Petromax pinholes - heartbroken

I finally got some parts and a seal kit from the UK and whilst waiting I gave this beauty a clean - no polish as it’s already down to the brass in parts.

It looks very solid and in great shape.

I fired her up and was overjoyed at the sound of my first 500cp Petromax.

When kero started to appear around the base I figured I’d not tightened something or needed to replace a seal which I thought was ok.

But my joy turned to heartbreak when I realised the leak was from pinholes in the base of the fount, which is surprising because it looks in fine condition.

Any repair is likely beyond my skills.

Note I have the original glass and the one pictured is for testing and burning.

 

Bugger .............
You may want to try some POR-15 or similar to coat the base from the inside with an epoxy resin sealant.
Good luck.
Cheers
Pete

 

Hi @Buckaroo
Sorry to hear that but take heart as there are some great success stories that folks have had with very similar lamp symptoms and as Pete has said there are ways to repair that don’t involve heating..
I hope that you manage to find a good outcome to where you are now,
Good luck with things

 

Right… I’ll do some homework and get on it! Thanks for the tip re POR-15

 

I have sealed the inside of several tanks after removing scales of rust. I used KBS fuel tank sealer (similar to Por15).
A trick I was told to stop it going off was don't open the lid. Use a nail to punch a hole on the can and using a syringe, only suck out the amount you need. then seal the hole with the end of an art style paint brush or similar. The sealer has stayed good for 2 years now.

The fuel pick up tube is also a concern regarding blockage. A recommended method is to connect a fishpond air pump to the tube and pump air into the tank until it cures. This also aids the curing process. Ops forgot, the valve and pickup are removable in a Petromax.

POR15

 

If all the pinholes are in the centre of the base (in the dish) you could probably solder using a fine point butane torch or similar. Localised heat - i.e in and out fast after a good clean and plenty of flux. Alternatively a mate who can solder a car radiator might be able to help.

 

Identify and mark the exact sources of the leaks. Are they really pinholes or are they cracks? If cracks, probably best to retire the fount. The number and location/pattern of leaks will determine whether soldering or a sealant will be the best way forward. Solder can be undone. Sealant cannot be undone.

It is a paraffin lamp, so small leaks are more likely to cause a mess rather than a fire. If you do use it with the leaks, do it outside and preferrably hanging rather than standing on a surface.

 

Yes it can or at least Caswells sell a product which they say will remove POR15. ::Neil::

 

That is good to know, Neil. Quite a performance to get it out again I suspect.

 

Sorry to hear about the pinholes. The good news is they can be repaired if its not too badly corroded on the inside. I'd usually solder them up.
Tank sealers might work too, provided its properly applied. You'd need to be successful on the first attempt because it'd be very troublesome to undo or remove any internal coatings once its cured.
The only thing I can imagine is a prolonged soak in methylene chloride paint strippers followed by many cycles of soak-rinses with strong solvent mixtures(acetone, MEK, toluene, xylenes, etc) before finally boiling in concentrated lye.

 

I was told on the stovie forum that exposure to lye makes brass brittle and prone to cracking. I suppose how long and how strong would matter.

 

Don’t give up… I sealed a Coleman L220 (slant) with POR15 and it’s still holding! I would think any good tank sealer should work.

 

@Buckaroo Some useful comments from members in my post on POR15 HERE. The Trainite lamp I used it on is featured HERE and the New Governor stove that was my main project for repair features HERE.

John

 

As always the advice is much appreciated - I’ll post an update on here when it’s fixed!!

 

I'd believe so because lye is such a strong alkali that it would remove some of the zinc out of brass(dezincification), leaving behind the copper. I'd not leave the metal in for too long. Just long enough to loosen the last bits of coating.

 

No need for all that, just use POR15 Cleaner Degreaser (Marine Clean) 946ml

It may sound expensive but it must be diluted, I've used it many times and consider it the best thing since sliced bread. Look in the tank, unless you can see seriously heavy varnish-like fuel residues then 1 part cleaner to 6 or even 7 parts hot (not boiling) water should work fine, full instructions are on the label. The cleaner goes milky when water is added and will come out milky if the the tank is clean, the heavier the fuel residue, the darker it will become. A bonus is it can be used again if it's not too contaminated.

 

Depending on the amount of pinholes I would go for soldering, it is a brass tank, maybe with an extra patch on top of the pinholes.
First check the inside of the tank if the pinholes are the first signs of a rotten bottom. In this case get another tank for safety reasons.

 

The POR-15 Marine Clean looks promising and convenient. I've checked the msds. I'd say the active part is alkaline potassium hydroxide with some wetting agents, surfactants. It'd certainly work with POR-15.
It might not work on Caswells epoxy-type coating though.

 

I hate to put too much heat on any lantern for fear of unsoldering something else. I’ve had good luck with POR, I’ll stick with it till something better comes along.

 

I've used epoxy resin thinned with methylated spirits. It's worked for me and is unaffected by the fuel.

 

Hopefully you will be able to repair it.

 

It is sorrowful when pinholes or stress cracks appear. I have a prized 1A Aladdin which after 30 years of ownership has suddenly developed stress cracks.

So know the pain.

One sunny day will get the big soldering iron out and finish soldering up the cracks.

Have read the comments on sealants with interest.

 

@Walkop I would go with the POR or a product similar to it. I would go with the soldering as a last resort. I’m over cautious when it comes to soldering, I guess…

 

I've seen a blowback when someone attempted to solder (with a naked flame) an old three legged paraffin stove with a leak - it's bloody scary! It didn't blow the tank apart thank goodness but the guy - who was very experienced - stopped and gave up immediately!

 

Which is why it is imperative that the tank / font / reservoir / fuel container - call it what you will - should be washed out with something which will remove ALL traces of fuel and varnsh-like fuel residue.

 

For soldering jobs on founts, I've not been using direct naked flames as the heat source from a torch for a while.
I've switched to using either a high-power electric soldering gun or just a pre-heated piece of thick copper. The latter is similar to the types used for jointing sheet metal, gutters, etc.
I find them far more controllable because the heat is more targetted:- without overheating the rest of the fount. Although not my preference, there had been numerous occassions that I even managed to effectively solder up pin holes without removing the fuel from the fount.
The only extra caution is: I'm using acidic flux solution(zinc chloride) for this. They are far more effective than resin flux. They remove oxidation even before the heat is applied. The entire fount(not just the soldered spot) should be thoroughly washed after the job is done to remove all traces of acid and chlorides. That's because the flux fizzles and gets somewhat spluttered all over the adjacent surfaces during soldering. Otherwise, they'll wreck future havocs on the fount, possibly creating even more pin holes.

 

Damn my Petromax has a tiny tiny leak somewhere from the base of the fount, it's so small I can leave it pressurised for 8 hours and nothing, but sitting unpressurised, after a week a get a few drops worth accumulating on the base of the tank.

 

You might need to check that the pressure releave screw on the filler cap remained open during non-operation. If its shut, variations in ambient temperature and conditions can make the fuel rise up to the jet tip and out. That might even be mistaken for a leak somewhere.

 

Thanks, I already thought this and made sure it was left open. A few days ago I've hung it up again to check with the presshre relief open and this time the lamp valve closed as previously it was open.
I'm hoping that this could be the issue, but suspect there is a tiny pin hole somewhere.

 

Brass doesn't tend to geht pinholes in my opinion. Instead, the tanks of Petromax (and other makes) tend to get stress cracks under certain conditions. If this would be the case you should abandon the tank, because its use would be unsafe.