Soldering Irons and butain gas

[David Bess]

looking to get myself a soldering Iron has any one experience of the small gas torches Dremel look good,will they braze and silver solder ? Thanks

[Daithi O Buitigh]

I've a torch here (got in Maplin's years ago) and, yes, they will silver solder. I never tried brazing so I can't be definite on that one

[Alan Randall]

Aldi supermarkets do a good butane soldering iron on a periodic basis for about £15, I think. They were also doing a nice table vice recently for £5.99. Unfortunately I paid £16 for the same, but re-branded, item at the Sandown model engineers show just before Christmas..

[Martin McIntosh]

Hi David,

If you are looking for a gas torch then get one from your local DIY( Wickes, B&Q etc) of the type with a screw on propane/butane can. These are cheap and will braze/silver solder u/c legs etc. Don`t touch the tiny expensive ones.

I solder electronics professionally and although this is a cheapo, can recommend a temperature controlled soldering station which will last you forever @£34.95 from CPC.co.uk. The bits are only £1.09 to boot.

Catalogue No. SD01116.

Edited By Martin McIntosh on 18/03/2012 18:30:31

[David Bess]

just to answer my own question Daithi silver soldering is brazing

"Hard soldering" or "silver soldering" (performed with high-temperature solder containing up to 40% silver) is also often considered a form of brazing, since it involves filler materials with melting points in the vicinity of, or in excess of, 450 °C. Although the term "silver soldering" is used much more often than "silver brazing", it may be technically incorrect depending on the exact melting point of the filler in use. In silver soldering ("hard soldering", the goal is generally to give a beautiful, structurally sound joint, especially in the field of jewelry. Thus, the temperatures involved, and the usual use of a torch rather than an iron, would seem to indicate that the process should be referred to as "brazing" rather than "soldering", but the endurance of the "soldering" appellation serves to indicate the arbitrary nature of the distinction (and the level of confusion) between the two processes. Thanks Alan I will look Aldi online

[Martin McIntosh]

I got some silver solder, loads of it, on ebay for about a tenner. I think it came from a guy in Milton Keynes. Much easier than (brass) brazing. You also need the flux which Nexus can supply. The above mentioned torches will also do aluminium welding using Techno Weld if you are brave enough.

Martin

[Daithi O Buitigh]

True David, I never thought of it that way - just I always considered it to be different as (to me anyway) 'brazing' is using brass (CuZn alloy) as opposed to silver

[David Bess]

Got a GoSystem hobby torch butane /propane gas mix , good blue jet with a white point just at the tip of the blue I guess that to be the hottest spot 1450 c ,should do the the job . B&Q Fine flame torch and gas under 20 quid

[Shaunie]

Just one small point...The temperatures required to achieve a good silver soldered or brazed joint can anneal music wire. You make a lovely job of the joint and when you make your first landing your wheels are pointing in different directions. Don't ask how I know!

[Martin McIntosh]

In most cases a wire wrapped soft solder joint is all that is required for u/c legs. If you must use some sort of brazing, quench the joint whilst still cherry red, polish up with sand paper until most of the metal is bright then reheat gently until it turns to straw colour. Allow to cool slowly. Not great but it works for me.

Martin

[David Bess]

thanks Martin the quenching and bringing back to colour tempers the metal ,poor Shaunie took the temper out the wire so it became soft, quick cooling hardens the metal but can be brittle so heating again to the colour makes it springy again my dad served apprentice for a blacksmith , but thanks for the tip. He made me a hunting knife once and showed me how to temper it cherry red and quench this makes it hard but too brittle to keep a good edge as the edge becomes jagged easily so he heated to a yellowish and quenched in oil , it also gave it a nice blue colour. Thanks or taking the time to read and input always appreciated

[Daithi O Buitigh]

I always dunked anything that I used a torch on in Fluxite (does the same thing in giving the blued steel) I never knew about the oil - thanks for that

[Erfolg]

Unfortunately heating a high carbon steel, which has undergone a heavy drawing process, such as Piano Wire, to cherry red will have altered the structure significantly. Perhaps the most significant issue is that the distorted grains/crystal structures due to the drawing process, will inevitably adopt an energetically favourable shape and structure, which is engineer/scientist speak, for in this case strain energy will be released and grains will become rounder. That is in addition to a phase change, in principal.

The rapid cooling will lock in the structure in FCC (Face Centred Cubic), which is much denser/harder, but brittle. The faster the cooling the greater will be the remaining FCC, slower cooling will allow the structure to have more BCC (body centred cubic). In principal. Water transfers heat away more effectively than oil, air cooling is much slower still.

The addition to alloying elements can alter the so called Cooling Velocity Profile, which determines the cooled properties.

The subsequent heating process allows some of the structure to change to a less densely packed structure.

I have simplified both the terminology, eg not using terms such as Austinite, Pearltite, Martinsite etc. (all for you Daithi), as it leads to yet more questions and issues. In addition I have ignored what is found commonly in the grain boundaries and so forth.

