Thanks for the props, Ryan!
Something that I would offer up with regards to the design of US firebase bunkers in Vietnam is that they are all configured to fit the available space as constrained by the micro-geography of the terrain. My observations (as I researched FSB RIPCORD) was that on any given firebase the artillery firing positions were often very similar in layout and construction. However, those same types of artillery pieces might be located in very differently laid out and constructed positions on other firebases. Available materials and the specific combat engineers that did the “rough” work also had significant influence on how positions on different firebases ended up configured.
With specific regard to RIPCORD, the 155 mm howitzer positions were initially excavated and graded by 101st Airborne Div. (3rd Brigade) combat engineers, but actually constructed and occupied by a howitzer unit of the RVN 1st Infantry Div. The RVN arty battery moved to a different fire support base, and their gun and crew positions were occupied by the American 155 mm battery. The troops, both RVN and US, continuously worked on and improved their gun, crew, and ammunition bunkers continuously (as well as repaired damage from incoming PAVN mortars and rockets). These changes can be observed in photos taken over the entire period of occupation of FSB RIPCORD.
I used two-part epoxy for the various sandbagged positions on our RIPCORD dio. I actually made some gauges, one to scribe the thickness, one to scribe the length and a third to scribe the width, of the sandbags. Rather than make them individually, I made most of the sand bagged walls and roofs as single layers of epoxy putty, then used the gauges to lightly scribe the general outlines of the bags, followed by sculpting their shapes with homemade tools (mostly round toothpicks with shaped ends). Aves Safety Solvent was used for clean up and as a release agent on the tools.
Most of our bunkers were made a multi-part masters and then copies were cast using RTV molds and urethane resin. This was done for almost all of the various bunkers: 105, 155, 82mm mortar, individual fighting positions, command bunkers, crew bunkers, ammo storage, etc. Only a few of the visible bunkers were built as stand-alone, unique models. This was possible, because the terrain, available materials, and units doing the construction imparted a large degree of uniformity in the layout and construction of the various different types of bunkers. So, all of any particular type tended to be generally very similar in layout and materials.
We also ran into major problems with finding commercial kits of US equipment in 1/72 scale. We used as many as we could find, but in the end, we also mastered (either by hand or 3D printing) many of the details which, like the bunkers, were cast in resin. This also included the several thousand tree stumps that surround the firebase.
I suggest that you contact:
HQ72 Resin and ask them if they have any of the small details still available from the FSB RIPCORD diorama project. They did a large amount of the resin casting for us.
If you want, you can DM me here, and I will try to put you in touch with another resin caster who made many of the castings of small details for us. He no longer runs a formal casting business, but he may have some things useful for your project.
Finally, we commissioned a 3D designer and printer in Spain to sculpt and then print over 200 be-spoke 1/72 artillery crew and infantry figures for our RIPCORD diorama. His Facebook handle is:
Holden8702 and you can contact him on Facebook.
He does a lot of custom figure 3D designs and print commissions in all scales. He might even have some of the FSB RIPCORD artillery crew and infantry figures still available in his catalog.
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