Model 18th Century Naval Cannon for Metal Casting

I’ve been thinking about casting a functional model of an old-fashioned naval cannon, and I’ve made a model with which to make a sand mold. Most models I’ve seen posted look very accurate and are meant for dioramas, model ships, etc. But this model, being meant for casting, does not include a bore or a touch hole, since it makes more sense to drill those out after casting. Two versions of sprues were also designed, and files for them included. Both place the cannon upright with the muzzle end up, but sprue version A pours straight into the cavity at the muzzle, whereas sprue version B uses a wider offset pouring channel to fill the cavity from the bottom. It requires more metal but may improve cast quality due to decreased turbulence in the liquid on the way in.
It was designed to have a ½” (12mm) bore, but can obviously be scaled to any size…the limiting factor with such things is often the capacity of one’s metal melting equipment. With no scaling, this model has a volume of 11.9 in3/195 cm3 (Sprue version A) or 12.9 in3/211 cm3 (Sprue version B). Keep in mind that scaling the model by a factor of N will scale the volume needed by a factor of N cubed, so begin with your crucible’s volume and work backwards to the maximum size you can manage. The unscaled model is about 10” (254 mm) long, but since this is near the size limit for most bedslingers, I also divided both sprue designs into quarters as well as halves.

The photos are of Sprue Version A, unscaled, and Sprue Version B, Scaled to 125%.
A STEP file of the basic model is also included if one wishes to make more edits or divide the model differently. I guess one could also print the .STL of the whole cannon as one piece and melt it out of a plaster mold, too.

• Material: Doesn’t really matter, so probably use PLA of your least favorite color.
• Orientation: Flat side down.
• Supports: None.
• Layer height: 0.2mm.
• Walls, Top/Bottom layers: 2, 3/2 The only mechanical requirement of a casting blank is to withstand the stress of packing greensand around it.
• Wall thickness: 0.4 or 0.5mm.

• Infill: 15% Gyroid or lightning.
• Material required: A little over 50 g unless you scale the model.
• I have little experience with and less expertise in metal casting, for instructions on that you’ll need to consult other sources.