I am aware that this is due to repeated over pressuring and I'm sure my question has probably been asked many times so apologies..but has anyone successfully presssed back the base?
@paparazi The best advice is that once ballooned these tanks are inherently weakened and potentially unsafe. The reason is that the process of ballooning out the bottom tears the internal soldered seam of the base plate. I was given this advice when I joined here some years ago. Best regards Tony
@paparazi As Tony said. Pushing the base back in would be the easy part. The joint would have to be cleaned and re soldered. I haven't No tried it but I suppose it's not impossible .
Yes I can understand why that would be the case. So repairing this properly would be beyond the tooling capabilities of all but a suitably equipt specialist? Has anyone on here done this?
In my opinion, it's better to find another lantern which has a sound tank and to use the knackered lantern for parts.
You did swear.... naked Fonts / Tanks do appear on auction sites, find one and swap all the parts across
Cost me just over £6 and it has a good glass and top so it doesn't owe me anything..into the spares box she goes.
When you’re feeling creative, cut the ballooned bottom out and make a (side) reflector for a lantern. Cheers Tony
Has anyone tried filling the font completely with fine sand and masking taping the holes up. Flipping it over to sit in a bucket of sand so it is well supported and begin tapping the bottom with a wooden dolly. Take a bit of sand out and repeat till it's flat. Empty it out and run a blow torch around the seam bit by bit heating enough so that you can melt some extra solder. Worth a go if it's a throw away as is??
Given that the seam is probably knackered, and that it's not a simple seam to solder, the safest bet is to pick up a replacement tank - they are pretty easy to come by. These tanks operate at about 28psi, which equates to about 1 tonne of force on the bottom plate. Cheers Tony
Playing devils advocate here but, the bottom is also held in with a fold so impossible to just burst off! I would imagine it would just leak, which is easily tested on a non lit lamp. I'm only saying! Martin
Martin It doesn’t matter if it leaks while the lamp is not burning. Kerosene is much safer to play with than gasoline. But, if you do a bit of research here, you will see that Tilley lamps have become fireballs and have caused injury injury. This is a public site. While experienced fettlers will be able to make judgements based on experience and knowledge, many new members may not. I would never advise a newcomer to bash the bottom of a bulged Tilley tank. That was the advice given me quite some time ago by those who knew much more than me. Tony @paparazi
Bloody hell, those pictures speak volumes. They would be very useful to new and old fettlers just as a reminder. As a retired engineer I run the figures, the lamps run at or around 25psi or 172Pa on the fount base approx 10 inches or 25.4cm diameter giving an area of 78.4 sq in or 708.6 sq cms that equates to a force of 2000 lbf or 907kgf. That’s a lot of force, 2000lbs or 910kgs will further stress any joint. So the result could be a leak of fuel at worst a burst along the seem. After looking at the calculations, for my money, bulged lamp fount bottom now equates to get a replacement fount. Cheers Pete
Actually 2 atmospheres / Bar so ~29.4 psi (I've no idea what that is in Pascals) thus even more force than you calculated, Pete, and that's at normal running pressure. But we're talking about situations where folk unthinkingly increase the pressure even further in a misguided attempt to compensate for a vapouriser that's beyond it's working life. Therefore the bulged base and torn seam...
All I can say is WOW.... what the hell were they thinking? they wouldn't have been able to sit it on the base without it rocking.
What Tilley were thinking about was maximising their profits by minimising their costs and to hell with the consequences. This was actually a successful strategy because they were such a well known brand that people continued to buy their products despite there being a far better lantern available which wasn't a household name i.e. Bialaddin / Vapalux...
This was, of course, after Tilley changed the configuration of the tank and base plate from the earlier incarnations of the Tilley X246. What year was that, David? Tony
Thanks, Neil. I’ve only ever seen one X246 (late 50’s) with a bulged bottom, but plenty of X246Bs. Cheers Tony
I’ve only seen X246Bs with a bulged or as I call it “blown” bottom. No doubt there could be others but the “Bs” are definitely prone to being “blown”. Cheers Pete
That's just the sort of thing that can lead to what we ecologists know as a 'bog burst' - shetland bog burst - Jeff may be able to tell us more. Anyway, to answer the original question:- In my early days (before I knew what had gone on with the solder seam inside the tank), I tried to remedy a bulged tank so that it, at least, sat square on the rim rather than the bulged centre. I cut a circle of wood large enough to sit just within the base rim. Hammering on that as hard as I could with increasingly bigger hammers produced absolutely no flattening effect whatsoever. Clearly the force of the hammer-blows distributed over the entire area of the base reduced the pressure to something insufficient to have any effect - this is simple physics; P=F/A. I suppose you could use a more powerful press but then you'd have to devise some means of pressing against the topside of the tank without it being deformed. But it's all academic anyway because once the base is bulged, the solder seam is irreparably damaged and the tank is scrap...
Yes, subsequent to the Tilley family selling the company to outsiders, who, as you've been known to comment, sacked their last engineer and replaced him with an accountant...
Yeah nearly got me into trouble that one. Many years ago I gave a talk on pressure lamps to an OAP group in Leighton Buzzard and was taken to task over things like that and what right did I have to call myself Doctor Tilley by a young lady in the audience. That was Cherril Fred's grandaughter and for a few minutes afterwards I remember the discussion got quite lively. All ended peacefully though as that was accepted as a joke and I pointed out the sweatshirt said Tilley Doctor not Doctor Tilley. I tend to wing it with speechifying so the chances of foot in mouth tend to be quite high. ::Neil::
This type of soldered + folded seam is quite prone to giving way as shown in the photos by @Henry Plews . Its not only found on the later Tilleys but also on others like the Petromax and clones. The subsequent result would be blown bottoms. Its might not only be due to an inherent design weakness but also the way and the quality of soldering. If it was not perfectly done during manufacture, it'll be a near irrepairable defect. Its definitely not easy to reflow the solder properly to wet all internal surfaces with the seam already folded. Or shall I say near impossible. A flattened bottom would quickly re-bulge once the fount is re-pressurized. That's due to the internal solder voids on the joint.
