Decalin Evaporating

[jiott]

Here's a weird one! I use 95% Mogas without ethanol, but occasionally use 100LL on x-countries. So I keep a bottle of Decalin in the airplane, but actually use very little. It seems that once I break the seals under the caps in order to use a little Decalin, the liquid level in the bottle keeps going down even though I am not using any more and the caps are on tight. I never notice any wetness on the outside of the bottle, but it will almost disappear in a year or so even though I have actually used only a few ounces. What is going on here? Is it evaporating thru the plastic bottle? Anybody else notice this? I have put the bottle in a zip-lock plastic bag but it seems to do very little good.

[Lawdog]

I use a heavy duty ziplock bag and have not had this issue. It does stay relatively cool in the high country though. Do you have a hangar mate?