Author Topic: One way to fix large holes in a lantern fuel tank  (Read 184 times)

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One way to fix large holes in a lantern fuel tank
« on: September 29, 2017, 03:44:22 PM »
My current project was a very rusty Little Wizard.

     ( Note: some sort of breathing mask or filter is highly recommended in this repair )

After a week of so in the molasses bath and several Brillo rub downs, discovered more that a few holes, some large, in the tank bottom.

First set of 3 images shows the holes, some of which were too large to support the POR-15. I pressed the metal around the holes to make sure the metal in total was not weak before proceeding. The metal did not flex so went forward with patching.

Used a Dremel 150 grit scour wheel to clean the metal and then used my 140 watt soldering gun to fill the holes working from the outside edges of the bigger holes inward, letting applied solder cool before putting on the next ring. Eventually, the holes sealed shut.

Ground and sanded the solder down to the surface to make sure the solder covering the holes was thick enough to support the POR.

I covered the pin holes with painters tape to hold the POR in the tank. After 3 days, the POR had nicely sealed all holes in the lantern.

Looking at the bottom, there were a lot of pits that were not holes but were a weak spot and a collection point for outside dirt. Did a search for liquid metal fillers and discovered Permatex makes an automotive liquid metal that was grey in color. Got a 3.5 ounce tube from my local farm supply store (they had a wide range of Permatex items from gasket compounds to the epoxy putty you kneed together before applying to metal fillers) for $2.50. It's also on Amazon for $5.57 and I'm sure in other stores as well.

The product is very similar to wood filler and it dries or sets quite fast when applying (clean up is also with acetone). I found the best way to use it is with a finger cot and to put a small dab on the finger tip and apply it quickly with pressure to the small pit holes. Then smooth over the excess and moved on to the next hole.

I let it dry for a day and then used Dremel scour pad to remove the excess (the stuff is hard to "sand" down but it does leave a smooth, filled hole).

Finished the entire bottom buy using 320 grit on a rotary drill pad followed by steel wool for a semi-gloss, smooth surface. One coat of diluted linseed oil and it was done. Came out better than I expected. No holes, pits filled and serviceable. The soldered holes are harder to spot than the metal filled pits.

A second coat of POR-15 was applies to make sure the tank was sealed.

That filler is great. Best $2.50 I've spent in a long time. Takes a bit of trial and error to lean its use so clean up/off is easy and does a nice job filling small holes.
            John . . .

              

Offline Dan/Panther

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Re: One way to fix large holes in a lantern fuel tank
« Reply #1 on: September 30, 2017, 12:20:10 PM »
Is the solder recommended for use with fuels ?

D/P

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Re: One way to fix large holes in a lantern fuel tank
« Reply #2 on: September 30, 2017, 02:02:58 PM »
Is the solder recommended for use with fuels ?

Good question, don't know for sure. The lantern site says not to solder small holes but to use POR-15 after the holes are taped over. Some of the information on the POR site deals with restoring motorcycle tanks, metal work first and then adding the tank sealer. I would think regardless of how a hole is "fixed," the POR-15 would safely protect the patch from the fuel, forever.

POR-15 Tank Sealer Description:  "POR-15 Fuel Tank Sealer was formulated and developed in our own laboratories due to the demand for a high-tech sealer impervious to all fuels, including the new Stage II fuels which have a high alcohol content. POR-15 Fuel Tank Sealer has superior strength and fuel resistance, and does not contain Methyl Ethyl Ketone, a highly flammable and deadly carcinogen (cancer-causing). POR-15 Fuel Tank Sealer is non-flammable and is environmentally safe."

That tape method works great for pin holes and cracks but using it as the main filler for a hole large enough to put a pencil eraser through to me would leave a large area of soft synthetic material on the bottom and subject to puncture if the lantern should be placed on a sharp point. Didn't want that risk.

This is what they say on the lantern site about soldering tanks:  "If cleaning the lantern exposes weak spots in the tank, creating pinholes, use the tank sealing method below (POR-15 method).  Soldering pinholes is not the best solution, as more holes are bound to develop."

