Hi fellow members. I am just about to refurbish another 1971 tilley lamp but I have slight concerns on the bottom of the fount. It could have been over pressured in the past or it could have been soldered like that from new ? I have stripped the paint as it was a bit on the worn side and I would like to give it a new colour. It is sitting level on flat surfaces and does not leak pressure. As you can see from the pictures the base seem to be nearer the bottom than the other side. Any more experienced users comments would be appreciated before continuing. Thank you in advance.
It does look like it has been overpresured - or is the rim dented inwards ? - I would do a dunk test to see if it leaks. Although these fonts are not hard to come by - you could pick up another rusty donor lamp ?
Hello Thank you for the advice. I did a dunk test with 40 pumps to pressurise. It was OK with no visible air bubbles. The rim looks to be good on it and not damaged in any way. I also placed a steel rule across the bottom rim and moving it around the circumference of the bottom edge. There is very little clearance at one point but I may have to live with it. I am not sure if I can get enough heat at that point without damaging the solder and just put a bit of a tap on it to go back in shape. I may have to live with it as long as it does not fail at a later date. Thanks again.
I would go higher on the pressure. Some here will go up to 100 but 60 is a good working pressure for a X246b. I would be reluctant to use it indoors just in case it lets go. On the other hand - you have done the cleaning up so all you are risking is your time and some paint. Another tank will come along sometime.
Thanks once again for your time to reply. I may try a hot air gun and a rubber mallet just to see if I could get a bit of movement. I never usually pressure any of my lamps more than 60 strokes as I thought that to be the required amount as per the old operating instructions. As you say at the worst it may be a case of time lost on the paint but until I feel a bit brighter I will leave the spraying.Thank you once again Fireexit1
I wouldn't bother heating and hammering the base. It might work but the I reckon the chances of success are slim at best and you might introduce stress cracks. If it works I'd use it as it is and wait for a better tank to turn up.
Thank you. It is hard for me to consider not using it with out some form of remedy or using as is I am a user opposed to shelf queens . The rest of the tank is completely ding free. Thank you for your comments.
Good Morning Colin. Thanks for the reply. I am considering using it as is. The tank is in very good order apart from that over pressuring look about it. At the worst it is time, paint and a bit of dissapointment at the end of it. I have another first class fount but the paint is perfect on that. Alas it is another red fount that I was going to rebuild. This fount was going to be sprayed either Nato Green or Copper similar to the original Tilley colour copper. Still making my mind up for colour scheme and getting over a virus so not up to spraying at the moment.
Not here to disagree re shelf queens. I like to have all my stuff eventually working too. I have even restored a fount a bit like yours with a complete resolder but I had a less blown out base to work with. Perhaps you can get some light into the fount to see the condition of the solder seam. These inspection units are a lot more common and sometimes gun owners have them. Worth a few minutes reading is the following post and the mentioned post within it, concerning a FL6 explosion. The condition of the seams is strongly discussed and the FL6 failure is also thought provoking for owners of pressure devices. Good luck however you proceed. Tilley x246 with a wobble
Sedgman. Thank you for your remarks which I found very useful and certainly a pause for thought. I have looked at the links you sent to some very interesting scenarios concerning this. Thank you once again for taking the time to point these very useful and interesting points to take on board.
Just something to consider @Steptoe Tank Pressure - Applied Force Understanding that when the 7.5” or 19cm based fount is pumped up to 2 bar, 29psi or 200kPa, working pressure there is a pressure force of over 1300lbs or 580kgs exerted on the base. Any flat plate surface will flex or bulge with this force. A lamp that operates with the fount’s base pressure of around 1300lbs force, or 580kgs, a fount full of fuel and flame on top all contained by a stretched and distorted weakened seam or base ........ what could go wrong? The question is how much? I would gauge it acceptable if the lamp sits on a flat surface without rocking on the bulge. As soon as there is evidence of the bulge causing the lamp to rock or when turning the lamp over and seeing scuff marks on the base caused by over bulging ...... I would deem it “blown” and condemn the afflicted fount. Here is the actual calculation that was used to calculate the applied force to the base of a typical lantern: Pressure = Force/Area Force = Pressure x Area Area of the lantern’s base plate. Fount base diameter of 7.5in - 19cm, with a pressure of 2Bar - 29psi - 200kPa Area = π (Pi) times the Radius squared: A = π r2 or, when using the Diameter: π/4 times the diameter squared: A = (π/4) × D2 Area in imperial units. A = 3.143 x 3.75 x 3.75 A = 44.2 Sq ins Area calculated in metric units. A = 3.143 x 9.5 x 9.5 A = 283.6 Sq cms. Now the applied force on the base of the lantern. Force = Pressure x Area Force Imperial: = 29 x 44.2 = 1282lbf Force Metric: = 200 x 283.6 = 567kgf
Hello Pete. That's very interesting to see the formulas used for safety reasons of such a fount. While I do not understand it all I can see the final reason not to be unaware of problems that could arise. I found your remarks very interesting as I am sure many more members will. Thank you for a very good technical reply and the time posting it. Thank you so much.
