PTFE etc adhesive

[The Natural Philosopher]

Well you could try fried egg. That alaways sticks to non stick pans along with bacon ...

Or just sandpaper the thing

[The Natural Philosopher]

yes amd no.

Glues work in many ways. For example some glues penetrate the surface of things, and thereby create a mechanical bond to porous surfaces with the glue line itself being the final linkage of two parts. A good white carpenters glue joint is of this sort.

Other glues react chemically with the surface to essentially 'weld' the parts together: This is typical of plastic glues and cements that contain the specific solvent for the plastic. solvent weld plastic pipes are typical here.

And finally there are glues that work pretty much by suction. There is no bond, but air pressure and the elimination of air in the joint pretty much holds things together.

I have done that with car body f8iller and polythene. Its not a total bond, and you can tear it apart, but it does stick. Also white glue and plastics.

And indeed epoxy.

The key for using these 'glues that don't really stick' is to create as much surface area as possible. So acid etch, or chemical etch, or roughing up the surfaces with emery or wet and dry helps enormously.

Then what glue you use is not that important: its not penetrating the surface, nor is it chemically bonding to it. Its just there to fill the gap and the micro-roughness of the surface and get rid of the air.

hot epoxy to make it runny - or hot glue - all work.

PVA is good if one of the surfaces is porous and will suck the water out, otherwise it takes ages to dry.

[Andrew Gabriel]

It breaks down well below its melting point. The breakdown products are toxic, in particular they are extremely toxic to birds, and it's often recommended not to have any teflon cooking pans in the house if you have a bird. There's been some suggestion recently that the breakdown products are also extremely toxic to unborn babies, although that isn't universally accepted. Don't overheat a teflon pan - max safe temperature is 240C.

[stuart noble]

Interesting. I was about to test that for fixing pvc panels to plaster

[Mike]

I have used this recently and it glues some plastics really well; I have repaired an old calculator with it. It doesn't glue polypropelene very well, but I'm still experimenting with it. I very much dobt that it would glue teflon.

The worst thing about it is the smell, it stinks to high heaven; Have to mix it, apply it and leave it to set outside the house overnight, even then it still pongs a bit, but this does reduce afterwards.

Re PTFE. Us astronomers use it in thin strips as bearings on Dobsonian telecopes and we either pin it in place or buy 'etched' PTFE which apparently will then take glue successfully (though I haven't tried this myself yet).

See 'etched virgin teflon' here:

[Amazing telescopes].

A DIY method of etching teflon is here:

[you could then ask people to come upstairs to see your etchings]. :-)

- Mike