They do not address large holes. Since the holes I had were "drilled through" and not the first part of a large area to be corroded away (I would have stopped working on this lantern if the bottom were soft), I used the solder to recreate a hard metal patch knowing that I would be putting 2 coats of POR-15 into the tanks to seal the pin holes and cover the solder from the inside. The POR-15 is a tough liner resistant to any and all types of fuels. Once cured, it produces a like new fuel tank from the inside.

Any lantern tank that I have ever had that shows any weakness has always been coated with POR-15, even if there were no leaks spotted on cleaning. I use acetone to get the water out of tanks on their final rinse and if there is any crack or hole, not matter how small, the acetone will leak through - a good method to test tanks. I prefer to over engineer the restoration, to error on the safe side since these do deal with fuel and fire.



            John . . .

              

Offline 19and41

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Re: One way to fix large holes in a lantern fuel tank
« Reply #3 on: October 11, 2017, 02:57:54 PM »
I would bet the only soldering product that would affect the fuel would be the fluxing agent, which should be cleaned from the repair after the work is done. 
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Offline andy1702

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Re: One way to fix large holes in a lantern fuel tank
« Reply #4 on: October 13, 2017, 07:18:12 AM »
I've soldered up various fuel tanks on stationary engines without any problems. I just used a reel of plumber's solder and flux paste. I didn't even use POR15 in the tank afterwards. My logic was if I'd fixed all the holes with solder what do i need the POR15 for? These engines vibrate a lot when running and the tank is still fuel-tight after two or three years, which is more than can be saif for tanks fixed with the various commercially available putty / pastes out there.
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Re: One way to fix large holes in a lantern fuel tank
« Reply #5 on: October 13, 2017, 08:05:55 AM »
I've soldered up various fuel tanks on stationary engines without any problems. I just used a reel of plumber's solder and flux paste. I didn't even use POR15 in the tank afterwards. My logic was if I'd fixed all the holes with solder what do i need the POR15 for? These engines vibrate a lot when running and the tank is still fuel-tight after two or three years, which is more than can be saif for tanks fixed with the various commercially available putty / pastes out there.

That is true and a good soldering patch is a permanent fix. Actually, a large bead of solder on a crack of an engine tank is probably better that POR-15 in that the solder provides both a plug and structural support to the crack.

The problem with lantern fuel tanks is pin holes, multiple holes so small solder won't go into them and of course, the excess on the surface is ground down to flat to match the surrounding surface so if the pin hole is not filled, grinding it flat will just open the hole. And I'm talking about pin holes so small that light doesn't even make it through especially if near the bottom bead or crimp. Acetone does leak through so it's a good test. On this lantern, I unfortunately did not tape all of the pin holes shut and ended up with POR-15 leaking out of about a half dozen holes which was quite a mess. Those holes were in places that could not have been taped - should have just taped the whole tank but hind sight is always great, isn't it. And since I knew there were larger holes in the tank, I did not do the acetone test which would have showed all the pin holes, my error.

The POR that ended up on my bench cloths and other things turned hard as a rock so I assume the cured product would be as strong and as tough as the metal tank itself. How long will it last? Don't know. Longer than me I suspect.

I use POR on any tank that shows stress marks as well, quite common on brass tanks. It's a great liner, a tank within a tank, and since these lamps are set on tables inside homes, I just don't want to take the chance of fuel on the finished wood surfaces.

This was the first lantern tank I ever had to solder due to the large size of the holes. The soldered holes were fine when ground down flat with the surrounding surface, it was the dozen or more pin holes elsewhere that caused me to go to the POR-15. These lanterns have been sitting for 50 to 75 years with moisture collecting inside the tanks. In hind sight, to be safe I should have put one coat of POR-15 tank sealer in every lantern I restored. Too late now. But the ones that needed it turned out very well.

If I remember correctly, back in the 50s people used to braze cracked gas tanks, but only after the tanks were filled with water for obvious reasons. I guess that was even a better fix than solder.
            John . . .

