Not long had this, and not sure if its Chinese or Indonesion made. It's in lovely condition, but I can't get the pressure very high hence the lack of brightness! The pump is very slack, even though the leather looks fine, so I'm hoping that using a pump adapter that I ordered for my Petromax will work ok.
@Johnny19 Nice lantern. Correct sized glass should be available from Base-Camp where you should be able to purchase a new pump leather (also available from Ross at The Fettle Box), try looking at Anchor/Magnalux or Petromax spares. Regards Jeremy
@Johnny19 Have you tried massaging some oil into the leather pump cup? Spread the cup a little whilst you soften the leather.
I haven't had the time yet to investigate it Fully. The petromax valve I tried on it is very tight fitting, so I didn't want to force it. I think it must be the NRV as it is slack sometimes and you can get a half pump in other times. Oh just checked, and its Steel!
I'd say that's an Indonesian Butterfly, not China. The Chinese ones have a different look. Its quite a recently-made unit too. The older ones were made of brass. I have a couple of these steel ones too. Overall, they're fine except for the pump performance. I had to mod the leather assemblies to get them to work better. Another note: the plastic material of the pricker wheel and pump knobs are no longer what they used to be. Unlike the older ones which were thermosetting phenolics similar to bakelike, these newer ones are not very resistant to high temperatures. They are not solvent resistant too. Acetone or any paint thinners containing the usual toluene, xylene, etc would soften or dissolve them. I had since replaced them with the older Butterfly spare parts.
I've made a start anyway, ordering the correct glass from Germany (Schott Suprax), which after shopping around worked out the cheapest including free shipping. The glass seems to be a brand for any of the Petromax type lamps as I didn't really want to stick a branded petromax one in it! Next job will be the NRV, and getting hold of a spares kit. One added bonus is the glass already in it is an exact fit for my W&B M1. Glad I spotted that lamp, as I was in two minds about it, but went with my instincts which are usually spot on.
There's one thing I do like about steel founts. They're considerably stronger than their brass counterparts. On my steel Butterfly, I would not hesitate much on pumping it to whatever the built-in pump could deliver. Just for the test, I gave it the full brute with not just my fingers but my palm, all muscles and weight directed on the pump knob. I managed to get it to register a little beyond 60psi (~4kgf/cm2) on the gauge for a fair number of times. Not the slightest bulging on the fount or its bottom was detected. It did burn a little brighter than normal but a lot louder. It was guzzling more kero than justifiable for its light output anyway. However, that was just a trial to satisfy my curiousity. No real or practical reasons for it to operate at such high pressures. The generator would not last very long if its continuously operated at this pressure level.
@MYN , yes I can manage to get some pressure in, and as you can see by the pics it's ok when lit, but it could be brighter! I just don't want to be pumping it for 20 minutes to get a decent lighting pressure, so I will have to check out the Valve soon, as I want to take it on a camp next month to Cornwall!
On the average unit with a properly working pump, I think you'd only need 50-60 strokes on a full tank for the filler cap gauge to register 30psi, ~2bar or roughly the 'red line'.
@Johnny19 I very much doubt that the problem lies with the valve, if it's loose or faulty, either you wouldn't get any pressure in the tank at all or if you did, fuel would come back up the pump tube. If you can get some pressure into the tank, I suspect it's the pump that's at fault. Have you tried @ROBBO55 's suggestions ? There's no harm in checking the valve but you can get away with replacing the rubber pip. Henry.
The real problem was actually some came with the o-ring type plastic pistons. They're not exactly well made and I just couldn't feel the usual snug in the pump tube. Perhaps the tube wall had some irregularities. I mod part of the piston to accomodate a leather cup, which was far more forgiving and thus more efficient.
@MYN Fixed (sort of), yes the problem was indeed the leather cup and the fixing (see photos). The cup brass was very loose on the rod and I need to dig out a couple of washers to pack it out tighter. In the meantime I put on a Hipolito pump (slightly bent), and it pumps up beautifully now! I would still rather use the original pump though, when i can get some parts together. For some reason there were 2 springs on this pump, don't know why, but at least we know its not the NRV now!
The brass part of the piston where the leather attaches should actually move up and down the rod end while you pump. It should have a little tapered hole which should seal up against the tapered part of the rod on the 'push' stroke of the pump. Sometimes, the taper might be a little rough and leaky. This could easily be fixed. On the pull/drawing stroke, the piston moves down and is arrested by the nut at the end of the pump rod. Some air is drawn in through the hole to fill up the pump tube. Its the leather that should always be seal-snug with the pump tube inner wall. Sometimes, some heavier lubricating oil or even grease improves the pump performance simply by making the leather seal better.
@MYN Thanks again, at least I'm in the right ballpark now, getting there slowly. Need some more free time!
This is my experience as well. I checked tke calibration on some gauges, by closing it on my compressor at 2 Bar. The gauges varied between 1,5 and 2, 5 Bar. Some didn't register any pressure. By bending the spiral spring inside, for it to have about "zero force" to start moving, I managed to it to register pressure. These gauges are not accurate!
