Block printing I: Masonite-cut

Spending some time at my parents house. No woodwork yet this summer but I've wiped the dust off my old proof press and set it up in the garage. I've used it mostly for small lino cuts earlier but now I wanted to do something larger. I also wanted to use non conventional tools for creating the shapes for the block. Tools like band saw, regular drills and  the "chisel-drill".  A fantastic device that makes square holes. No I'm not kidding, see picture below! I picked masonite board as my material for the block. It worked fine with the flying flaming ape-scull where I used mostly the band saw (I have to find out a way to make the colors align better though). But  not so well with the big ship where i had to  use normal woodcutting tools for some of the details. The masonite is  quite hard on the surface but soft and cardboard like underneath, which makes it fragile. And the water soluble color I'm using makes the masonite swell. Maybe I can find something to harden it with once it's cut? Otherwise I don't think it will last for many prints. Some varnish maybe? Or oil?

The test prints are approx. 30 x 60 cm.