Story to tell, not really for the Fettling Forum since it raises an issue I thought might be worth a Stove Forum exchange of views. It's the topic of the occasional - and as here occasionally stupid - manufacturing faults that emerge 60 years or so down the line (in the case of the stove featured in this post). The Burmos 96 needed a new non-return valve 'pip' to replace the cork original. Symptom was the pump shaft telescoping out when the tank was pressurised. When I came to engage the NRV removal tool and apply the usual action of push (gently, but enough to stop the tool camming off the NRV flats) and turn, the stopped end of the pump tube complete with NRV came off and ended up inside the fuel tank. Simple enough disassembly to put matters right ... ... but when I'd retrieved the pump end stop and NRV and took a closer look I saw that it was a clear case of inadequate assembly work at the factory, with no tinning of the surface here ... ... or of course on the corresponding surface on the pump tube Resoldered end stop and tinned mating surface for the fuel tank joint Soldered up, cleaned up, fuelled up and ready to go That pump end stop was hanging on by a whisker of solder around the rim of the pump tube and for most of its life - up to the point when a new NRV pip was needed - it functioned ok. Manufacturing fault, but no chance of a warranty return here! John
Nice clean work John 8) , you make it look so simple 8) took me a few try's to get it right when i first started but now with a little patience & an old stove to practice on any fettler should be able to salvage their stove just need to jump in & have a go 8) Stu
Gracious comments coming from a master fettler, Stu, but have you noticed any manufacturing faults of this sort .. ? Sticking my neck out here as a Brit myself, but though I've not kept records, I'm pretty sure I've had more British stoves to put right - manufacturing faults and not just worn-out consumables - than Swedish ones ... I'm thinking, in automobile terms, Volvo Amazon V Standard 10. John
Hi John, I had a similar problem with a Burmos 21 ( Link ), but in my case the entire pump tube shot into the tank when I tried to unscrew the NRV! Regards, Terry
Hi Terry. Kicking myself for not having spotted your Burmos post first time round. Made a good and inspiring read! Something of a classic (the post as well as the Burmos) for the tenacity you showed getting the thing to work. Looks like the evidence is mounting to establish the examples in stove manufacturing industry of the 'Friday afternoon' assembly job. Two to Burmos so far. Not good. John
Hi John Excellent repair! And, yes, I've encountered similar production flaws involving poor soldering. I can think of two examples where the pump tubes leaked at the font join because there was only a vapor's trace of solder in thirty or so degrees of the circumference of the join. Elsewise, I'm sure you recall the upside-down fuel pickup in my military #12. I think that qualifies as a fault. Link Cheers, Gary
That's a nice repair job John, it's good to see invisible solder jobs like that. Here's another fail for Burmos I posted a while ago. In this case the flaw was cracking at the end of the pump tube, presumably from forcing an over sized NRV end piece into the pump tube. Cheers Colin
Hi Gary, Colin. Yes, I remember the Military No.12 (crazy one that was) and the Burmos example. Oh dear, our beloved Brit stoves aren't putting up a good show so far! Mind you, the worst manufacturing fault that can write off a stove, unlike a dodgy bit of soldering, is stress cracking and I've certainly had my share of those and they've not been British stoves Chinese (Solar) stove stress cracks That one I repaired because a brass patch plate seemed to suit the stove, but I've even had stress cracks that haven't (yet) sprung a leak Graezea from Ehrich & Graetz Meva's have something of a reputation for stress-cracks in the fuel tank as had some 'budget' versions of Primuses where to shave some pennies off the retail price the gauge of brass in the fuel tank was thinner and more prone to cracks. John
Oh, my! Yes, John. Stress-cracking. Hadn't even thought of that, but I suppose that *is* a flaw, too. OK. No British stoves in this group. From memory, and, sadly, some really nice stoves otherwise... Norma 25 Optimus 1 "Traveler" w/the bun feet Juwel 41 1912 Primus 7 The first three were unrecoverable - horrible widespread cracking. The Primus 7 came to me with a wide band of copper sheeting wrapped around and soldered on the tank. I don't *know* it was stress-cracked... but why else would someone go to that trouble was my thinking? You can see it here on the left in the photo from the OSG (Oregon Stove Gathering). Thats a Primus 34 to it's right - don't recall the year. Cheers, Gary
Don't get me started : 1) No heat proof paint on the preheating area of a steel stove, like the Juwel 34 or Phoebus 625. The paint burns off during preheating ... 2) Making stoves out of steel instead of brass; sooner or later they'll rust (especially when burned ) 3) No heat proof painted case/tank whereon fuel can leak and burn (Optimus 111, Juwel 34, Phoebus 625, Coleman suitcase) 4) Generators that cannot be taken apart for cleaning (and discovering that whilst camping) . Nice moneymaker for the manufacturer though. On the other hand, if all stoves where bombproof then nobody needed to buy a new one . Also durability costs. That's all not good for the manufacturer Besides, perfectly durable stoves wouldn't need fettling . So thank the faulty, flawed and erroneous stoves for their contribution to this fettling forum
The patch method of repairing stress cracked tanks seems to be the norm, but I was wondering... What about a method of crack repair which would involve drilling a hole at the ends of the crack and brazing the crack. Possibly putting a "V" into the crack to help the braze repair. This would have the advantage of being almost invisible once finished and polished. Has anyone tried this with tanks? I wonder if it would be strong enough. I haven't had a stress cracked tank to repair, something to look forward to. Cheers Colin
