1.
If you are using a 55% antifreeze solution (-50̊F nominal protection) in PVC (plastic) hoses or pipes, remember that the burst point is actually only about -15̊F.
An antifreeze fluid that protects to -50̊F, means that a copper pipe filled with that product will burst at -50̊F.
However, the actual solution will start to form ice crystals at approximately +12̊F.
As the temperature drops, the solution continues to form more dense ice crystals and expands. As the solution expands, it puts pressure on the pipe; and at -50̊F the copper pipe will burst.
Because they are not as strong as copper, PVC hoses & pipes, thus protected, will burst at about -15̊F.
2.
When winterizing your Engine, remember that adding antifreeze must be done with the engine totally warmed up and the thermostat OPEN.
A closed thermostat will not allow the antifreeze to enter the block or heads. This means the antifreeze will go through the manifolds and out the
exhaust, leaving the block and heads completely void of any antifreeze.
3. Vodka is mixture of water and ethanol. Pure 80 proof (40%) vodka will freeze at approximately -20F (-29C) - roughly equivalent 45% glycol.
You’d have to fill your water system with ONLY undiluted Vodka to achieve freeze protection.
In addition to propylene glycol, a good antifreeze will contain a number of additives (lubricants, PH stabilizers, &
corrosion, scale & algae inhibitors).
See also
Chuck Husick on Antifreeze
(Techno-Talk, May 2006 from BoatUS Magazine)
Goto: Chuck Husick on BoatUScom
And numerous other
Winterizing tips from BoatUS:
Goto: BoatUS.com Winterization Tips