How to weld a space frame?

[stephen wilson]

On the older english chassis, is there not a problem tig/mig welding at any area that was previously bronze welded no matter how clean of weld material the metal was?

Dave Coughlin

It can "pop" if you hit some residual bronze, but it's do-able. You have to grind all the braze off to TIG, while not taking away too much base metal. MIG is much more forgiving.

[spaceframe7]

I have just received a reply (March 2014) from Murex (U.K.) technical section that they have moved on from gas bronze welding and their nickel bronze rod and associated fluxes are no longer available. The technician did advise that their nickel bronze rod (C5) was almost identical to Sifbronze No. 2, had the same welding temperature range, and identical u.t.s. (540 N/mm2/78,320 psi). I am still waiting for a reply from Weldability (Sifbronze) regarding advice on the availability of their products.

Further Postscript:
Two welding supply companies in Poole, Dorset U.K. contacted me, and both can supply Sifbronze No.1, No.101, and No.2. One gives a v. good discount on any of these rods. Note however, that No.2 Nickel Bronze rod is over twice the price of No.101. One of the companies advised that Murex did not manufacture their own bronze rods or fluxes, but instead sourced them from Weldability Sif. This would explain the identical specifications. Brian Ashcroft, who I have mentioned for his three 'YouTube' videos "Ariel Atom Bronze Welding", "Bronze Welding V8 Ariel Atom", and "Bronze Welding" advised me of the following: "I have used the (Sif) No.2 and it does weld very similar to No.101, just doesn't run quite as nicely. We found that the No.2, although having a higher u.t.s. did tend to be more brittle than No.101 which is why we prefer 101. I haven't come across a weld failure with 101 yet in my 18 years of using it."

To the gentleman from Canada who posted that Tig should be the way to go, I agree that in the hands of a competent welder, Tig makes an excellent weld, and is the modern way of joining metals. An aircraft certified welder friend of mine using Tig, could perform magic on my old space frame chassis (which was originally gas fusion welded). Even Arch nowadays use Mig and possibly Tig on parts of their chassis. As has been discussed a couple of times in these posts and noted by yourself, it is not recommended to tig, mig or gas fusion weld over a brazed joint as it can cause intergranular penetration of the bronze into the steel, can seriously compromise the steel, thus creating a weak joint. Owners of vintage sports racing cars that were originally constructed using the bronze welding method, are still likely to choose bronze welded joints over Tig wherever possible, in order to duplicate the look and strength of the original joint (I believe this was the basis of the question originally posed at the very start of this particular thread?). Some other 'YouTube' videos show welders young and old demonstrating bronze welding and silver soldering techniques using oxy acetylene equipment, so it is not yet a dying art. S7