Nice unpolished and unmolested No.30 with decent patina and now a reassembled original cast pan ring. Finally brought back to life with new set of seals almost all round (have yet to find a good match for the seal inside base of the stubby pressure release). Other than the still leaky pressure release seal, the main remaining dilemma is whether to do anything more with the pan ring. There is still a gap where one fragment has been lost. But filling the gap with new weld, then grinding to shape, would run the risk of causing more problems than might be solved. Argon arc MIG with stainless filler wire is the most viable type of weld on this fragile type of casting, but filling, as opposed to 'simply' joining breaks, runs even higher risks of major meltdown and/or new stress fractures elsewhere in the ring if cooling is too rapid. The balance point between joint failure due to lack of penetration and complete blow-out is very narrow on this material!
As long as the pan ring is doing it's job why bother with replacing a relatively small bit of it? If you were going to polish it up and restore it to showroom condition it might be another matter but as it stands there's not much wrong with keeping it in its present condition. The other 5 radial supports are intact so there's no risk of a pot falling through the centre. Just MHO. John
I think you answered your own question there. I haven't looked hard enough yet to see the part that's missing but for display, I think I'd be attempting some sort of repair with JBWeld or whatever. For use, just put on another pan ring. I'm sure Ross will be able to produce a seal for the pressure release if you ask him...
Should have done a sequence of photos to show sorting the cast ring. Too late now, but here is similar ring from my pre-WW1 Optimus 5 which have been working on at same time. This ring had ended up as 3 separate fragments lying in bottom of a tray waiting for whenever. Just got idea of an 'in progress' photo in time. So here is underside with 5 visible weld points before painting: The one on the '30' above looked the same at this stage - amazing what a catalogue of sins Clearview heat resistant stove paint can hide!
Here, I would have used a nickel silver brazing rod to repair and fill in the missing gaps as needed, after doing a preheat to 500 deg F in the oven, and using the oven to gradually cool the repairs to stress relieve the work as a whole. Much like repairing cast iron engine blocks, except for studding the crack. Murph
@igh371 I am about to embark on the Fettling of a 1921 Primus No. 30. What was the issue with your leaking pressure release, and how did you solve it? Mine looks a wee bit dodgy. Cheers Tony
@Tony Press Hi Tony, the issue above was simply one of sourcing the right size of rubber wiring grommet to cut to make a viable replacement for the age hardened seal on the release screw. Nothing very dramatic. But looking at the release screw on your 1921 link photo I'm not sure that the two are exactly the same anyway. Ian.
Gave the little chap a freshen up today New pump cup required, the old one had finally gone to atoms! Viton o-ring fitted under the air release screw, previous one had gone hard over time and it was a menace to get to seal. I don't think the pvc grommet and oil vapour agreed over the past few years A good clean-up and a thorough rub over/buff up with machine oil and the job's a good 'un. Good for another few years use again Alec.
Nicely done Alec, very sympathetic treatment of a lovely little stove, and a good pairing with your '34' too. Ian @Rangie
