This is a good one .I was rackin' my brains out tryna figger out how to make the corrugated metal used in the First World War .Knowing how metal is formed, and owning a pittsburg joint machine , I was a little ahead of the game .Lookinig in my stash one day for 1/24 figs I came upon 
this kit Tamiya Pit Crew #20011:
Included in the kit is a guard rail:
Mounted to a boardand re-enforced with .125 flat bar evergreen plastic,see where we are goin' yet?
Went to the dollar store and got 5 pizza cutters:
Dismembered the cutters ,drilled out one handle and all the blades ,used 1/4" fender washers for spacers and the handle in the middle, 3" long 1/4 20 bolt w/2 nuts on the outside to lock it all together:
All spaced to fit in the guard rail groves:
Using K&S .005 brass sheet ,cut with scissors ,roll back/forth with increasing pressure to produce a more than acceptable WW 1 corrugated trench sheet. 
Green is masking tape to protect.
With different 'guard rail' spacing and reducing the fender washer spacers different scale corrugated sheet can be fabricated . Total ca$h out lay : $5 for the cutters , $10 for the kit (ebay) , $3 for the brass ,less than$20 ! I was not aware of the guard rail until looking in the kit and staring at it and seeing it was perfect but not believing my eyes!! Got a little excited when it was coming together and this happened:
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