Repair of FL6 bulged fount bottom?

I just got this beast but the bottom plate of the fount bulges beyond the rim. The bulge looks quite symmetrical. The fount walls are steel and the bottom plate is brass. Is it feasible to resolder, remove and reshape the brass bottom plate?

 

@phaedrus42

That's a shame. It will be a big job to repair. It might be worth seeing whether someone has a spare tank, because these lights sometimes turn up in very poor condition and are used for spares.

I'll have a look at my tanks in the morning and see whether I can fathom how get the bottom on and off. With yours being distorted, it might require reinforcing some way.

I'll ponder, but someone more experienced in this particular task may be around.

Cheers

Tony

 

Hi Tony, is it really that big a problem?
Just wondering.
1) It doesn't sit on the base so the bulge doesn't affect stability.
2)If it doesn't leak now it probably never will since someone pumped it to who knows what pressure to achieve that.

Can you live with it? I think Zen and the art of M.cycle maintenance would tell me (perhaps only me) live with it.
How about you?

Rest of it is gorgeous.

<added - it takes a bit more fuel to fill which the pickup tube probably can't reach, but on the other hand, you have a larger space for water to collect from bad Paraffin and never be sent to the burner. I like it>

 

@JonD

The issue with the bulging bottom is the possibility (?probability) that the brass bottom has parted from the rest of the tank somewhere inside where it can't be seen, causing a weak point. That weak point may fracture on continued use at operating pressure.

I'm not trying to be a curmudgeon here: there is a lot of fuel in that tank.

One solution might be to use something like POR15 to seal the inside of the tank, and reinforce the bulged bottom externally with a steel bar. It's minus something outside so I haven't inspected my FL 6s yet.

Cheers

Tony

 

Hello Phil, in my opinion once a base plate has bulged then it's knackered, but some collectors have successfully fitted new base plates to old lamps.

 

Hmmm... I'll give the Tilley engineers a failing grade on this design then. Given the forces involved and the strength and characteristics of the materials they were working with, they should have realised that they left too little margin for safety. It should not have been too difficult or costly for Tilley to avoid the problem. After all, a host of competing contemporary manufacturers managed to get it right.

 

@phaedrus42

I have three FL6s: all have steel tanks and bottoms.

The rust in these steel tanks can be a real pain on the backside.

I don't know when they made the FL6s with a brass bottom, but in the X246 lantern series, bulging bottoms weren't a problem until models in the late 50s and, especially, the 246B.

I'm slowly working on an old petrol Lilor that had a rusted-out bottom. I've cut it out, and will, when I get the courage up, silbraze a new thick bottom on it (I'll have to protect the rest of the tank from heat while I'm doing that).

Your task is bigger than my Lilor, but, if the worst comes to worst, you could try something as dramatic as cutting the bottom off and fitting a new, heavier plate... but I would wait to see what better advice might turn up here over the next while.

Cheers

Tony

 

You can pressure test it by filling it with water and then pumping a little air into it. A similar technique is used to test Coleman tanks 5:30:



Oh wear goggles like the man.

 

at the risk of being thought crazy
why don't you stick some parrafin in it and see if it runs ok
maybe goes easy on pressure see if it leaks much or indeed at all
cannot see base moving much more every lamp you have don't have to be perfect
Pete

 

After that scary tale that Neil told about the FL6 that caught fire and then blew its bottom out I'm inclined to be cautious. At the very least I would try to re-flow the joint to make sure it is not fractured.

 

@phaedrus42 understand your caution - as Neil's tale was indeed most scary.
In the end I reckon that centred on neglecting to observe the device while in operation.

Light it & leave it... Would you do that?

I'm "Guilty as charged your honour" with candles and too much beer.
Pressure lamps , Aladdins and Petrol or Paraffin stoves only run under watch when fully/mostly compus-mentis (spelling dodgy? - meh)

I'm lucky. My wife is well versed in the operating parameters.. if she doesn't like the look of it it gets shut down... never mind I say it's OK.
<Over Ruled> Good Safety Officer.

 

I still would give it a go outside and watch it of course
there is risk on everything in life
if you need to repair the base put a steel plate over the brass brass pete

 

Well, fortunately it is a device which would not be used indoors very much It is in line for a full strip & repaint and I still need to order the seal kit and obtain the missing pump T-handle assembly, so it will be a while yet before it is ready for testing.

