Slightly sticky yellow Delrin

[Dan In MI]

As some of y'all know, I recently acquired a couple of NOS Camillus 717Ys. Both appeared to have a light coating of Cosmolene or similar such on them, and the covers had a slightly sticky feel. They cleaned up easily enough, so I chalked it up to the coating.

Today, I received two Case 3318s from 2012. Their covers also had a very slightly sticky feel. After a quick bit of handling, it's almost gone from the carrier. Come to think of it, my 2021 Case 3137 might have had a similar feel that also abated quickly.

I'm starting to wonder if this is a peculiarity of that material. Has anyone else noticed it, or have ideas as to what could cause it?

[knife7knut]

You might want to isolate those two from the rest of your knives;it sounds like the onset of celluloid out-gassing.A tell tale sign is a brownish film on the nickel silver bolsters.

[Dan In MI]

Celluloid out-gassing is within the realm of possibility, I suppose, but it seems extremely unlikely. The Camillus knives were made no earlier than 1994 (and a Camillus catalog from that year states that the 717Y has Delrin covers). Both of the Case 3318s are from 2012, and the Sod Buster Jr. isn't even six months old. Case, however, only describes these covers as "synthetic." They may or may not be Delrin. According to this article, celluloid had fallen out of general use--and favor--for working knives well before the Cases and Camilli in question were produced.

On a somewhat related note, the Imperial key jack I bought recently has neither a sticky feel nor a brownish film on the bolsters. Hopefully that means that its covers are not celluloid, or at least the celluloid on it is stable. That one is separated from the others...just in case.