The bottom line is the heat treatment process, will not FULLY restore the original properties. The wire preferentially bending or breaking in the HAZ (heat effected zone) adjacent to the treated area, dependant on what is subsequently done.

It is a pity that a practical aesthetically pleasing mechanical joint cannot be used in many of these types of applications/situations.

[Daithi O Buitigh]

Well I used Fluxite (it's just a solder flux paste in a tin) because I always had it for work (retired electronics) and it was great for keeping the iron bits clean

I just checked on the net - and they haven't changed the design of the label since I first used an iron

[Martin McIntosh]

What a lot this wonderful hobby teaches us. I was taught how to harden/anneal metals using heat/ fast cooling/ very slow cooling/ immersion in oil when at school but it is too long ago to remember the details.

For your interest, I only use Telux flux for soft soldering piano wire or brass. It is none corrosive and much better than Fluxite. Essential for good linkage joints.

I would love to know what manufacturers use to get those perfect alloy welds on silencers etc.

Martin

[Erfolg]

When you say alloy, I am assuming Aluminium alloy? If so then Argon Arc (trade name) is a possibility. TIG welding can normally be using a manual feed or motorised feeds (AA being one of the first).

If the alloy is Brass, I would assume a Brazing technique. Which normally gives a good profile, even for the low skilled. Same goes for Silver Soldering.

In all cases, obtaining a very good fit is a prerequisite of any metal joining process.

[David Bess]

Erflog your depth of knowledge never ceases to amaze me , how do you know so much technical info on the subject are you an engineer of some sort ?

[Erfolg]

I took an Engineering Degree and was a Chartered Engineer. I also took additional studies (lasting many months) over the years in materials as well a Computing Science.

The surprising aspect for me was the development in the understanding of material science over 50 years. It changed from a art based subject to a science based subject, where the observations in the art, have become explained in scientific terms, where an emphasis on projection/anticipation of properties.

[Erfolg]

I have just been moving stone of the lawn, as a consequence of having a new fence installed. Although they cleaned up a lot , there was still some heavy work to do to finish the job. This process gave me plenty of time to think.

My mind went back some 40 years, when I worked for BICC, a business now (what is left) incorporated into our "Old Austrian Friends". At that time there was a problem with some Armoured Cable, being a junior engineer I was on the periphery of events. In essence the strands were unexpectedly failing or breaking. There was two schools of thoughts, one was that the jointing process was the issue, the other that it was unrelated. At that time some metallurgists thought that the changes in structures changed at specific temperatures, others that the change was energy related, that temperature was part of the issue. Some seeing changes somewhat like water, it boils at 100C, others ore like toffee, that the structure changed with time and temperature. Much academic work was invested into the issue.

This reminds me a little of the tempering process. The workshop techniques do work effectively. A bit more science enables you avoid pitfalls that could arise from soaking.

Although I am not or was a Materials Engineer, the advances that of occurred with X Ray Cryptography, Electron scanning techniques and many, many other methods, has allowed theory to be confirmed and myths to be debunked. Other techniques which came common place was understanding the crystallography, atom sizes, how elements were incorporated into the lattice. Perhaps blocking slip planes , and much else has amazed me.

The last course I undertook was with respect to polymeric materials. Again much was intuitively known, but issues such as Loading Rate, Temperature effects, were recognised with metallic materials, such as Izod impact tests, creep, viable range of temperatures etc for most purposes were considered of little importance. All of these effects are often significant with polymers.

Materials technology is truly very interesting, but then again, engineering in general is very interesting at all levels. Although I would emphasis that in my opinion, it is a science not just a craft. As can be seen in F!, if you want to win, you need a good grip of all aspects, from science to manufacturing.

Edited By Erfolg on 23/03/2012 12:11:09

[thomas oliver 1]

I once visited a factory in Leeds making aluminium kitchenware. A guy was "brazing" the spouts onto teapots with a small blowtorch, silicon alloy rods and flux to suit the rods. The result was a beautiful filleted joint. I bought the rods and flux, which unfortunately had a terrific affinity for water and was costly then. I was quite successful in making nice joints and even taught boys to do it. The flux soon became liquid and would not work, so I never pursued this method. Later I bought two different types of rods at B&Q store - Taymar brand I believe. One was a fluxed rod for alloy ,and the other was a non fluxed rod. I successfully made many alloy headers for petrol engines for friends with the fluxed rods using a medium sized nozzle on my Seivert torch. The other rods were similar to technoweld rods and worked equally as well if you used the technoweld technique using a SS spike and a SS wire brush. I fixed the detached flange back on the downdraught carburettor of an OS 40 FS and lots of other jobs using this last method. So there are several choices of processes for joining aluminium alloy. I was in B& Q last week and they do not appear to stock Taymar branded rods nowadays but they do have various silver soldering rods.