The construction of the SoLID HGC requires a vessel that can withstand pressures of 1.7 atm, or 22.0 psi (absolute) for long periods of time with minimal leaking. These tests sought out to find a method of sealing the vessel so that it doesn’t leak. The vessel was sealed using DOWSIL RTV 832 Sealant. When using a good technique to apply the sealant, the vessel’s leak rate was as low as 5.6×10-4 Torr·L/s, or 2.2×10-6 g/s when filled with C4F8 gas. This result is from test 6 where vessel was left inflated for 28 days. The RTV sealant performed well, but the performance depends on how well the sealant is applied, so there may be better methods of sealing the vessel.