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As Ken has said Rickmans used 531 tubing and the standard way of joining it was by bronze welding, also known as fillet brazing. In this process the base metal is brought to dull red and the bronze filler metal melted into to it to form a fillet around the joint. At no point should the base metal get raised to its melting temperature otherwise the bronze will boil off and make a huge mess. Since the base metal doesn’t get as hot, bronze welding is a useful repair process for use on steel in general since there will be less chance of the heat affecting surrounding items and finishes. Bronze welding of 531 is done using an oxy/acetylene torch and a gas fluxer. The gas fluxer is just a bottle with boric acid in it through which the acetylene is passed. This produces a green flame with the flux in it and hence produces a very clean joint with no flux clean up required. The rod used these days by the current practitioners of 531 frame building is SifBronze 101 which is I believe formulated to be easier to build up fillets. If you live in UK you can buy it at many welding supply places - if you live in USA you can probably find an equivalent bronze rod by comparing the maker’s chemical composition listings. It might not be quite that simple since I believe the Sif Bronze 101 had its viscosity/cooling characteristics optimized for the buildup of fillets.I have had to have repair work done on my Seeley frame ( bronze welded 531) on a number of occasions and initially my friend, (the late Les Cook) taught himself to bronze weld and did it for me. After he passed away I found a local bicycle frame builder of custom high end steel frames here in Seattle who could bronze weld using a gas fluxer. It turns out there is still a pretty widespread cottage industry here in the US making custom steel frames using bronze welding. It might be worth checking your local bicycle scene. Another source of people familiar with bronze welding high tensile steel tube would be specialist vintage sports car restorers. I believe early space frame Lotus’s used a 531 tubing bronze welded chassis and the Jag E type ( XKE) definitely used that method of construction for the engine/front suspension hangerBronze welding can also be performed using a Tig torch and bronze filler rod (aka Tig Brazing) but is not recommended for 531Re your BSA sidestand repair, and as mentioned above, if there are any other brazed lugs in the vicinity then the heat from any kind of repair process on the sidestand lug could create issues. Bear in mind that I am just an owner of a 531 frame that had to be repaired, not an expert welder, but hopefully the above will have given some direction on where to find out more info.Duncan
As Ken has said Rickmans used 531 tubing and the standard way of joining it was by bronze welding, also known as fillet brazing. In this process the base metal is brought to dull red and the bronze filler metal melted into to it to form a fillet around the joint. At no point should the base metal get raised to its melting temperature otherwise the bronze will boil off and make a huge mess. Since the base metal doesn’t get as hot, bronze welding is a useful repair process for use on steel in general since there will be less chance of the heat affecting surrounding items and finishes. Bronze welding of 531 is done using an oxy/acetylene torch and a gas fluxer. The gas fluxer is just a bottle with boric acid in it through which the acetylene is passed. This produces a green flame with the flux in it and hence produces a very clean joint with no flux clean up required. The rod used these days by the current practitioners of 531 frame building is SifBronze 101 which is I believe formulated to be easier to build up fillets. If you live in UK you can buy it at many welding supply places - if you live in USA you can probably find an equivalent bronze rod by comparing the maker’s chemical composition listings. It might not be quite that simple since I believe the Sif Bronze 101 had its viscosity/cooling characteristics optimized for the buildup of fillets.
I have had to have repair work done on my Seeley frame ( bronze welded 531) on a number of occasions and initially my friend, (the late Les Cook) taught himself to bronze weld and did it for me. After he passed away I found a local bicycle frame builder of custom high end steel frames here in Seattle who could bronze weld using a gas fluxer. It turns out there is still a pretty widespread cottage industry here in the US making custom steel frames using bronze welding. It might be worth checking your local bicycle scene. Another source of people familiar with bronze welding high tensile steel tube would be specialist vintage sports car restorers. I believe early space frame Lotus’s used a 531 tubing bronze welded chassis and the Jag E type ( XKE) definitely used that method of construction for the engine/front suspension hanger
Bronze welding can also be performed using a Tig torch and bronze filler rod (aka Tig Brazing) but is not recommended for 531
Re your BSA sidestand repair, and as mentioned above, if there are any other brazed lugs in the vicinity then the heat from any kind of repair process on the sidestand lug could create issues.
Bear in mind that I am just an owner of a 531 frame that had to be repaired, not an expert welder, but hopefully the above will have given some direction on where to find out more info.
Duncan
