A Primus 70 L, brass, unregulated. Her date of manufacture is 1931 , based on the following. No safety pin, so 1926 - 1931 Recessed filler neck with patent stamping: 1931-1934 Stove is complete and in good used condition, tin is fair. No pricker or instructions. Colorful front panel with spotty surface rust. Top lid's slot for front panel's little clip helps keep the tin closed for packing. Fount side stamping include PRIMUS No 70. No stamping on burner plate or bell. TRADE MARK PRI-MUS with lit domestic stove logo BENZINE BENZOLINE along her upper edge. Flat-topped, edge knurled fuel cap stamped PRIMUS inside an oval. NAPTHA PETROL opposite side, looped brass handle with chain hole topside close to fount. PATENT SV.No48624. framing the spirit dish on fount. ENG.No171536.. The aforementioned Patent number refers to the recessed area on the fount framing the filler neck. Used to prevent overfilling, leaves a volume of air between top inside of fuel tank to lower filler neck. Little brass spirit cup, standard for most Primus 70 (exception: regulated Primus 70's). Brass travelling cap had no gasket when I received the stove. Assuming the original was cork, I cut a Viton (1/16th") equivalent. Burner bell with one hole along her extended neck. Fount cap's cork gasket was still pliable, good size and condition, held pressure so it was retained. No markings on bottom of stove's fount, top of case showing wear from heat/use/elements/age. Bottom of case with 4 dimpled feet with each offset outward. Tin with heat shield, but does not have the extra ventilation holes found in more recent version(s). Some of her original silver finish still visible inside top lid. Case had surface rust, most was removed with 0000 and WD 40, but this process also removes some of the original finish. Stove deployed in her 'operating' state. Burner bell removed, travelling cap enabled for packing: Side of case with English instructions, showing heat and rust damage upper 1/2. Opposite side with other languages (for more info, an identical tin is shown with this 1926 < 1931 Primus 70 ). Fuel cap gasket held pressure, half filled with Coleman Fuel, stove being primed with Methyl Hydrate Initial low-intensity burn with decent blue color. After a minute she was burning well with the expected audio thrumming and high flame intensity. Avoided using her flimsy and heat-sensitive tin, placed in the more robust Primus 71 E (early model) kit insert for boiling up water. The Primus 70, unregulated versions, suffer from a number of deficiencies and are really only practical for boiling up water. They are wasteful on fuel: once extinguished fuel vapor will continue to exahust from the jet and/or the fuel cap once it is opened to relieve pressure; due to filler neck size (very narrow) spillage risk increases even with the use of small funnel. These can be a challenge to extinguish as they have to be physically blown out and often this means your head/mouth is very close to the combustion area (burner bell). They have a small fuel volume that results in short burn times, frequent fillings and increased risk of scorching wick. They are slow to pack up: the burner bell has to be cooled before removing in order for the travelling cap to be screwed over jet so no fuel leakage occurs. Their tins are very flimsy and can only support small volume and diameter pots; their colorful heat and rust sensitive graphics easily spoiled. The 70's also support the Primus No. 4200 silent damper, shown with a regulated Primus 70 , however being unregulated they will only run on high which increases: the risk of underburn; an inconsistent flame pattern; and/or a 'stuck' lower half of the silent damper to the burner bell during operation. They are however easier to extinguish with the silent damper deployed. Overall imo this stove should only appeal to collectors as the precursor of the much improved regulated 7x line of stoves. They are not one I can recommend be taken on any field trip for practical use, there are far better, safer, more robust options available for the solo/small group traveller(s).
Thank you for a nice, thorough " rewiew" . Appreciate your description of, and attention to the details. And your conclusion on the usability of the stove is very helpful. Best regards Stoveuser
Hi SMolson, a outstanding documented post the pictures and tutorial is as all ways first class. The 70 really is a totally beautiful stove, the tank design and the engraved lettering is stunning, the soldering fixing the handle to the tank is perfectly done. I have viewed and admired the 70 on here and seeing one being lit on Youtube, but never took too much notice of how beautiful a stove the 70 is. I think the reason being your one is polished but not over shined, which really makes the engraving stand out. Well done there on a superb addition.
Thank you for the kind comments. lol Ian. I noticed one of my images (7th) was duplicated, it was meant to show this one, with the remaining Patent info: ENG.No171536. This one's burner plate was solidly affixed to the bell, so when testing with a silent damper I used a spare from another 70, one whose plate was removable. That's one reason why so many of these types (Primus 70, 71; Optimus 8/8r, 80, 99; Svea 123/123r; Radius 42, 46, etc) are seen and sold without them - easy to lose once removed. I agree Mr. Optimus - this version of the No. 70 is likely the most 'decorative' within its model line: presence of patent info, design implementations (recessed filler neck) + lack of extra (2x) soldering due to absence of SRV pin. They are extremely simple/basic to operate and maintain. Overall a very cute little stove.
OLD THREAD, a reference post. My thanks to @SMolson a well respected appreciated current subscriber we've not heard much from in years. He and family cook with his kero brassies daily as I understood it. His ref. posts are excellent presentations, content rich, enlightening and reliable. As member he is a real stand out for the excellent content he has contributed to our site . I am however inspired to post to make Pr 70 clarifications. Re his "Recessed filler neck with patent stamping: 1931-1934" Note: Re SV.No48624 is Swedish Pat: Sep. 16, 1919. and "British patent, GB171536, from 1920" source SMolson's stove, with (straight-up) pat'd. recessed filler neck, is depicted in 1925 catalog. Image in c1927-29 conrup catalog gives me impression, straight-up filler tube has ended by this time? Seems to me one on right is not straight-up. One on left a re-used image from 1925 catalog. I ended my comment w/ "?" above. I am not certain re year range for his stove but I am certain that it is earlier than 1931-34. Re ""No safety pin, so 1926 - 1931"... that's close enough. While I'm here, technically, pin was added to the 70 during 1931, and again it seems stove in OP was offered in 1925 catalog. my thanks again, I continue to learn from SM ref. posts btw, respectfully omc tag @Spiritburner views 2,925
