Body armor shell

[stryker20000]

I picked up a really nice new surplus French flak vest shell, this exact one: https://www.keepshooting.com/french-military-flak-vest.html and would like to in a sense puff it up more and make it slightly more ridged , especially around the shoulders if possible. I thought about using cardboard for it but I worry that if it gets wet the cardboard will get soggy and basically fall apart inside of the vest. Does any one by any chance have suggestions on what I could use besides cardboard that is ridged yet pliable?  I also thought of a cloth type material but not sure what would work best  

 

Thought I would also show off what I put together. Not the best era specific I believe but I feel it looks great. Tried going for a 2005 era Terre de Armee look

[hitmanNo2]

Camping roll mat is the go to item to add rigidity to armour carriers.

[stryker20000]

Hu, I never thought of that. I’ll look into that then. Thanks!

[RedRob]

I have used garden kneeling mats in the past. The same material as the fake plates, but much cheaper and can be cut to the correct size and shape.

[NonEx]

Similar to the above, but exerciser mat foam is also very good to work with. Rigid but flexible, and easy to cut and shape.

 

[Ivan le Fou]

Yoga mats with layers of cardboard are also good.

And perhaps cheaper.

[hitmanNo2]

Good shout on the garden kneeling mats.  Much better thickness and rigidity to work with compared to roll mats.

[Hardly1]

This packaging foam or this closed cell foam could work well. I think Plastazote is similar to what those floor mats are made of and you can buy it in sheet form.