neff oven lamp

Now that problem is an automotive one as well.

I wouldn't worry too much about 'food safe' - you are not cooking food on the glass - but look for some kind of 'anti-seize' . Oils and greases will break down and make things *worse*.

You need something loaded with a soft thread filler that will take the temperature

e.g

Buy a proper cover removal tool. Works atreat.

Maybe just refit it as loose as you can - certainly don't tighten it firmly with the tool.

Looks as though the OP did?

I would be reluctant to use anything that has the slightest chance of drying up and acting as glue. There are some dry lubricants designed for high temperatures. They tend to contain be molybdenum disulphide.

I would fit by hand, tight enough it doesn't move but not so tight I can't undo it. You can still use your tool if it becomes stuck at a later date.

Do you screw it on tight then back off by a 1/4 turn? That should help. Failing that, molybdenum disulfide is a high-temp lubricant. It has very low toxicity in case you are concerned, but graphite powder should also work ok, and that is safe.

See link posted by OP.

Tim

Copper grease? You’re not going to be eating it.

Tim

Yes, I did, it helped a couple of years ago when I couldn't open it by hand, or with rubber gloves etc, but this time it just kept slipping off the ribs.

This sounds like the stuff to use, but I see it sold in qty 3 or 12 tubes, which is several lifetime's worth

Didn't want it melting and fans blowing it around on my food

MSDS says it's a polyalphaolefin oil with fillers of talc, chalk and titanium dioxide

It may claim to be high temperature but the base/thickener is Polyalphaolefin, which has a maximum service temperature of 140C.

It's going to dry out and likely act like glue.

With an unknown temperature range? It's going to dry out leaving the inorganic residues, though I guess TiO2 is known for lubricity.

not interested in eating those either. You do realise that polyalphaolefin oil is the basis for all synthetic car oils?

The datasheet says up to 450°C

My coffee machine "grease" is silicone based, how does that fare above 200°C

I thought more or less every white thing contained it?

Yes

Silicone grease. You just want to fill the voids so nothing sticky can get in.

Silicone grease combines a silicone oil with a thickener. The thickener varies but if mineral based it will slowly disintegrate above 200C.

Just looked up Polydimethylsiloxane, the typical silicone oil used and some sources say a temperature range up to 150C, others suggest 300C.

This paper gets quite involved.

Few turns of PTFE tape perhaps (needs over 300 deg to melt)?

I'll try that with some of the 'thick' gas tape, failing that the silicone grease says it is good to 250°C

PTFE is only good to 260°C

I am not sure that anything carbon or silicon based will not eventually degrade at that temperature: the benefit of copper loaded muckite is the copper at least stays to fill the gap avoiding fat vapours from condensing there

Hmmmm

An animal study conducted in 1955 concluded that it is unlikely that these products would be generated in amounts significant to health at temperatures below 250 °C (482 °F).[33] Above those temperatures the degradation by-products can be lethal to birds,[61] and can cause flu-like symptoms in humans (polymer fume fever),[62] although in humans those symptoms disappear within a day or two of being moved to fresh air.[63]"