Greetings All. Having used and enjoyed my Optimus 1200M over the past year or so with solid performance, I experienced something new. After trying a vintage Coleman Silk Lite Gold mantle from a pack I acquired at the thrift shop (wasn't impressed, light seemed dim and very yellow) I installed a Peerless 111, the usual mantle I use. After burning it off and just a couple of minutes into lighting, the whole nozzle assembly, both metal and ceramic bit, blew off the vaporizer. After cooling, I found the ceramic to metal connection snug, but when tried the metal to vapo connection was quite sloppy and even slipped over a couple of threads when I re-installed. I tried to tighten down and light again with a junk test mantle. Same thing happened, after a couple of minutes and additional pressure, the whole thing blew off the vapo tube. I have experienced the ceramic nozzle backing off and falling off if unchecked for awhile, but never this. Has anyone else experienced this? What would anyone recommend?
I don't know the "build" of the Optimus, but I suspect differential expansion between a worn metal to ceramic connection could be a problem. However someone on the site will have had real world experience with this problem and a "fix" for it.
It certainly sounds like the thread between the mixing tube and the gas chamber (I think that is what it is called) has been burnt away. This is not uncommon on old lamps, but a 1200m is relatively new. A 'fix' could be to find a tapered steel rod of the right size and expand the mixing tube end until the thread is tight. A good tight fit, and hopefully gas tight, is needed there.
Optimus are among the best lamps of this design in my opinion. That can be that an earlier owner or in manufacture, the gas chamber has been over tightened with damage to the tread as a result and after avail it will fell off. Recently I helped a friend of mine to fettle a near new Santrax 150cp lamp where I found the tread on the mixing tube to be in the same state as yours. Probably over tightened in manufacture. Nils give you a good way of fixing the problem I will think. Michael
Thanks for the replies. I'm fearful I would split the mixing tube if I tried to expand it. It does glow orange during use, does the heat of use anneal the tube and make it soft enough for such actions? I'll take a picture or two in the daylight, I think the problem has to do with the threads on the female nozzle base than the vaporizer tube that it screws onto.
It is easy to anneal the tube if needed, but we are not talking about much expansion at all. Even though the threads are better on the tube, it is easier to expand that rather than make the chamber smaller.
Just being heated to orange does not anneal brass. To anneal it you need to heat to dull red and then quench in cold water. Once you do that it will be possible to drift it out slightly with a tapered rod and it should not split. ::Neil::
Actually brass don't need the quenching bit to get soft. That's mainly needed for treating steel and related metals. There is no difference between letting brass cool slowly compared to letting it cool quickly with e.g. water when it comes to making it soft. It will be pretty much the same result regardless which method you use. Heat is the only important thing here. And perhaps the length of the period it's beeing heated? But it's of course often more practical to toss it in water in order to be able to handle the things immediately.
Close up of the vaporisor. It looks like the threads have no peaks on them anymore. I don't know if I ever unscrewed this part from the other, so I don't know when wear could have occurred.
It should be possible to get a helicoil for this one if there is enough material around. A single one dont cost much and they are used by automechanics often. Claus C
I don't think these parts are actually worn. It looks to me like they have been that way from the beginning. Probably a manufacturing fault that wasn't caught in quality control. By the time the 1200M was being made it was getting close to the end of Optimus making things themselves. Maybe they were getting careless. I still think the best option would be to expand the tube a bit or maybe copper tape.
I like the idea of trying the copper tape. I haven't found any without adhesive, but I suppose I could take it off with a solvent first. Thank you for the ideas. I will report findings as events warrant. Jimmy
Gneiss and Nils, brilliant! I received the 1/2 inch wide copper tape I ordered from a stained glass outfit today. I cut a strip, cleaned off the adhesive, and wrapped it around the vaporizer threads. The mix chamber female threads gained very good purchase as I screwed it on and had no play when turned on snug. I lit it and burned it for a while and all remained intact. I now have 8 yards 10 inches of copper tape left to share if anyone has a need. Many thanks. Jim in Milwaukee
Good to hear it worked. It's not something I would have thought of myself. I'll be interested to hear about the long term results.
I agree with Nils, reckon those threads were made that way Copper tape aye sounds like something I should have handy
