Hi This is my latest acquisition, a Burmos 21 that is going to take quite a bit of tender loving care to even get it fired up. Roughly in order that I will be attacking the catalog of issues: Firstly the pump did not resist moving in either direction when I got it. If the cup was leather it most certainly isn’t now. It’s so hard and fragile (falling to pieces) that replacement is unavoidable. It looks like the brass backing washer is not designed to slide up the shaft so I hope that the retaining nut is not swaged on to well. Otherwise this project will rapidly be a non-starter. Next the washers in the filler cap and travel cap both need replacing. The filler cap is the usual story of the rubber setting like concrete. The travel cap is an entirely different story. It’s fibrous! And was ready to fall apart! Never seen this before and wonder if it can be a help to dating this beast? I’ve got this as a user so there’s no room for sentimentality and I will be replacing it with one of Ross’ Viton ones BUT I am curious what it might have been made of. Assuming that these measures allow me to get some pressure I’ll then be checking out the quality of the rather coarse solder job on the top of the tank by pumping it up and looking for bubbles when it goes into a bucket of water. This will also tell me if the NRV is leaking. A quick squint down the pump tube makes me think this has never been removed so I’m hoping I won’t be adding to the statistics in one of the recent posts. That will move me on to the burner, clearly its not been used in quite some time judging by the cobwebs around the access screw in the top. Hoping it’s not seized but there should be no problem using a universal jointed tool to replace the jet. Finally (for now), the spirit cup is not something I’ve come across before. It’s not brass nor copper (as I have seen in the SRG) but steel (and rust). It’ll be easy enough to clean up but does anyone have any advice on keeping it from oxidizing again? Overall, I’m getting the picture that this was produced just after WWII due to all the unusual parts but does anyone have other ideas. best regards John
Get a grip! I mean, clamp the pump rod in a vice with some sort of packing between rod and jaws to maintain the grip but prevent scarring of the rod and take a close-fitting spanner to the pump washer retaining nut and it'll come off. I fear that post about Burmos manufacturing faults was mine, but fingers crossed that you'll be lucky and the non-return valve will come out ok and the pump tube won't have stress cracks or an end stop that's held on with just a whisker of solder. Wouldn't worry unduly about rusting of the steel primer cup. Plenty of use will keep it free of tin worm and you've said the stove's to be a 'user' ... That keeper cap washer's not unusual for that period 40's, 50's? I've come across that sort of composition before. The burner riser tube has a tapered thread to maintain a seal and I can't remember whether the keeper cap seals on a tapered screw also with the fibre washer to provide a resiliant stop to prevent overtightening. A nitrile or viton replacement would ensure the cap would stay leakproof anyway and would do (better) what the fibre washer did. Great set of photos and commentary by the way. Good luck! John
Thanks John, You were right that your's was one of the posts about Burmos manufacturing faults but I'm sure I saw another where someone was keeping score and Burmos didn't come out too well there either. Good idea about using a vice. Will be ordering some "soft jaws" to fit my bench vice soon so the pump shaft should survive unscathed. Better than using mole grips any day. The photos were taken with a small digital camera (still about 8 MP and has a reasonable macro facility) without worrying unduly about framing. The size limits for posting here mean that I can crop them (using Microsoft office picture editor) and then rescale them to about 640 x 480 pixels (using the attributes menu in Microsoft paint). This usually gives a jpg file of about 45 to 50 kB. Best regards John
Hi Blackjack, I vaguely remembered the result of roasting the flywheel for a small steam engine that I built after O levels about 30 years ago but I couldn't recall that it was oil quenching that blued it. Certainly sounds like it might be a good alternative to finding a suitable heat and solvent resistant paint. Do you have any suggestion which type of oil? (there are probably too many additives in a lot of engine oils these days) and should it be hot or cold? Best regards John
The type of oil used to quench the part is not really important. It could be cooking oil or any oil with a high flash point and in sufficient quantity that the oil doesn't catch fire when a part is quenched. Water can also be used or with certain methods (e.g. hot air gun), no quenching at all. The key to the process is that the part to be blued has to be very clean and polished and oil free. Then the part is heated and when the desired colour is achieved it is quenched in oil. All the oil does it stop the heating process instantly when the desired colour is reached. It is very easy to get the part too hot and go past "blue". If the happens the piece has to be polished back to bare metal and the process repeated. This is because the blue is actually the formation of an oxide layer on the metal. At exactly the right thickness this layer appears blue. Too much heat and the appearance is grey. The process of bluing is used a lot in clockmaking (another of my hobbies). If you are interested, this explains the process (for steel clock parts): http://www.bhi.co.uk/aHints/bluing.html Also a steel colour temperature chart: http://www.smex.net.au/reference/steelcolours.htm
