Re: RV Antifreeze
Reply #7 –
The joy of a 50% mixture of water and ethylene or propylene glycol is that it turns into a slush first.
The science of the whole thing is that water's densest point is 4° above the freezing point. This coincides with the point of greatest expansion after that as water cools it keeps shrinking.
From the internet via Mr. Google:
"Water freezes at 0°C (32°F) and pure ethylene freezes at -13°C (8.6°F), but mixtures of the two freeze at lower temperatures. For example, a 50/50 mixture by weight of ethylene glycol and water freezes at -36°C (-33°F)."
"Pure water freezes at 32° F, but a 60% solution of DOWFROST propylene glycol pushes the freezing point down to -60° F. While the freezing point of pure glycol is only -39° F, the synergy between glycol and water results in a much lower freezing point."
Fun fact: Once water reaching freezing temperature, it still has to give up four more degrees of heat before it freezes. The same goes for warming ice, once ice warms to the melting point it sits there and keep soaking up heat for four more degrees before turning back into water.
Topic: RV Antifreeze