Hi everyone, This is my first post on the forum, so I just wanted to introduce myself. I'm Mick I’ve recently been working on a British Army No. 12 stove and due to my noob mistake have run into an issue with it. After trying to decoke it by quenching it has developed a crack from the pipe that runs up from the control valve, and I’m looking for some advice on the best way forward. I'd love to have a go at brazing it but dont have the kit I’ve got a few questions I’m hoping someone with more experience can help with: Is there anyone in the UK who services these stoves and could repair the burner head so it’s properly gas-tight again? Are there any alternative repair methods or workarounds people have used successfully? Would attempting a DIY repair with a blowtorch and soldering iron be viable, or is that likely to cause more harm than good? I’ve also come across full replacement burner heads for around £100 from I Walker, so I’m weighing up whether spending miney on brazing equipment or replacement makes more sense. Any advice or pointers would be greatly appreciated. Thanks in advance! Mick Mods Sorry if this post is in the wrong section please move if necessary
Yeh it was a moment of stupidity on my part I should have known better. Gutted as they are a great stove. I hope I can resurrect it somehow.
Not really, there are loads of old threads on this site with outdated ideas like cleaning burners by heating and quenching, using ammonia containing polishes such as brasso*, and polishing beautifully weathered stoves**. There have been a few cases where it has caused cracking so a lot of us with equipment to use heat and air take this safer (and arguably more reliable and thorough) option. *not scientifically proven but a lot of us are suspicious enough to steer clear. **ok, the last one was intended to be a troublemaker.
@mickeytee A couple of questions Mick:- Why the attempt to decoke? I’m interested to know what symptoms the burner presented to lead you to conclude that it was choked with carbon deposits. Secondly, tell me something about the crack in the burner tube. I can’t see it in your photo, but is it visible or is it only apparent when fuel vapour comes from it (and ignites) after priming the burner and opening the valve? Is it a crack part-way down the tube or perhaps has developed in a brazed joint? Thanks John
Hi John thanks for your reply. In answer to your questions I decided to attempt a decoke as when I received the burner it took several preheats to get going and when it di it burned with a very yellowy sooty flame. the previous owner said it had been running on pump diesel. I have found the leak by putting the burner head in water and blowing through and it isnt coming from the pipes but is a pinhole leak I've attached a photo pointing to where it is in the recess. The leak becomes apparent when you prime the stove after preheating a flame shoots out from underneath the burner and stays lit till you depressure the stove. Hope this answers your questions thanks for replying. Mick
@mickeytee That's fixable by the looks, and John @presscall is the right person to talk this through with. Cheers Tony
@mickeytee I expected the use of diesel was likely to have been the cause of premature coking-up. Though specified by an army contract to use diesel, the squaddies no doubt have had stacks of spare burners to draw on when a burner became unusable. I didn’t suppose it was a crack in a burner tube, but a pinhole leak developing in a brazed joint is usually how a burner springs a leak. Send me a message (Inbox/Conversations at the page heading) and we’ll swap addresses for me to repair it. John
Thats great since posting I've read a little more about brazing and I think I would like to do that if I can I've seen a cheap torch on amazon that might do the job Amazon.co.uk I think I need high temp flux and silver solder aswell but I shall await @presscall reply. Thanks for the reply
@Pharael Thanks P, but Mick explained his dilemma well and it seemed like a neighbourly thing to offer because I can. John
@presscall you just want to keep your fettling skills up in the 99th percentile. The burner you repaired for me is still going strong so I can vouch for the experience. Regards John
@Jeopardy Well, it had me intrigued from a fettling point of view I must admit. Glad a repair stayed repaired! John
@mickeytee Repair’s completed. I began by priming (with meths) and firing up the burner (on paraffin/kerosene) on my No.12 to pinpoint the leak, an alternative method to your pressurising the tank with no fuel in and dunking the burner in water, Mick. Sure enough, a jet of vapourised fuel was emitted from the pinhole and on igniting deposited soot on the burner. Air screw opened, burner allowed to cool down, removed from the tank and examined. A tell-tale flash of brass at the pinhole where the escaping gas had cleared away the soot disclosed the exact location of the leak. It was then simply a matter of cleaning the workpiece where silbraze was to be applied … … and setting the burner on firebricks, regulator spindle/jet/pricker rack/brass gauze in the inlet pipe all removed to ensure fuel residue in the burner would burn off harmlessly without generating pressure in the voids as it vapourised. A butane blowtorch provided a broad non-intense (soft) flame to supplement a fine, MAPP ‘torch flame. This ensured intense localised heat at the point of the repair which would not be conducted away by the mass of burner metal surrounding it because of the heat-soak action of the butane output. Silbraze chosen had a relatively low silver content (30%) with a correspondingly much higher melting point than any temperature reached by the burner. Silbraze flooded over and around the pinhole. Burner cleaned up, reassembled and installed on my No.12 to test. @kerophile introduced us to the ‘tea test’, so of course I followed suit. John
Oh wow! Thats a first class job right there John. Thanks so much for your help repairing this I really appreciate it. It looks fantastic. Interesting and detailed repair report thank you for sharing. Mick
