Early in WW1, once the war of movement turned into trench warfare, the Italians desperately needed heavy artillery. Desperate times call for desperate measures, and lots of innovation. Demetrio Maggiora responded to the need and invented a short range 320mm (12.6 inch) mortar powered by acetylene gas. The acetylene was generated much like that for a miners lamp. The gas was transferred into a spherical combustion chamber where it was ignited launching the projectile. The mortar was muzzle loading and had a very short range, just enough to hit the enemy trench line. It was first used in the Second Battle of the Isonzo in 1915. It was only in service for a short time until more capable, and less cumbersome weapons became available.
Vargas Scale Models released another very obscure and interesting subject. Like their other products, it is 1:35 scale 3D printed resin. The kit includes mortar bombs and an optional barrel extension. I chose to depict it without the barrel extension. The kit included vinyl tubing for the acetylene hoses. The paint would not stick to these so, I replaced them with styrene rod bent to shape.
Like all 3D printed resin kits, it requires a thorough scrubbing in warm soapy water and a few minutes in the sun to ensure that it is completely cured. I primed it with cheap, rattle can automotive sandable primer. This does a fine job of filling the 3D printing striations. After pre-shading, I finished it with Lifecolor UA 213 Grigio Verde Chiaro. I chipped the canisters using the hairspray technique. The model was weathered with Winsor & Newton oil paints and AK weathering products. The color of the mortar ammunition is my best guess based upon a couple of period mortar bomb photos and period drawings of artillery ammunition.
This was a quick and fun little project. And very unique. I love these strange WW1 and interwar subjects with people trying new ideas. The 3D printing technology allows us to get interesting kits like this that are too obscure for the big companies to do in styrene.