derin/nylon?

[narked at 90]

now this is a strange one to be asking......so here i go....
I'm in the middle of building a new breather which is going great until now,
I'm now building a new cell holder to take 3 cells,the question is and it may be a stupid questen to you lot but...
i can't get hold of a delrin rod which is what i would normally use but instead have got a rod of nylon..is there any issues with O2 and nylon or pressure problems???
???
hoping i might get an answer before i commit
best regards john routley(narked at 90)

 

[Hootis]

Not aware of any O2 problems, but nylon is hygroscopic (absorbs water & changes form). Delrin is a better choice for parts exposed to water. OSHA, the Navy and other government agencies do not allow acetal (Delrin is a brand name) in breathing loops due to potential off gassing...but it is used frequently by several manufacturers. That being said, I believe that the exposure is so small (expecially at the temperatures we are concerned with) that it is a non-issue. Acetal is very nice to work with from a machine perspective. It's also pretty dimensionally stable with fluctuations in temperature.
Later,
Ryan