3D Durability: Thermal Defense Solutions’ Suppressors

By Oleg Volk

Some would describe sound suppressors as “reverse heat engines” acting to slow gas expansion and cool the gases by disturbing flow and absorbing heat. Unlike muzzle brakes that redirect recoil forces, suppressors dampen recoil by containing expanding gases. A good sound suppressor cuts peak recoil by 25% to 40% by slowing the gas enough to make a perceptible difference in shooting comfort. The problem with conversion of these forces is that it eventually can accumulate to the point of failure of structural integrity of the suppressor itself. Suppressor makers using titanium and stainless steel found that even those materials can come short of required performance for high-volume shooting. Inconel 718, an alloy of nickel with a little chromium, iron and traces of a dozen other metals, appears to be the perfect suppressor material. Resistant to heat, erosion and corrosion, with less thermal expansion than stainless steel, it would have been perfect but for the cost of machining it. Since Inconel dulls cutters rapidly, it is often used with water jets and welding, but most manufacturers reserve its use for blast baffles only. Thermal Defense Solutions (TDS) makes the entire suppressor from Inconel!

The advantages of making the entire suppressor from a single material are clear: even thermal expansion, excellent resistance to erosion and solvents throughout. Compared to stainless, Inconel has slightly lower specific heat capacity and, once hot, radiates it away a little slower, but makes up for it by remaining strong up to 760°C (1400°F). By that point, stainless steel would have the consistency of butter. This makes all-Inconel suppressors superior for guns with high volumes of fire, such as machine guns. Future products are planned with Haynes 282 alloy, permitting operating temperature up to 980°C.

TDS is co-located with Volunteer Aerospace, a company that makes internals for space-going rocket engines and other things which must be strong, light and durable. Their main manufacturing method could be described as 3D laser printing. The printer, an $800,000 device the make of which they prefer to keep confidential, deposits Inconel dust in thin layers to be...

This article first appeared in Small Arms Review V22N8 (October 2018)
and was posted online on August 24, 2018


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