So I had a couple of these cheap broken aluminium waterpasses for a long time and eventually I decided to make something usefull out of them: a tool cases (well... it may be a "something else cases" as well). And it is a pretty simple project.
Prepare the raw materials and the work-fuel (tea at this time).
Cut pieces into lenght. I was making a cases for a hacksaw blades wich resulted into specific dimentions.
File the edges to make them smooth and nice... and filed.
Cut a back (unremovable) plug from any piece of wood ypu like... or hate (it depends of your woodworking skills).
Hammer the plug into place.
To secure the plug I just made indentations through the aluminium into wood. I used soft pine so it worked well enough but any glue or screws will do the job even better.
Use tools to make the removable front plug. It fits snuggly inside the case. Notice a little step: it prevents the plug from falling all the way into the case; and a notch at the top makes it easier to pull.
Finish wooden parts with enything you like and...
... have a usefull thing for your workshop.
Thank you for your attention.