I dont want to bring up a very old and long thread started by PC2K, so i'll start a new one.
In that thread it was debated on how to heat seal straws containing vaseline impregnated cotton wool. In the end no one came up with a satisfactory approach. How about just sealing it with electrical tape?

I too was sceptic at first. But practice is the only way to find out ...
I try to keep things simple :I just heat the straw (stolen at McDonnald's : they are large) with the flame of a BIC lighter and clamp/seal that end with my Leatherman pliers.
Looks like a good seal.
I am just waiting for better days, to leave such a piece of straw laying in the sun, to see if there is any vaseline leaking ...

sealing them with electrical tape will work, ofcorse.
i don't put mine vaseline+cottonwol tinder in straws, i find it hard to stuff it in the straws and harder to pack in a PSK, you can't squize them in tiny little space's left in a PSK, like the linyard hole and some portians of the air chamber of a whistle.... what you can if you don't pack them in something at all. And yes, the contents will get a little vasline on them, but does that matter? Not to me. Weather mine knife got a tiny amount of vaseline on them or not, its stil able to do it's job. just keep the stuff you dont want any vasline on them clear from the tinder.
i used to pack mine tinder in paperpackages ( waxed paper ). worked fine, untill i start using up the space in mine PSK..

just mine 2cents

Doesn't the cotton wool catch fire from the lighter?

*deleted* wrong interpetation of q.

It doesn´t if you take care that no cotton fibres are in the opening. You should also hold the opening up. The straw should be about one inch above the flame.That way the plastic warms up slowly and will stick together when you press it. It will only seal the straw if the the inside gets warm enough to almost melt.

Sorry, I didn't explain properly. I meant wouldn't to cotton catch fire when you seal up the straw with a lighter.

Well, Max is right.
Anyway, you have to be careful. Seal your straws over a place (i.e. sink) where you can drop it aflamed, just in case .......
I didn't have any problem preparing mine, and I plan to make some more this afternoon.
Last time I (almost) catch fire myself, was when in high school, I played with aluminium and sodium peroxyde : adding water to that mixture produce a nice fiery flame. I tried to put this preparation inside a small envelope I had made out of glued toilett paper. Everything was working fine, except, after a few minutes, it catches fire, right under my nose ..... <img src="images/graemlins/crazy.gif" alt="" />
I had just forgetten that there is some water in the glue .... enough to start the aluminium - peroxyde reaction !!!!
Hopefully, I was wearing glasses, so my eyes were protected. I only loosed a few hairs and eyebrows....
A short time after that, I quit chemistry for electronics ... <img src="images/graemlins/grin.gif" alt="" />

Take care.

Alain

you were right about the cotton not catching, but I over estimated the amount of heat it would take to make the plastic sticky. I held it about 3 inches above the flame in it instantly melted back about 3 mm (excuse me mixing metric and imperial) It worked non the less
thanks

Melting and pinching the straw was only step one for me.

I then dip in "plastidip" and let each end dry. So far, no leaks.
(plastidip is magic stuff guys! You can "rubberize" knife grips, xacto blades, rope ends, etc.)