One of the exhaust hangars on my tintop has rusted through, yet the exhaust pipe isn't in such bad condition, so I'm going to make a new hangar and weld it on. Are there any problems with welding to aluminised steel? Does it give off fumes like welding through galv?

You should have no real problem Mig welding on an alu coated exhaust.

Will help if you can remove some of the coating with a flap disk or file.

Certainly not the same nasty toxic fumes as galvanised metal.

That said, best wear a dust mask if grinding, aluminium is none too good for you if ingested

If gas or tig welding, you'll need to remove the alu coating because it will stop the weld pool from flowing.

Thanks. I'll grind the rusty part of the stub of the old hangar so I'll make sure the area to be welded is clean.

shouldnt be a problem. ive done it before with success.

Only problem is it tends to spit a lot. The trouble with aluminised boxes is they look fine on the outside but are rusting from inside; Dont be suprised if it's paper thin and you blow holes in it.