When I was in Jr. High School,(7th-9th grades) we had our choice of shop classes, Craft, Mech. Drawing, Metal, Wood, Home Economics. As there were six semesters and the shop courses were not mandatory I took Mech. Drawing one semester, Home Ec.(Cooking) one semester, Craft Shop one semester and Metal Shop three semesters. A skill one had to master was soldering, especially soft soldering and sweating. I thank my lucky stars that shop was still a relatively important course of studies when I was in school. Now, of course, "Manual Arts" is just another Mexican kid. Learning to do useful things is just so dark ages these days. Much more important that little Arturo and Fabiola feel good about themselves. I even took two semesters of Latin. Which I failed miserably even though the teacher was one of my favorites. Teaching Latin to a half Norwegian teen ager must have been a trial. All I remember is: Amo, Amas, Amant, Amamus, Amatus, Amant. Miss Hilgenkamp did her best though, instilling in me a budding appreciation for discipline and systematic learning. Both have stood me well over my lifetime. Hardly her fault that Latin, as did Algebra couldn't find toe holds in my well armored brain. Later on German, Celestial Navigation and Spanish found fertile soil. How's that for some mixing of methaphors? Anyway. In Metal Shop we made things of copper, brass, steel and alumin(i)um by rivetting, soldering, spinning, bumping, casting (I still have my own hand cast alumin(i)um skillet.) and forging. Dirty, noisy, smelly and altogether great fun. I especially enjoyed soldering. Learning to anneal, fit, then assemble and solder. I'm of the opinion that stress cracking in objects made of sheet brass is the result of improper annealing during manufacture. Whether it's a decision made in the commiseriat or just an oversight or unknown factor in manufacturing is a good topic for discussion. In free European manufacture, I'm inclined to believe it's just an oversight, but in some places, especially those run by the Godless Commies, it seems to be general practice. As in any method of keeping costs down. Many items I've seen from Communist countries don't seem quite up to snuff anyway. A la Bat stoves and Yugo "cars". Although Chinese stuff is getting to the point of being darned good, especially knives and hi-speed cutting tools. I've also got a small 7"X12" Chinese made lathe and a wee Chinese made vertical mill. Harbor Freight #'s 44991 and 93799 for those inclined to have a peek. I've had those for over ten years and regarded them as pre-assembled kits anyway. Getting them properly, cleaned, polished, fitted and adjusted was half the fun. At the time expecting them to be fully functional was begging for disappointment. Brazing an object assembled with soft soldered or sweated joints could be dicey, the heat needed for brazing could very likely destroy soldered joints. The heat would also anneal the brass around the brazed joint inducing stress against the further surrounding areas. I tend to regard any part with a stress crack as ruined, relegating the object to the parts bin or solely for display. The soldered copper sheet wrap is a darn clever work-around though. Someone was thinking. ol' Gerry
Presscall I am amazed at your repair skills as well as ability to narrow down the problems in these stoves and over come the problems. Lots of respect to both you and Bernie Dog for your craft.
Very kind comment, Viscara, thank you! Interesting stuff has emerged. I'm with Thuggie on that possible fix for stress cracking involving brazing. Realistically, there'd be no way of isolating the heat required to silbraze from the soldered base seam. Water in the tank, wet rags on the outside, ok for some soldering jobs but too much of a heat sink for silbrazing (I've tried). You'd have to be willing to de-solder and disassemble every part of the stove first. Pot rest fittings, pump tube, easy. Filler riser, not so easy since they were often swaged over from inside the tank as well as soldered I've noticed, so that would have to be de-soldered and prised out. Burner riser tube and base seam ... mounts up as a real headache. John
Hi John, I've also had a couple of pump tube issues with Burmos stoves. A quick glance through the other posts suggests that manufacturing faults on the pump tube was a common issue. Yet I've never seen problems in other areas of these stoves with them generally being of good construction. If their soldering wasn't up to snuff generally you might think that tanks would leak and there'd generally be issues in other areas. So, I wonder if pump tubes were a subcontract component? The worst problem I ever had with a stove was on an Enders Baby. The end of the pump tube on that stove had absolutely no solder present and seemed to be push fitted. Dunno if it fell on the floor and missed the soldering stage or what. Also the walls of the pump where incredibly thin and suffered from stress cracks. I bought it unfired so was very lucky I checked it out before I tried to use it. Cheers, Graham.
John David Shouksmith had a gorgeous Buflam stove, that looked like it had never been lit. That was because you couldn't light it, it had no fuel pick up in the tank. You could prime it, pump it, hear it hiss but only air came out.
Now this is funny - I have one just like that - Burmos 21 and the end of the pump tube is "coned" out with four or five cracks around the end - from new we think. I've had to pass that on to Stu to see if he can sort it for me as it's beyond either my or my brother-in-law's skill to repair!
I guess I was lucky with mine. It had what seemed to be black silicone rubber in the bottom of the pump tube, I got it cleaned out though. The only trouble I had was the gallery fell off and I had Bernie Dawg braze it back on.
