Superheater pipe repair

[Colin ReedParticipant @colinreed51485]

My son has asked if I can repair the superheater pipe from his 3″ Atkinson steam lorry, which failed on a steam rally last weekend. I’ve attached some photos below.

It’s made out of thick walled copper and I’m assuming the two halves were joined at a tight angle due to the fairly narrow central tube the pipe goes down to the fire box.

I’m unsure how the pipe was originally joined. Where the halves broke away there are what look like gold coloured lumps of metal.

We’ve got access to silver soldering and tig welding equipment, so any suggestions on the most appropriate method of joining the bits back together would be very welcome.

Colin

 

[noel shelleyParticipant @noelshelley55608]

looks like someone tried to braze the joint with silver soldering heat and failed – miserably ! Either remake in stainless and tig weld or clean up the ends and re braze with sifbronze. You WILL need plenty of heat and brazing or HT5 flux. Good Luck, Noel.

[Clive Brown 1Participant @clivebrown1]

I’d think that the joint for the original construction was either brazed or a high mp silver solder. Perhaps not ideal for something directly exposed to an intense fire especially if and when there is no steam flow to give a cooling effect. Sifbronze at least seems required for repair. Tig would probably be better if possible but a good clean-up is needed. As said above stainless steel and tig would be best for the tube length actually in the firebox.

HTH

[bernard towersParticipant @bernardtowers37738]

Its amazing what things manage to get through a steam test as parts of that joint have never been joined by braze, must have been a good fit.

[duncan webster 1Participant @duncanwebster1]

If the superheater is downstream of the regulator it isn’t part of the system tested in either hydraulic or steam tests.

[ZanParticipant @zan]

Here is my Atkinson superheater, it’s out because of a damaged o ring and it leaked

the spear and Down tubes are both stainless, soldered with sifbronze which is of course very high temperature.     I added very large solder fillets th give a stronger and more reliable joint.  The top spiral tube is copper hence the junction block

irecently had the.
same problem, the spear was leaking it transpired that the original bronze block had partly melted ( or severely wasted).  It lasted  10 years     the problem here is that the superheater is upstream of the regulator and is thus always pressurised and has nothing to absorb the heat

because of the high temperatures involved I advise you not to use the jointing method

as shown in your original post  just not enough area to seal the joint   The heater is part of the pressure test

[FulmenParticipant @fulmen]

I’m no welder, and I have only tested TIG on copper out of curiosity. But if you’re proficient with a TIG welder I don’t see what could go wrong (famous last words).

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