Restoration project

You could solder the collar on the inside, having reshaped the body as best you can first.

If you find you must solder it on the outside and remove the verdigris, there are ways to ‘rapidly’ reform it - using acetic acid ( vinegar) should do it. ( O level chemistry, not faking antiques.)

I try getting the top section off, by grinding those rivets.

Since it's no longer gas-powered, it doesn't really need a working chimney, I wonder about re-shaping the tear then filling the top part with resin? I will be suitably high-up to not be very noticeable.

What a lovely piece of kit!

Copper is extremely ductile especially if constantly annealed. I think you could easily replace any part of that by forming copper round wooden shapes. Just gentle love taps will do it. I think if you have the time and inclination get some copper scraps from your nearest metal merchant,and a ball or straight peine hammer and start seeing what you can do

I restored an old brass lamp by polishing using a wheel kit on an electric drill and metal polishing compound

Got all the verdigris off OK

Less aggressive than steel wool

We didn't do any metal-bashing at school, but I fancy giving it a go one way or another, no need to think about any soldering until I can fashion something that looks the part ...

If you can fashion the right shape, you may be able to rivet it and so not need to clean up and solder the rest.

Lots of online videos

I am no panel beating craftsman. But I did a little work with copper in one of those 'art kits' to make a copper picture plaque as a teenager. Fun

If I remember correctly they did up something similar on the Repair Shop. Unless You particularly want to do the project, I would think up an appropriate sob story and see if they will do it for you.

I'll offer you this rabbit hole of information on restoring lamps:

So far I've used the dremel with carbide burrs to grind away the copper rivets holding the damaged section to the body of the lantern, I can get the gap to sort of close, will need some hammering against e.g. a piece of dowel as a former to get it closer.

The inside is very sooty as it was above the air vent, so will take quite a bit of cleaning to make it solderable, also most of my hammers seem to have gone into hiding, or have broken shafts.