Primus 391 - alcohol burning lantern
It was high time to fix this lamp.
It's my first alcohol-burning lantern to fettle with - Primus 391. Photo above shows her in finished condition.
The lanterns is from 1945 if I decode the stamp properly: AJ8
Of course it was not always like that - this morning she looked little more miserable.
As the lamp came without jet I've decided to refurbish her back to original configuration - for burning alcohol.
Air-tube end (the one which hides in the collar) was partially crushed, probably to restrict air flow in alcohol config. I've repaired the tube and planned to turn brass component, similar to what Morgan is showing here: 1952 - Primus no 1321 för sprit (alcohol)
However - as a quick fix, before I'm back in my factory's shop - I took old nut of proper size and shaped it by hand into matching form.
I had no idea how small the opening should be so I took this guess. Turned out to be perfect.
Thanks to Nils I know now that the opening should be of 3,5mm diameter.
Second missing part was small mesh disc which Nils mentions in this thread: 1952 - Primus no 1321 för sprit (alcohol)
I've punched it from one of these ugly, plastic funnels we get with our lamps.
Mounted on pricker rod.
Last missing part (I hope) was box nut which seals the whole assembly.
I don't have any Primus donors laying around so I took it from Optimus spare parts. It almost fits, I needed to cut graphite sealer a bit and tape threads with Teflon tape - Optimus thread is not the same as used on this Primus. With this primitive but invisible fix I managed to seal the assembly.
To save Primus original globe I run test with expendable Petromax glass. Forming new 200 CP mantle shown below.
After the new mantle was pre-burned I re-assembled the lantern with original globe.
The light output from this tiny lantern is exceeding all my expectations!
My so-far best small lantern, Optimus 930, is falling on Place 2 now.
Especially that it's rated on 300 CP.
This tiny Primus 391 is brighter than Optimus 200/1200 in my collection!
No renovation is complete without field tests. After all - these are tools, not just art pieces.
Obligatory walk through the woods, to check post. Moderate wind and no rain - perfect for lantern test.
Light output is outstanding!
Heat production also.
After tests I can say that Primus 391 feels best indoors or in shielded areas. At least my lamp.
With night breeze the lantern flickered and I needed to adjust its position towards the wind, to keep the light.
It is a perfect tent or boat lantern - especially due to lack of kerosene fumes on start/finish. Especially on boats, where many use alcohol stoves, this lamp would make sense. Noise level is moderate, not as noisy as Optimus 1551 but still far from Primus 981.
Below is a "family shot" showing different Primus lamps side by side.
I post it because I lacked such comparison when I was looking for field lanterns some time ago.
Standing on the bench, from the left, are 2x Optimus 930, lighted lamp is Primus 391. To the right of it is Primus 981 and Primus 1020.
Hanging behind is the mother of them all: Primus 1001.
Monstrosity on far left is Optimus 1550.