MK V Dive Helmet – basic shape

So this is the starting point for the helmet. A plastic inflatable ball with a cardboard base:

The starting point for my helmet. A little crude, but I think it will work

Now to coat it. I’m going to use plaster-coated cloth strips that I got from the hobby store.

I took the roll of plaster cloth and cut it into strips about 2-3 inches (50-75mm) wide. The gauze/cloth strips are just dipped into warm water. The excess water is squeegeed off with your fingers, and the strip is draped over the ball and cardboard

I made a real mistake by using a few cardboard strips for the “ribs.” This left a sunken area in between the ribs, and I stuck in a few cardboard strips to try and fill it in. I think it would be much better to use more ribs or, better yet, generate a conic section that fits the shape when rolled up, and cut it out of cardboard or similar material.

Mk V Diving Helmet

So I decided to build a facsimile of a U.S. Navy diving helmet, the Mark V. Something like this one (which was auctioned off at Vallejo Gallery):

Dive helmets like the Mk V are widely-recognizable, and appear in pop/pulp fiction, adventure stories, and graphic novels/comics; anywhere there’s a style-heavy industrial motif, like steampunk. The strange rounded rectangles on the front viewport, and the globe-shaped hat are instantly familiar, and serve to set the tone for an other-worldly scene, or vintage setting. Like in this H.P. Lovecraft themed poster by Italian artist Francesco Francavilla

The dive helmet commonly known as the US Navy Mk V, as shown in various pics found around the internet.
Here’s a cool video that shows how the helmets are manufactured.