How does one tell if a 71 (whats the L on some prefixes? ) is of pre 1940 manufacture when say looking on taxavoidancebay? were they made of brass before or after ww2 or both? sorry if it's an sfq. blame it on the newbieness
I usually ask the seller if there is a Primus date code on the base . 71L - Most common version. In a tin with hinged lid and front flap. 71E - Forms a cooking system with one pot. 71K - Forms a cooking system with two pots. You can seen plenty of examples of the three versions in the Stove Reference Gallery. Terry
Some, maybe all, of the pre 1940 Primus 71 stoves had shorter tanks. The tin was a bit shorter also. They also had smaller flat topped fill caps. There weren't SRV caps until the early 50's so they have solder pins for over pressure, one on the bottom of the tank and one on top. I can imagine if one of those opened at tea time it would cause some excitement.
Ray, I may just be reading you wrong but I had gotten the impression that a single safety pin was continuous from top to bottom. The idea being that one of the two solder joints would fail if the fount swelled more than the pin could stretch. But hopefully the pin would not become a missile. I'll readily admit I could be wrong, but I believe that info came from one of our more knowledgeable members.
Hi Itchy, Thanks for clearing that up. I took a look at my 30's 71 and it does look like it could be one pin going from top to bottom. I've never had any stove reach over pressure conditions so in this case I mistakenly believed the over pressure would also have excess heat and the solder would melt and leak fuel that would ignite and flame up. Proves once again that I shouldn't assume. Thanks again for setting me straight. Cheers, Ray
ah I was thinking the indents on the bottom were repairs not this safety wire, thanks for the replies.
Hi, the pressure relief "wire" arrangement on old stoves and blowlamps is rather clever. The wire does indeed run from top to bottom of the tank but is secured with a high temperature braze on the tank base, and a lead/tin solder joint on the tank top. If the tank is over-pressurised, the tank will deform and push out the concave tank base. The rigid wire stays attached to the base and is pulled through the solder seal on the tank top, thereby releasing tank pressure. Best Regards, Kerophile.
so were pre 1940 tanks both brass and nickel? and the only way to really tell a date is the code? and I thought militaria was a pain to date....
Howdy, GJnord, I have a Primus 71, marked "AC" for 1938, that has a nickeled font. It also has the pin SRV setup, and is in need of a rework, it seems. A tiny pin flame comes out of the top of the pin, when I fire that one up. I wonder if those pins were solid, or hollow? Kerophile, any thoughts on that? I any case, yes, there were both nickel and brass fuel tanks pre-1940, from what I have seen. Take care, and God Bless! Every Good Wish, Doc
G,,day Doc . I have seen a cross section drawing of a Sievert blowtorch , from memory it was a hook brazed to the bottom of the tank , a solid wire with a slotted hole on the bottom of the wire to attach to the hook . don't trust my memory 100% cheers, Kerry oops , forgot to say , maybe the 71 is the same .
thanks for the gen Doc et al, if one bought a 71 and the wire had gone could a dodgy seller reshape the tank to look unblown? Also can they have the wire repaired if it had gone or is it end ex for further use? tar m
