D.A.M. question...

[Midway Tommy]

Hi Tommy, I stand correcting, teflon, I thought was an aditive they add to grease, such as Cal`s grease, I think the washers you are refering to are delrin, or delron, yes they would work good, cheers Don, good luck Lannie.

Donny ,

I think Acetal, Delrin AF® and (Teflon) PTFE can all be used interchangeably with each to an individual's preference.

[jurelometer]

I definitely wouldn't argue with Tommy about what works in a vintage freshwater spinning reel.  Any variant of the materials mentioned might be good enough with modest drag settings and shorter runs, but these choices are not without consequence in more demanding situations.

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When you buy Delrin,you are getting an acetal homopolymer (POM-H).  If you buy something labeled simply as "acetal", it is most likely an acetal copolymer (POM-C).  Most of the mechanical and thermal properties are within 10% or so, so they are fairly interchangeable, especially in the case of parts made from sheet stock.

You can get acetal with carbon and/or glass fibers to make it stiffer.  But this not needed for drag washers, as acetal has very little creep (permanent deformation under load).  You can get also get it with some PTFE added to decrease the coefficient of friction and lessen the difference between static and dynamic coefficient of friction (less sticky). Acetal absorbs very little water.

Acetal would be a perfect drag material except that:

1.  The max operating temp is ranges from about 170 to 180 F.  It literally gets squishy at 250F.  Acetal blends with PTFE do not have improved operating temperature or melting point.

2.  The low coefficient of friction means that you need much more clamping force to get the same amount of drag asyou would get with leather/asbestos/carbon fiber washers.

I have seen a couple fly reels that uses acetal for drag washers.

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PTFE (most common trade name is DuPont's Teflon) is a different beast.   

PTFE has an extremely low coefficient of friction, with very little difference between static and dynamic.  It is not very resistant to creep, so fiber filled variants (DuPont trade name: Rulon) are usually used for things like thrust washers (or drag washers).  It is very resistant to water and heat(operating temps up toward 500F).  It does have some weird properties like the coefficient of friction decreasing with surface speed (good for a thrust bearing, bad for a drag washer). 

Rulon makes a decent drag washer except it has the same clamping force issue as (2) for acetal, but in a worse way.  Larger fly reels that use Rulon have some difficulty in getting enough drag, and have to stack three or more washers of a much larger diameter in place of a single smaller carbon fiber.

Both materials are not used much in conventional tackle.  Rulon might be a bit underutilized, especially in light drag settings situations where extremely non-sticky drags are highly valued. 

-J