              

Offline 19and41

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Re: One way to fix large holes in a lantern fuel tank
« Reply #6 on: October 13, 2017, 01:22:49 PM »
A good thing about a thread like this one is to see and understand all the means of repair so the right one, or more, can be used as the situation merits.  I once was leery of my sheet metal soldering skills until getting the 200 watt class Weller soldering gun.  That thing is an irresistible force.
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Offline andy1702

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Re: One way to fix large holes in a lantern fuel tank
« Reply #7 on: October 21, 2017, 01:10:17 PM »
The big problem with soldering tanks is getting a soldering iron powerful enough to put enough heat into the metal. I tried and failed until I tried a gas torch, which worked quite well.

Por15 is pretty good for sealing suspect tanks as Teleplay said. The only problem I've ever seen with it is that under certain circumstances it can flake off the inside of the tank (probably because it wasn't applied right in the first place). This wouldn't be a problem for most oil lamps, but for pressure lanterns or engine tanks it's VERY bad because the flakes get sucked into the fuel line. This is the reason I don't use it unless I absolutely have to.
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Offline twocvbloke

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Re: One way to fix large holes in a lantern fuel tank
« Reply #8 on: October 21, 2017, 02:57:05 PM »
Don't know what the quality of them is like, but there are these large irons available for not a lot:

http://www.ebay.co.uk/itm/162530655164

:)

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Re: One way to fix large holes in a lantern fuel tank
« Reply #9 on: October 21, 2017, 03:03:26 PM »
I agree with that.

My 20-40 watt soldering irons for small electrical work didn't work for this so I used a 1400 watt Weller gun and filled the hole, the big one, by melting a ring around the hole leaving a smaller hole. Let it cool and filled in a bit more with another ring being careful to get the new solder to attach well but not melt the prior solder off of the tin. Did that until the hole was completely filled. Again, was just trying to provide a metal patch, a support, to hold the POR-15.

The approved way the tin lantern people say to use POR-15 is to first clean out the tank with a foot of sash chain and vinegar. Swirl the chain around inside the tank in about 3 ounces of vinegar. Dump it out and repeat until clean vinegar pours out. I then dry the inside with acetone, 2-3 rinses of 2-3 ounces of acetone, dry with hair dryer on high heat and a shop vacuum (sucks out the water and acetone as they are heated off the surface). Then two coats of POR-15.

Soldering a lantern is problematic in that a soldering iron is not hot enough to keep the lantern from playing a heat sink and a torch is so hot that it can melt other solder joints and you end up with a lantern in pieces. I've used the 1400 watt gun to reattach wired, tubes, fuel spouts, burner cups and in that one extreme repair, reline the mixing chamber with a flat brass piece bent into a circle.

As for pressurized tanks, yes, that is a problem. I am currently restoring a Coleman 220K lantern I bought in 1980 but haven't used for a good 20 years. In the process of cleaning out the inside of the fuel tank. Discovered everything inside the tank was coated with a layer of red "sealant" ranging from 0.0025 to 0.0004" in thickness. Coleman started using tank sealant in tanks after the 70s. Coleman experimented with coatings, some red and some whitish pink. They didn't do long term studies and my coating was coming off in the fuel causing the tiny hole at the bottom of the fuel/air tube to get blocked. My lantern would burn poorly for a few minutes and then die out. Anyway, the flaking coating caused problems and is no longer in the tank. Coleman collectors said the tanks were not coated before the 70s and they did not rust out as long as water was kept out of the tank. So, I'm staying away from recoating mainly to keep from painting the check valve shut or having the new coating flake off and create the same problem, a blocked fuel/air tube. Something easily fixed in a kerosene lantern, replace the wick it it no longer wicks up fuel to the burner.

Bare metal inside a fuel tank is always preferable to any coating, unless really needed.
            John . . .

              

Offline 19and41

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Re: One way to fix large holes in a lantern fuel tank
« Reply #10 on: October 21, 2017, 06:37:43 PM »
Don't know what the quality of them is like, but there are these large irons available for not a lot:

http://www.ebay.co.uk/itm/162530655164

:)


Those look like they have the power, but I would recommend using a straight chisel or screwdriver tip extending no more than 1- 1/2 inch from the heater.  That will deliver the maximum heat output to the work.
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke