Petromax HK250 restoration

The black spots are: rust, "blank" metal.
You will not get the shiny new look back with any treatment, I am afraid ;-)

There is also no easy, speedy, wonder stuff that gets an old lantern clean again. It's all to elbow spit and lame hands from polishing.
For electro plating the metal must be clean, spotless and it will not remove dents and/or pitting.

 

If they are rust as you say, why a rust remover or even better a rust converter (like tannic acid) will not stop the corrosion? My issue is not to make it shiny again. I understand that this is not possible anymore. My target is to stop or slow down corrosion. For example, tannic acid turns rusty metals to black. I have no problem with this. Let it be black. Will corrosion stop? Or prevented?

 

I have no experience with chemicals. But others may.

 

Fighting rust on heated parts is not easy. You can make that part clean and shiny by keeping long enough in strong citric acid solution and scaping with steel brush - it can be done. After that you have to use some heat proof rust prevention, because most of the plating will be gone. It can be painted with some heat resistant paint. I personally heat and quench such parts in oil to cover with (reportedly ) heat&rust resistant layers. I just prefer that dark, oldish look then new paint in old lamp - up to personal preferences. I am more into "repair" then "restore"
all the best,
Piotrek

 

Dear Antonis,

yes the tannic acid or other rust converter will stop that rust, but not for long. It will need protection just as a new piece of mild steel will too?

good advice from other members and hope you can hunt down a solution

p.s. there may be alternatives to using a battery charger? have a look online as some folks use plug in phone chargers as the power source or similar?
lots of help online with nickel plating too

 

Thanks @podbros but I do not think that plating will work, as the metal is not completely clean. Unless it is possible to fully clean it with what @Piotrek wrote, that is to keep it in strong citric acid solution, maybe for days, and then scrap with steel brush. If this is possible then maybe it is the best method for me. I was just reluctant to use string citric acid solution for long times fearing I will create more problems. As I wrote before I do not mind about the dark color. I only care to prevent rust.

Dear @Piotrek can you provide more details for your oil method? Thank you.

 

@Antonis Tsolomitis - after rust removal and covering steel parts in WD-40 I heat them with gas torch. Repeated several times. Or after first layer of WD40 I drop these very hot parts into some oil - usually pot with boiled linseed oil. Then take it out, remove excess of oil with paper tower/rag and heat and quench again, and again After that I just cover them with the last layer of boiled linseed oil and that layer will burn out or just harden when lamp is working.
An example of treated parts are below - that dark cantering plate, small steel parts and even the inner casing. Covered with dark blue/black layer. Their surface is not smooth because they were very, very rusted. It theory the best method would be to nickel plate such parts again, but I have not reached that level yet
From the other hand I managed to spill 1L of boiled linseed oil in the kitchen recently, so better do it when females are out

Sometimes I am really not sure what to do with that old rusted parts, because the worst scenario is to clean them and just leave unprotected - rust appears immediately on such clean unprotected parts. Once, after cleaning I just covered that cantering plate with thick layer of graphite grease - it should block any moisture and air for a long time and create some protective cover, but this is not a method I would recommend for wider usage. An experiment... I will check this out ten years later
Steel parts that are not heated during lamp operation - I clean them and remove most of the rust (citric acid soup, steel brush, ultrasonic cleaner, whatever feasible) and then cover with APP RSTOP anti corrosion agent. After it dries out I cover it additionally with boiled linseed oil just to add another layer. Boiled linseed oil smells and dries out for very long time (days/weeks) but finally created some thin transparent layer. I like the smell (my wife hates it ), I like that this is some old and cheap traditional method so I use it. It is up to you at the end and you can even paint your a lamp in pink colour and be happy
all the best,
Piotrek

 

This is very nice. I was impressed that this works for the inner casing. I always did not know what to do with this. Modern lanterns have it plated. But in old lanterns it is bare metal. This is very nice idea. Thanks. I will look for linseed oil.

 

Other solutions - high heat stove black paint presented below
Petromax 827 (1937)
I tried once, but paint peeled off. Maybe because that was small a 100cp lamp and while pre-heating flames were directly reaching inner casing.