 

I recall discussing the failed base plate problem with Neil, (many years ago) and the problem was caused by a change in the soldering method from late 1956 onwards.

Neil may have more precise details.

 

Personally I like a nicely rounded bottom , uh hum

Some options there for you Phil, I'd have reservations over running it at a lower pressure though, in my mind the bottom hasn't held up to previous pressures when in a good state, now it's dished its in a lesser state.
Think I'd be looking at replacing the bottom (just my opinion), James has done this and shown how he done it in a thread posted here somewhere


Good luck

 

Removing and replacing a Tilley base plate

 

That was on a TL106 where you just have to melt the solder seam and it falls out. Much harder on this FL6 as the edge of the rim is rolled around the base plate so you would have to unroll it.

 

Mmmmm not the one I was thinking of, I'm sure you had to unroll the edges

Wasn't it a Blanchard

 

Personally I like a nicely rounded bottom
me too ray

pete

 

We got a few things in common Pete

 

Yes I did repair a lamp like that, it was a French lamp, a Succes, with a brass tank. I imagine it will be harder to unroll a steel edge.

 

Hi All,

Please excuse my ignorance, I am by no means a specialist, nor do I have the years of experience as the rest of the group, but reading the above has got me thinking.....if the bottom plate is rolled into the seam of the tank, will that not act as a safeguard againt it "popping out" under pressure? With this model being mounted on a stand, will it ever be set on the fount, where the rounded bottom will pose an issue?

As I said, not the expert here, but just my two cents.....

Jaco

 

Hi Jaco,

could happen this: Tilley FL6 explosion.

 

Hi Nicola, Thanks for that. Oh my , I never thought it can blow like that, just goes to show....
I will be very very vigilant with my lanterns and as Neil points out, maintenace is very important.

Jaco

 

It is a design problem. Most lamp bases are fitted as a cup shape with the vertical rim soldered to the tank rim and under pressure all the force pushes directly down and sideways which pushes the vertical base rim outwards which reinforces the joint. The base plate rim is actually inside the tank and subjected to pressure. In 1957 Tilley inverted the cup so the base plate rim is outside the tank and not subjected to pressure and this means that the force on the base plate tends to pull the vertical rim inwards which tears the solder seam. Bean counter design instead of an engineer. If the base is bulged then the seam is failing. I showed you what can happen so beware. Think on. That tank can hold a US gallon and if the base fails under pressure then you get a ball of atomised fuel/air mix maybe 12" from the mantle. There is a good chance it will ignite and trust me you don't want to be near if that happens. POR 15 will not cure the problem. That stuff works well on cracks and pin holes but it should never be used to provide a mechanical joint. With a flexing base plate the resin will just crack and render the liner useless. ::Neil::

 

So the question still remains:
Resolder the lead seal?
Remove, reshape and refit the base plate?
Replace the base plate with a new one?
Replace the whole tank?

I notice that the fount Neil reported on has a double step from wall to lip whereas mine above has a single step. The base plate of that one has its edge facing inwards/upwards inside the fount but on mine the base plate edge faces outwards/downwards outside the fount.

I wonder if it will be feasible to "spin" the base plate into a slightly flatter shape around its outer circumference in situ and then to resolder the seam?
On mine, the edge of the base plate is well and truly captured under the rim of the fount. It is hard to conceive of a situation where the whole base plate could blow out, barring the type of situation Neil described.

 

Mick had one like this a while back
he just tapped with a mallet a shallow depression so it sat flat on the base
and just ran it it was fine
pete

 

Pete, I think if I make a rounded wooden shape and tap it with a hammer along the circumference I can flatten the outside 3/4" of the bulge which should bring the centre of the bulge well below the level of the rim again. After that I will clean, flux and reflow the solder seam inside the fount. I must say the bottom seems to be quite heavy gauge brass sheet compared to that used on other founts.

 

yes that sounds a good idea
sometimes the old solder used on lamps is difficult to resolder
it is not like what we use nowadays and it just wont flow like you want it to.
good luck with your lamp I think its in good shape compared to some I have seen
pete

 

Hi Phil

Good luck and keep us posted

Not to sure how bashing the bottom plate to make the lamp sit better will increase the jointing surfaces that have already been ripped/torn apart, besides being difficult to clean that area well enough to make a good solder joint. Hope you get somewhere though, gotta keep these things running havnt we

Fingers crossed for ya