One of the first things I needed to build was stabilization for 40mm devices. There are many options out there but I needed something that could be constructed quickly, would be safe if there was a catastrophic failure and that could be duplicated quick, welcome to the world of 3D printing. The key elements in the design are that it had to be able to absorb the force of the lift charge, had to be manufactured in a way as to be able to break apart without throwing large pieces of debris if there was a failure and also had to be fire resistant.
In this post I will talk about how I built these, tested them and how I achieve the desired goal. You should always put more than the minimum required distances required in NFPA1123, to ensure that if there is a failure that there is no chance of injury. People seldom realize that we put these distances requirements in place because we have years of experience dealing with energetic materials and we want to ensure the upmost safety of our customers and clients. Recently I cancelled a booking because the folks organizing the event thought they knew more about energetic materials that I did. So like everything else, we ensure safety first and if we can't get the minimums required we don't do the shoot.
Goals of this design
Handling catastrophic failures
By incorporating brittle break points, if there is a catastrophic failure the holders should break and the designed break points. In short there are weaknesses built into the design to ensure that it breaks cleanly and evenly, in the event of a failure the design should break into 2 pieces.
Dealing with lift charge forces
By creating a honeycomb design in the base, the thought is that it will withstand lift charge forces. Testing has shown that it is adequate strength, and just like any other devices, they should be inspected for cracks, deformities and other damage prior to use.
Dealing with fallout, sparks and fire - there will be fire!
This challenge was probably the biggest issue to solve. We have solved it by using silicone coatings on the holders. This silicone makes the devices fire resistant but not fire proof. Just like your Cobra silicone boots, they will burn if they get hot enough, they will melt if they get hot enough and they will deform if subjected to long term heat. So in short nearly all materials will melt or deform if they become hot enough, but the silicone coating makes them less likely to catch on fire or burn. Not a total solution but not unlike other pyrotechnics products on the market.