Re: Fuel canister adapter???

Did a little more checking on this.  Apparently not illegal per se,
but trans****ting the result on any road is consequently illegal.

The reasons given that these things were pretty much disposable were:

1) The valves aren't made of the most durable materials.  They're
known to leak as you found out.  Continued attempts to refill may
result in complete failure.

SM: Leak check just means to fill the valve with water and see if the 
propane is bubbling out. What you don't need, more water in the valve.

2) The cylinder steel isn't terribly corrosion resistant.  Refillable
canisters are.  Refill propane contains enough oxygen and moisture to
cause corrosion from the inside out of a disposable cylinder that was
factory filled with dry propane.  I've seen rust on the outside, but
that's usually OK since you can usually tell if it's minor.

Sm: I've not heard of dry versus wet propane. Nor oxygen in the proapne. 
But, who can tell?

3) They get easily overfilled from a higher pressure tank.  Some
people seem to chill the disposable cylinder first to aid in the
filling.  Might induce thermal stresses on the valve as well as expose
to moisture in the freezer.

SM: The instructions do say to chill the tank before attempting to fill. 
"higher pressure tank" is necessary. By chilling the small tank, you
reduce 
the internal pressure. Then, the propane travels from warmer (higher 
pressure) to colder, with lower pressure. It's necessary to invert the 
source tank, so you're feeding liquid. And then weight the tank you just 
filled, to see if it's properly or over filled.