Originally Posted by PhatRV
There is another thread talking about Proseal turning into mush when the tank is leaking. This gets me worried because I thought the Proseal is fuel proof and the leaking is caused by improper sealing instead of Proseal disintegrating over time. Were you using the 10:1 mix ratio in your build or did you vary the mix ratio to compensate for the temperature?
We know it happens. We don't yet know why it happens, not in the chemical sense. It is not mix ratio; the manganese dioxide is a catalyst, not a component. Full reversion appears to be linked to evaporation of fuel in free air. Some older technical papers suggest a link to the formation of peroxides in fuel.
Most would be surprised to learn there is no mil spec or standard specific to polysulfide sealant use with avgas or mogas. All tests are done with JRF, a standard fluid emulating jet fuel. Does it matter? Clearly the sealant works under normal circumstances, inside the tanks. Avgas is standardized. Mogas is always a wild card.
Entirely aside, I'm not aware of any manufacturer's instruction which suggests mix ratio should be varied for temperature.