Bombarda Maggiora ad Acetilene da 320

Published on
December 29, 2021
Review Author(s)
Product / Stock #
Provided by: Vargas Scale Models


Necessity is the mother of invention. Once the combatants in the Great War settled into the trenches, the Italians faced a desperate shortage of heavy artillery. To help fill this need, Demetrio Maggiora invented a short range 320mm (12.6 inch) mortar powered by acetylene gas. The acetylene was generated in canisters like a miner’s lamp. The gas was transferred into a spherical combustion chamber where it was ignited to launch the projectile. The mortar was muzzle loading and had a very short range – just enough to reach the enemy trenches. It was first used in the Second Battle of the Isonzo in 1915 and was only in service for a short time until more capable weapons became available.


Vargas Scale Models from California USA specializes in interesting and unique subjects from World War One and the Interwar periods in 1:35th scale. All are CAD designed and 3D printed in resin. Sales are direct to the modeler on eBay.

The kit is packaged in a small sturdy corrugated cardboard flip top box. Inside are the instructions, and zip-lock bags with twenty 3D printed resin parts cushioned in bubble wrap. The instructions are two pages double sided printed in color. They consist of CAD renderings to highlight the assembly. There is no parts list or painting instructions. No decals or PE are included or needed.

The parts are printed in a gray resin. The kit includes the mortar, bipod, acetylene generators, vinyl hoses, six nicely printed mortar bombs, and an optional barrel extension. The nature of the subject calls out for a trench emplacement base.


Unlike cast resin, there are no pour plugs or mold parting seams to remove. Nor are there pin holes or air bubbles to fill. Unlike styrene, you get lots of detail with a shockingly low parts count. 3D printing does introduce a couple of new steps in the build process. The parts require thorough cleaning with a toothbrush in warm soapy water followed by rinsing in warm water and blow drying with your airbrush. To ensure that the resin is fully cured, lay out the parts in direct sunlight for several minutes. Too long in the sunlight will cause the resin to get very brittle. Some of the parts exhibit 3D print striations. Priming the unassembled parts with an inexpensive rattle can sandable, automotive primer or a good self-leveling hobby primer like Mr. Surfacer 1000 in a rattle can will fill most of these striations. The remaining striations can be sanded out.

Once the parts are cleaned up, the assembly is trivial. The instructions are minimal but adequate. Although the parts fit is excellent, dry fit everything before assembly. I used five-minute epoxy to give more working time to align the mortar tube, combustion chamber, and cone. Medium CA was used for the other joints.

Painting and Weathering

As the parts were primed with gray sandable automotive primer prior to assembly, I pre-shaded the assembled mortar with Tamiya XF-1 Flat Black and highlighted the upper surfaces with Tamiya XF-2 Flat White. From the few period photos, the mortar appears to a slightly lighter shade than the uniforms of the crew. This likely means that they were painted gray green. I used LifeColor UA 213 Grigio Verde Chiaro, thinned 1:1 with a mixture of LifeColor thinner and 10% Liquitex Flow-Aid. I gave the acetylene canisters a base coat of Tamiya XF-56 Metallic Grey followed by AK Interactive Worn Affects. One canister was airbrushed with Life Color UA 213, while the other was airbrushed with Tamiya XF-65 Field Gray. They were then moistened with water and chipped and scratched to give a very beat up look. The kit includes two lengths of clear vinyl tubing for the gas hoses. I could not get primer or paint to stick to these, so, I replaced the vinyl tubing with Evergreen rod bent to shape. The gas hoses were brush painted with Tamiya XF-57 Buff. With the base color and chipping complete, I applied a dot filer of various Winsor & Newton Winton oil colors and Mona Lisa mineral (white) spirits. After allowing the oils to dry, I airbrushed everything a glossy clear coat of Future. AK Streaking Grime was used as a pin wash followed by a light dry brushing with Winsor & Newton Yellow Ochre. I added a generic Archer data plate and sealed everything up with a matt finish of Testor’s Dullcote. Wear points were rubbed with a pencil and/or Uschi Chrome powder.


This kit highlights how CAD and 3D printing technology can give us good kits of unique and obscure subjects that are not economically feasible in styrene or even cast resin. The kit builds into an excellent replica out of the box. Due to the need for CA glue and epoxy, it is more appropriate for experienced modelers. I highly recommend the kit and hope to see more new Great War and Interwar kits from Vargas. Vargas Scale Models offers their kits for sale on eBay. Thanks to Vargas or providing the review kit.


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