Hi. I recently overhauled the NRV on my Primus 96, (1931 vintage), and was unable to locate the old sealing washer around the valve. I had a good look down the pump tube with a torch/flashlight but nothing was found. I’m guessing that the valve assembly hasn’t been replaced since production? And all I could see was a leather/grease/oil mix The valve pip looks to be made from cork. Does anyone know if these stoves left the factory without any form of seal?
The cork is very likely the original, give it a soak in oil and there is a good chance you'll get a few more decades service from it. If it doesn't seal, you can reverse it. A lot of older No.96s seem to have left the factory without a sealing washer for the pump valve body. And a lot of stoves which did were reassembled without one after overhaul. Reassemble with a lead or HDPE washer and a smear of copper grease on the threads and you shouldn't have any problems now or in years to come.
Thanks @Blackdog I used a “viton” pip and an HDPE seal from Fettlebox. Had visions of struggling with a stuck NRV so relieved to hear loud click upon release. Alas original cork pip was damaged by me removing it with a pin. regards Nick
Commiseration @Sizzler670- Viton does the job perfectly but it's always depressing when the original cork can't be salvaged. Well, I think so!
Well @Blackdog, I guess it makes the stove less original….but then again I was having an issue with paraffin/kerosene leaking into the storage box and I didn’t want to have to mop up every time I took the stove out regards Nick
Yes reliability is key. It's amazing really how cork often can be revived and reused on a stove where all the rubber seals hardened decades ago. A true wonder material!
I’m thinking of a way to remove most/all of the solder repair mess from around the filler neck without disturbing the patina too much.
Top tip, if you can, carefully swap the cork NRV seal around so the "fresh" face points towards the seat. Old cork is the very best seal for these As mentioned. from the factory there is often no seal between the body and the pump tube, just metal-to-metal. I always refit a seal so theres less chance of twisting the pump tube/bottom fitting off if you need to go in again... Alec.
Best looking cork I have seen. I wish I could source such fine cork. The ones from grog nowadays seam total crap. I just played with a Primus 96 and it had no seal either. I think it is from the 50’s so not old by any means. I had to de - solder the pump tube and base out to undo the NRV
Many in my collection had no washer under the NRV. Flipping the cork usually doesn't work either for me, although many had a cork pip. Takes a NRV tool that does not rise off of the NRV, I had a special tool made that screws on to the pump tube to prevent it from rising off of the NRV head. A few have said they never had an issue, they likely didn't have dozens of the 96's to work on. Duane
Excess solder can be a pain to get rid off. Here is what I do: Either re-melt the solder if it is really thick, and then wire brush when the solder is molten. This shifts everything except what is in the joint. Once the stove has cooled down again you have only a very thin solder/brass interface coating to deal with. Or, buy youself one of those one-inch wide Skartsen scrapers that are used by painters for removing stubborn old paint and coatings. We have them in boatshops. This is basically a handle with a screwed on replaceable steel blade, which cuts on both the push and pull strokes. With this tool it is possible to shave-off solder deposits, and even the brass tank if you are not careful!!! It is very accurate and controllable. You can then use very fine (600-1000 grit) wet-and-dry abrasive sheet to remove any final traces of solder. Here endeth the lesson. Best Regards, Kerophile.
Thank you for your valued advice @kerophile @hikerduane and everyone else for your input. Regards Nick
