Hello gents, I found an example of what is probably a blown tank on a Primus model 5 from 1946 so have included a photo of the subject stove below. At first it looked to me like the filler neck was pushed down in, but I now think it resisted deformation and the rest of the top of the tank suffered the same fate as the one George has shown us and bulged upward. It's a shame, for aside from the lift or bulging, it was a nice stove. Regards, Doug
Hi Doug, thanks for reporting this observation and including the photo. I see that your stove is actually a Primus 5S, which like my two "blown" Primus stoves, is one of the "Senior" models with the lighter gauge brass used for the tank. It appears that they are more susceptible to ballooning than the "original" two-pint models like the 1 and 5. Like you I noted the slightly irregular distortion of the tank. You mention the stronger area adjacent to the filler upstand, which resisted upwards movement. On a smaller scale I see that each individual letter of the tank engraving sits slightly lower than the surrounding brass. I think that this is due to the local work hardening of the brass when the lettering was impressed on the tank. This has made them slightly harder and stronger than the rest of the tank material. I think I have seen ballooning on a Primus 4, 1.5 pint brass tank stove, but never in the 1 and 0.5 pint models. I guess they are proportionally stronger for their size. Aren't stoves fascinating? Best Regards, George.
No one has mentioned if the riser tube in the tank is up off the bottom. Is it in these blown tanks or is everything as it should be. Inquireing minds want to know. lance
Hi Lance, You might have seen the following statement in my earlier post: "You will note that the top of the tank appears to sit considerably higher in the curvaceous stove. I took measurements and whereas the "normal" 1S:or is 100mm from the ground at the highest point on the tank, the curvaceous one is 110mm." Because the stove operates well, the internal plumbing must still be intact. It follows that if the lid lifted by 10 mm the bottom of the dip leg must have risen by the same amount. I was too lazy to measure paraffin volumes, on work out a way to look into the inside of the tank without owning an introscope.... I hope this answers your question. Best Regards, Kerophile.
Hmm I got a optimus 45 which appears to have gotten a middle age spread in it too. Seeing it was made around the early 60's I think. Wondered what all this "lovely discus " stuff was about. Till I fired it up and found I had about 80ml or so left in the tank when empty. The gap I measured roughly to be 16mm from the bottom to the pick up tube. Made a insertion tube and fixed that up. Now only 6 ml when empty. Only need a travel cap and jet for it now!!! I was surprised the oxidized lead seal still works..Changed the nitrile washers in it and it fired up niceish. Also got a 210 with the same problem but I ended up just banging the top down a bit to close the gap.( 'ol beater of a thing) Just a thought but both these stoves have at some stange been dropped or the wanged on something which has left a bit of a ding. Maybe some one has reafed up on the riser to pull it back into place or used a air compessor in an effort to blow out the dings. .Who knows. Cheers Hope it some use Bruce Another from my collectioin ...mostly non original anything much collector
Sorry mate i was thinking of an internal mesurement not from the outside as i thought your mesurement was taken. It's cleared up though as Bruce has defined the difference. Thanks much for your clairfication. lance
I like to browse through different museum homepages. You never know what to find, and when I ran into this little picture I immediately came to think about Kerophiles old thread about bulgy tanks for some reason! Link Now that's curvaceous It's supposed to be a Svea No5... Christer
What the hell!!! What do you (not) have to do to get that with a kero burner? Not that I wish to duplicate it though... holding a coleman 550b fireball was more than I wish to experience with a stove
What the hell, indeed! I have no idea how to succed with a thing like this. The brief text at the museum only says that it exploded and ruptured the soldering, nothing more. Funny thing since Svea in the old catalogue to be found on this site very proudly announced how good and "absolutley reliable" their 'double soldered' bottoms were... Christer
. . .I suspect compressed air jiggery pokery at work here, it would be mighty difficult to pump it up that far by hand
