I noticed some spitting during injection, which is why I added the vent holes.
In my opinion, the gas spat from the annular gap between the tip and the body of the can.
I think the reason may be decreased elasticity of a seal in the valve after cooling in the freezer.
I received my thermos, but im afraid there may be a snag. the top metal lid has a plastic ring/inside cover, as you can see here
View Image
the plastic inside is polypropylene, marked by a #5 PP. It appears I might be able to pry the plastic shroud off, but this would take the threads with it as well, meaning the remaining metal lid would not fasten correctly.
Here is the thermos itself, View Image
Should I return it and continue my quest or is this somehow suitable for the application?
Would this work?
1-Freeze all componets (material, column, etc)
2-Pack column as usual and use 1-2 coffee filters
3-Drill two holes in fill cap, one for butane & one for equalizing pressure
4-Press column down on Pyrex so that it would cutoff/impede flow of butane out of bottom of the column
5-Lift column and use bike pump to flush column