GregG wrote:Back when I was still using a Trangia I carried the metho fuel in a one litre Nalgene fuel bottle. I can't remember what brands of metho I used and don't know what extraneous substances were mixed in by the manufacturers but the Nalgene bottle lasted a couple of years and and suddenly went brittle and disintegrated, luckily this happened at home when preparing for a walk so I was not stuck out in the donga without fuel and with metho soaked gear. I've no idea why this occurred but presumably the fuel attacked and changed the hardness/composition of the plastic, but strangely enough metho is sold in plastic containers which seem to have a long life on the shelf. This has nothing to do with your question about MSR containers making the metho cloudy but I just throw it in as evidence of the (apparant) ability of metho to attack some plastics. Maybe ditch the Trangia and use gas?
I've had nalgene bottles in storage degrade, I think it has a lot to do with storage conditions (in a box stewing in various off-gassed chemicals) and just age. Some of this stuff actually gets OLD! It also can depend on the batch and type of plastic, I have had the milky colored PET bottles fail, not seen one of the brown ones fail, and have only had one of the lexan bottles fail due to impact.
As to the OP, another factor for using the trangia bottle, metho will vaporize more, and generate more pressure within the bottle. the Trangia bottle makes it easier to equalize that pressure than a screw-top bottle. Just prevents a little spray, though they will cough a bit out sometimes, its controlled.
One of the aspects of metho in a steel or alloy bottle is that there is nothing in the metho to keep oxygen from attacking the metal. There is no chance of any coating. I have a buddy who found an old (presumably steel) fuel bottle that had white gas in it, he had no idea how long it had been forgotten in the back of a cupboard, 10 years or so was his conservative estimate. Oring crumbled when he took the cap off. There was a ring of corrosion at the level of the fuel, and the fuel was red from the rust which had formed below the fuel line. Who knows the condition of the fuel at the start, or how many hot-cold cycles could have added water to it. Even long term(decade) storage of kero is tough better to use and refresh.