,

 

James.

 

[That Wheelie in Australia]

MAPP gas can burn up to 30% hotter if the torch produces a swirl flame. I braze 0.5mm (19.685 mil U.S.) copper in a make-shift oven. I'm making a bunch of lotus flowers below a watering can as a solar powered garden water feature. Solder would do the trick but I prefer the strength of brazed joints. Not as complex as a dragon but what the wife wants, the wife gets. Good luck mate, would love to see a pic when you're done.

That Wheelie
Australia

[Irondragon Forge ClayWorks]

Welcome aboard Wheelie. We won't remember your location once leaving this post, hence the suggestion to edit your profile to show location. This thread gives a lot of tips for getting the best out of the forum. READ THIS FIRST