I'm hoping my experience with attempting to revive a Coleman generator will save someone else a bit of trouble. Having to buy a new generator has doubled the cost of this 'cheap' stove! I got myself a fairly cheap 442 from the 'bay last week and while it ran, it wasn't great and I suspected the generator to be a bit clogged. Although the tank smelled of panel wipe when I got it, it looked to have been run on petrol at some point. So I set to searching on here to see if it was possible to clean them out. Removing the jet and wire first seemed to be the general consensus, then you are good to go. One person said to use low pressure compressed air too. Fantastic, I just got my compressor working again! So I dropped the pressure right down, dug out my blowtorch and set to. I heated up most of the generator to just red, working along the whole pipe. So far so good, bit of smoke as crap burned away. Next I heated up the end with the flare, getting just round the bend from the flare a dull red and started to blow air in the flared end. I then looked to the jet end to see what was coming out, pleased to see loads of thick smoke. Looking back at the other end I was shocked to see an almost white glowing section moving along the pipe and the generator was starting to sag! One ruined generator, where the intense heat was it had fractured as it sagged and cooled. It seems that the compressed air may have been fueling an intense fire inside the tube which heated it to melting point. As it was out of the blowtorch flame that is the only conclusion I can come to. Not impressed! Has anyone else ever had this when cleaning a generator or burner? Simon.
I don't have access to compressed air so only used the blow torch to dullish red. Had flames coming out both ends and this treatment worked on both my 533 and 422. I think the compressed air trick is more recent than when I did mine. It was compressed air not oxygen?
Yes, just air. It happened very quickly too. I looked to the jet end of the generator and by the time I looked back it was as good as over. If I ever do a similar thing again I'll pay much more attention to what is going on! Simon.
I sympathise, Simon. There is a precedent that's quite old involving blowing air through a heated burner and it was a Primus tool that features in a catalogue here from the Stove Ref Library Maybe even with your your compressor pressure regulated right down it was a lot more than would have passed through a burner linked up to that hand-pumped Primus device. I heat burners/generators up to red heat then blow through with an airline when they've cooled down to get rid of the debris dislodged by the heat - only because I've never bothered to rig up an airline to a burner being heated. Perhaps as well, from your experience! John
Yes, what's happened here is that the carbon burning off inside the generator (an exothermic reaction) has generated sufficient heat to melt the metal walls. C + O2 -> CO2 (and lots of heat!) The Primus idea worked on the same principle BUT the burner walls were thicker and the air-flow was much less and more controllable. Even so, I guess you'd have needed some training and been careful. Like John, I think the idea of the compressed air was to blow out the crap when the generator was cold; not when it was red-hot.
Simon, just my 2 cents research - carbon off - I buy it by the gallon. Available on internet, non-flammable and a 24 hour soak in this stuff releases and cleans every thing completely spotless. While considered pricy by some, the work it does and time and generators saved more than justifies the cost. If you can't find it, mail me your address to robertdrobert-812 county route 29 canton ny, 13617. I have even soaked an old cast iron fry pan with many years of carbonized grease embedded on it - 12 hours it was bare metal. I can find it for you and send you details if you're interested. Good luck ---bob
Nope, definitely air at the same time. Took me some searching to find it again but here it is. Link Link Now that it has happened it seems a very obvious risk, didn't occur to me before I did it though! A lesson learned. Bob, I've never seen carbon off anywhere in the UK. I'll have a look on the 'net and see what I can turn up. Simon.
Simon, should you not find it, send me a PT here. all gather all information for you and will ship to you as well, good luck---bob
Maybe, but what I got was not quite what I thought the warning was about. Anyway the stove is now up and running well with a new generator. Seems like they have changed the design at some point. The one I ruined had a removable jet, it's replacement doesn't. Simon.
Anyone ever seen a blacksmith forge? Burning charcoal and compressed (from a hand cranked blower) air will easily burn or melt steel. Brass will melt at a slightly lower temperature than steel.
I dabble in blacksmithing and run a charcoal forge... Yup, melted more than one nearly-finished blade tip... Diesel engines can do this to their exhaust stacks too, if enough soot builds up. The soot begins to burn in the stack, and can melt the whole pipe. J
