I purchased a set of dug-up battlefield helmets not so long ago.
They were really rusted so I decided to clean the one that was in a worse condition in some oxalic acid.
There wasn't much paint left and the top of the helmet had few rusted through holes and a bit of the back was chipped off/ missing.
After, the only thing I found inside the helmet were the numbers 293.
So I decided to restore it only because it wasn't in really good condition to start with (Air vents nearly gone, etc).
I used an anti-rust paint to coat the helmet and to stop further corrosion and oxidization of the metal.
Then I patched the rusted through parts of the helmet with fibreglass and put on another coat of paint.
When it was dry, it was time for the filler.
I started off with a rough coat of filler to patch any major holes and pits on the surface of the helmet and then i sanded it down using an oscillating multi tool as it allowed for a flat sanding pattern.
After that followed a smoothing coat which would patch any smaller pits in the filler and would create a smooth helmet surface.
It took about 4 tries with the smoothing filler until a satisfactory look was achieved.
Because the air vents had almost rusted away completely, I made some replacement ones out of resin.
I first made a wax model similar to one of the air vents and created a mould of it.
Then I used resin to cast a new air vent and after some minor sanding and buffing, I stuck it on to the helmet.
Eventually I painted the helmet with a silver paint and then followed with a coat of woodland grey which is probably the closest colour I could get without having a specially made paint.
I also textured the helmet using sand (I know they originally used aluminium oxide but I didn't have any).
Please let me know what you think and how i could try to maybe age it, etc.
I still have to work on the inside of the helmet.