One-way air valve to stop methanol evaporation...necessary or no?

[Rice Over Wheat]

Most people running meth kits have a reservoir tank that has a pinhole in the cap or elsewhere to allow air in to displace the water/meth as it is pumped out. I haven't heard of this discussed much, but meth evaporates so I'm thinking that over the course of a few days, a 1.5 gallon tank would lose its methanol content. So I'm thinking of putting a one-way valve in the cap so only air is drawn in. Any idea whether this should be sufficient to prevent methanol vapor escaping and the type of valve I should use?

 

[Defiant]

Not needed. You're not running pure enough methanol to be concerned with. You must have a vent, or you'll crush the bottle.

 

[Rice Over Wheat]

I thought that a one-way valve like those for fuel tanks wouldn't require pressure to allow air to pass through but wouldn't let vapor out. But you're probably right and maybe that's why I haven't seen this come up before.

 

[Defiant]

Gas tanks are a much larger volume, and have to deal with the fuel being heated up by the engine and returned to the tank. Much more expansion and contraction going on.

 

[eclipsegsx1736]

I've wondered about this as well. I'm using pure meth, though (M100). A small amount of it will evaporate very quickly.

 

[Rice Over Wheat]

This weekend when I go get some pure meth to increase my mix ratio I'm going to experiment...I'll pour a bit in a cup and tape a lid to it with a tiny hole to vent. Since it'll be 100% meth I'll mark down how much evaporates at different lengths of time. That should give an answer to this.

 

[Defiant]

Methanol is remarkably hygroscopic. It will draw in water moisture from the air, and very quickly.
Ever pour water and alcohol in with one another?

 

[90gst_sean]

I have searched this topic because I am more and more convinced that methanol is in fact evaporating from my reservoir. I believe part of the problem lies in the fact that I use a fairly large 4qt container that can be left to sit for weeks at a time. (40/60w)

The methanol loss was brought to my attention do to detonation showing up in tunes that originally were knock sound. This seems to happen when the methanol mix is left for a protracted time and is not fresh.

I may also look into some sort of check valve for my bottle.

Thoughts?