Having created this new restoration section on the forum, I decided to transfer this post from where it was originally.
In order to fix collapsed leather shells you have to rehydrate the leather ie put moisture back into the leather to soften it. Once this is done, one has to block the shell top back into its original place then let it dry. There are 2 ways to hydrate. First method: Frequently, we find shell tops which have sunk out of position due to the weight of the spike fitting. Wet a cloth with water, turn your haube upside down and pull the liner up out of the shell so you do not get it wet. Place the wet cloth into the top of the shell and allow it to sit for an hour. It may take more than an hour to soften up the leather on some helmets. Check frequently as you do not want to add too much moisture. Too "wet" can lead to finish flaking off. The leather is ready when you can push it back into place easily with your fingers. The Second method of hydration is more suited to putting moisture into an entire helmet. For example an OR's helme that has sides collapsed so that it looks like a deflated football. Place a plastic grocery bag into the shell to protect the liner and fold the sides of the bag out over the sides of the shell. Put a ball of wet newspaper into the bag. Place helmet into a larger plastic bag and seal it up so moisture can not escape. The water in the news paper evapourates into the air within the larger bag. The helmet is then hydrated and soft enough to block back into proper original shape. After one day of hydration check the helme for softness. You MUST keep checking daily because if the shell gets too wet the finish will flake off. You can also ruin the liner. This method demands CARE and CAUTION! I KNOW CAUSE I SCREWED UP THE FINISH ON AN OFFICER SHELL RECENTLY AND GOT INTO A WORLD OF HURT!!
BLOCKING: Place a plastic grocery bag over a styrofoam head form. This is done so the styrofoam will not stick to the liner. Pull the helme down until the collapsed top is pushed back into position. I use quilters "T" shaped pins to pin an officer shell to the head. Scales are off so I can access the 2 side holes in the officer shell. For an OR helme you can tie elastic around the M91 side posts placing it around the base of the head form. This exerts enough pressure to keep the top in position. Allow to dry for 2 days at least and it will be blocked into proper shape.
You can use this head form method to block a helme whose sides have collapsed as well.
Most leather helme parts can be put back into shape by hydrating and then blocking. For example, repro OR's chin straps. We all know how crappy they look where the strap bulges out around the M91 post fittings. Solution: Wet the strap with water pull it tight around the back of the skull on your plastic covered head form. Pin it to the form using the holes in the end fittings. Allow to dry for a couple of days. The strap will now be tight to the end fittings and have a nice curved shape that fits well against the shell of your helmet.
_________________
In order to fix collapsed leather shells you have to rehydrate the leather ie put moisture back into the leather to soften it. Once this is done, one has to block the shell top back into its original place then let it dry. There are 2 ways to hydrate. First method: Frequently, we find shell tops which have sunk out of position due to the weight of the spike fitting. Wet a cloth with water, turn your haube upside down and pull the liner up out of the shell so you do not get it wet. Place the wet cloth into the top of the shell and allow it to sit for an hour. It may take more than an hour to soften up the leather on some helmets. Check frequently as you do not want to add too much moisture. Too "wet" can lead to finish flaking off. The leather is ready when you can push it back into place easily with your fingers. The Second method of hydration is more suited to putting moisture into an entire helmet. For example an OR's helme that has sides collapsed so that it looks like a deflated football. Place a plastic grocery bag into the shell to protect the liner and fold the sides of the bag out over the sides of the shell. Put a ball of wet newspaper into the bag. Place helmet into a larger plastic bag and seal it up so moisture can not escape. The water in the news paper evapourates into the air within the larger bag. The helmet is then hydrated and soft enough to block back into proper original shape. After one day of hydration check the helme for softness. You MUST keep checking daily because if the shell gets too wet the finish will flake off. You can also ruin the liner. This method demands CARE and CAUTION! I KNOW CAUSE I SCREWED UP THE FINISH ON AN OFFICER SHELL RECENTLY AND GOT INTO A WORLD OF HURT!!
BLOCKING: Place a plastic grocery bag over a styrofoam head form. This is done so the styrofoam will not stick to the liner. Pull the helme down until the collapsed top is pushed back into position. I use quilters "T" shaped pins to pin an officer shell to the head. Scales are off so I can access the 2 side holes in the officer shell. For an OR helme you can tie elastic around the M91 side posts placing it around the base of the head form. This exerts enough pressure to keep the top in position. Allow to dry for 2 days at least and it will be blocked into proper shape.
You can use this head form method to block a helme whose sides have collapsed as well.
Most leather helme parts can be put back into shape by hydrating and then blocking. For example, repro OR's chin straps. We all know how crappy they look where the strap bulges out around the M91 post fittings. Solution: Wet the strap with water pull it tight around the back of the skull on your plastic covered head form. Pin it to the form using the holes in the end fittings. Allow to dry for a couple of days. The strap will now be tight to the end fittings and have a nice curved shape that fits well against the shell of your helmet.
_________________