Roger Long wrote:
Someone asked here quite a while ago about a sail track lubricator
that could be sent up and down the mast to spray dry lube into the
track. I found myself in need of such a device so I built one.

http://home.maine.rr.com/rlma/TrackLube.htm

Took about 15 minutes to make and worked perfectly. Sail now zips up
and down freely again.

From my very distant memories of childrens' playground slides, candlewax is
the best metal-to-plastic or metal-to-seat-of-pants lubricant. Pity we can't
make sail slides out of same! Try it on your obstinate zip fasteners.

Dennis.