There's a useful guide here

Russell.

PTFE, very good for bearings but expensive, has a greasy feel is almost (always?) a off dull white shiny finish and is heavy compared to nylon, acetal, pvc.Bit heavier than Delrin but easy to confuse. PTFE machines very well and takes a good finish with a hss flat or slightly negative rake tool with a stoned radius. Back off drills or they will pull in (same as brass)

Do not inhale dust or fumes – wet polish and grind only

Jopo

Mike .I think you might find though Delrin is a trade name that it has different properties to acetal.
And colours can have an effect on material behaviour ( the dyes do have some impact)..as to nylon…many many flavours…..

BTW – don't be tempted to try burning tests on anything that might be a fluorinated polymer (including PTFE). People have died (Hydrofluoric Acid is VERY nasty and can be formed when these are burned).

..ptfe..don’t we put that on frying pans?
Makes yer think

.

See here, for some thinking

and here, for a typical MSDS

If I recall correctly; there were a couple of cases in the late sixties, or early seventies, where someone accidentally contaminated a roll-up cigarette with a strand of PTFE swarf. This is a very good way of ingesting the products of combustion! … We were certainly made very aware of that risk when I worked at Kodak.

MichaelG.

Colour is usually of minor significance with regard to either properties or identification of polymer type – most polymers can be coloured to any of a wide variety. Some pigments will alter other properties to a degree.

Some companies however may always purchase particular polymers in specific colours to aid internal identification (or to make any bits that fall off show up in the food).

Friction properties can often be modified by incorporation of various additives. The specific behaviour you witness may not be a natural property of the polymer – this can make identification even trickier.

I note with interest Michael's post above which links you US sources.

If you don't have an interest in safety of chemicals don't bother reading ths, it's tedious but as this is my day job I feel I need to contribute to the sum of human misery by a short teach-in.

Regrettable these give a somewhat restricted view of the toxicology of PTFE.(Cas RN:9002-84-0). Congess has recently decided to implement the GHS (Globally Harmonised System of Classification and Labelling) to address shortcomings in the present system,which willin the future require any MSDS to actually provide information rather than generalities. US MSDSs are not valid in the EU.

The relevant EU document is known by the acronym SDS (Safety Data Sheet). These contain specific information conforming to regulation and based on validated testing regimes.The ECHA (European Chemicals Agency) based in Helsinki is managing the REACH system and publishes various pieces of data. If you go to their website **LINK**
and key into the search box the CAS number 9002-84-0 (not forgetting to tick the agreement box you will find the EU Harmonised classification which indicates in coded form the various hazards of this chemical.

Further searches within the ECHA website will reveal the basis of this information; which is backed by peer review. Details of how to carry out such searches are beyond the scope of this post.

I warned above that this was going to be tedious.

In the end the ECHA classification confirms that PTFE is as bad, possibly worse than Michael has indicated.

Happy reading.

Jerry

I hear that PTFE is to be withdrawn from use on the likes of fry pans in the next year or so. Ian S C

Ian S C

May I ask what your references are for the withdrawal of the use of PTFE on frypans?

Jerry

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