8LMM Mortar Baseplate M-3 Pad Test.

Various organizations, including Viet Nam, have reported problems involving seizure of the socket to the baseplate. The testing program discussed in this report was initiated in an effort to solve this socket seizure problem. Three materials were tested the previously standard Neoprene the current standard Viblon and Fluorglas. Testing of these materials included static compression tests soak tests and pressure cycling tests. The compression tests showed Fluorglas capable of withstanding the greatest compressive load 20,000 psi and possessing the lowest recovery rate .001 in.hr.. Soak tests in various environments revealed that Fluorglas suffered no apparent expansions or softening in any of the five media tested. The other materials suffered varying degrees of damage. Most of the effort was spent in hydraulically pressure cycling the three materials, cycling loads equivalent to impact loads during firing, while they were subjected to various foreign matter environments, i.e. dirt, sand, etc. The result of the three tests conducted was that Fluorglas seemed to hold up better in general than the other materials and was therefore recommended as a fix to the problem.