[CR]lugged frames v. fillet brazed..now bronze-welded.

(Example: Framebuilders:Jack Taylor)

From: "Norris Lockley" <norris@norrislockley.wanadoo.co.uk>
To: <Classicrendezvous@bikelist.org>
Date: Mon, 5 Dec 2005 01:57:10 -0000
Subject: [CR]lugged frames v. fillet brazed..now bronze-welded.

As I started this particular hair running by doubting whether there is such a process as "fillet-brazing", this in my mind being clearly a contradiction in terms, and in view of the responses provoked from Phil Brown and Greg Parker, and further queries raised by Harvey Sachs..about silver solder, and by Stuart Tallack seeking definitions, I thought I should tried to explain my statement further

While I stated that by using the brazing process one cannot produce a fillet/bead/cordon, I accept that by using a brazing /bronze-welding rod with a high and wide solidus-liquidus temperature linked to a suitable composition of alloy and flux, it is possible to produce a bronze-welded bead or cordon..

Clearly as there are different definitions of the terms brazing, welding, soldering, melting, fusing and wetting in the States from those used in the UK, although I think we all know what is meant by a fillet, o a bead, or a cordon, I will offer the List a set of definitions produced by Johnson Matthey, one of the leading specialist manufacturers and suppliers of brazing and soldering rods in this country. However I think that the parent company is American. It wouldn't help at all in this debate to invoke French definitions, because they use the same word for soldering and welding, -"souder" thereby ignoring the vast difference in the amount of heat involved in the two processes, but do have a specific word for brazing "braser", but this is seldom used, as the French prefer to keep things pretty tight and use the word "soudobraser"

Definitions of processes using various types of "brazing" rod, as printed in the Johnson Matthey Manual:-

BRAZING -is a process in which the filler metal is basically composed of one or more of the metals beginning with aluminium, in ascending order of melting temperatures.applied in such a way that although a fillet may be obtained, the PRINCIPAL aim is to cause the filler metal to penetrate capillary gaps between the components being joined. BRONZE WELDING or BRAZE WELDING- is a process in which the filler metal is basically a copper-zinc alloy,(it may contain also nickel, manganese, silicon or tin)appplied in such a way that although some penetration of the filler metal may be obtained into capillary gaps between the components being joined, the main objective is to obtain strength in the joint by building up a fillet or bead of the deposited metal. In this welding process no fusion or melting of the parent metal takes place. LOW TEMPERATURE BRAZING is brazing in the temperature range of 600C to 850C using filler metals based mostly on the metals silver and copper. This process is also called silver brazing or silver alloy brazing. SILVER SOLDERING and HARD SOLDERING are terms synonymous with low temperature brazing SOFT SOLDERING employs, as brazing, a filler metal to penetrate capillary gaps between the components being joined, the filler metals having relatively low melting points, such as tin and lead.

The manual goes on to point out that because silver/copper alloys have lower melting points and tend to flow far more easily and quickly than copper/zinc alloys, the gap between components to be brazed must be far smaller in the first case than the latter. From reading and rereading this manual I am beginning to suspect that the UK definition of a fillet could well differ from the American one. A fillet can mean, it seems, that very small curve of filler metal at the joint of two components, a curve having sometimes a radius of less than 1/16"th, and a miniscule leg-length.

It is interesting to note that none of the sales leaflets of all the major UK producers of welding, brazing and soldering materials, ie Johnson Matthey, the British Oxygen Company and the Suffolk Iron Foundary (makers if SIF-Bronze products), list a brazing alloy under the definition "Fillet-brazing" but all list bead-producing materials under the definition "Bronze-welding".

The majority of UK frame-builders used to use SIFBRONZE No 1, a material, normally in rod form, with a melting range of 875-895C that the manufacturer states is ideal for "the brazing and bronze-welding of steel".

One other aspect of building up beads puzzles me. When, let me say, I am bronze-welding joints with a copper/zinc/silicon rod such as SIFBRONZE No1, I have a very wide choice of rods in diameters from 1.4mm through 5 different sizes up to 6,4mm. This means that should I wish to produce a curvaceous bead of sculptural dimensions such as those admired on the frames of Herse, Singer, Routens, Reyhand, Cooper, Hurlow and a multitude of others, I can use a larger diameter rod, say 4 or 4.8mm or even larger, to create that bead in one or two passes and a minimum amount of heat input into the steel. More passes equalling more heat input and possibly more chance of harming the steel. Should I wish to create the same effect using a silver/copper alloy I can only obtain these rods in 1.6 and 3mm, thus entailing more passes over a joint in which the first layer of filler rod would melt very quickly under the application of a second or third pass of the torch, the alloy having a far lower melting point a much more fluid nature. How many passes would it take to build up a French "constructeur" type bead using a silver solder, and how much would it cost? In any case the only silver bearing alloys that I have come across with a wide enough temperature range and a "pasty" nature have their use restricted to the joining of copper, without a flux. I found it interesting to note, when I bought my house in France,that almost all copper plumbing pipes are joined not with soft lead/tin solders, but with relatively high ie 650 - 740C silver/phosphorous alloys. This skill with such products might explain why France produces so many frame-builders adept in the skill of creating lugless frames. In fact one of the finest frame-builders I ever came across, who built many lugless frames for my friend J-M Duret (Geliano), came to the trade from coppersmithing, as did, I believe, Terry Dolan who has enjoyed a very succesful career in the UK as a top builder for a couple of decades.

Just one more reference to the vocabulary of our French friends before signing off. Some years ago before I had really polished up my spoken French I made the error, when asking for a type of jam in a shop, of linking the English word "preserve" with the French word "preservatif". The embarassed assistant kindly pointed out that if she supplied me with what I had asked for, I might find it difficult to spread the product on my morning "croissant" A "preservatif" I learned, has little to do with jam but is the French word used for what I think is coloquially referred to in the States as a "rubber".

Norris Lockley...making sure my wife has put ot the presrves for morning...Settle UK