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Subject kinda says it all. Are we talking 6, 6/6, 6/9, 4, 12, etc etc etc? Thanks

In my opinion, 6/6; reminds me of an unfilled grade I run at work based on overall flexibility.
I haven’t burned it for a smell comparison.
Best I have without an FTIR

Id swear it was in one of their advertisements at some point, I had always heard it was 6/6

Here's a thread also mentioning it from a member with plastics experience https://www.rc10talk.com/viewtopic.php?t=24380

pma1123 wrote: ↑Sat Dec 21, 2024 12:40 pm In my opinion, 6/6; reminds me of an unfilled grade I run at work based on overall flexibility.
I haven’t burned it for a smell comparison.
Best I have without an FTIR

LOL!! I have to be perfectly honest. I haven't a clue about anything you wrote out there!

morrisey0 wrote: ↑Sat Dec 21, 2024 11:57 am Subject kinda says it all. Are we talking 6, 6/6, 6/9, 4, 12, etc etc etc? Thanks

I asked Richard Royal of RPM about the nylon and this is what he told me
Basically AE is using a modified 6/6 with additives for durability. The difference in additives is the difference between RPM and AE 6/6 PA. At least as I remember it.

That's interesting, I wouldn't have thought rpm material had any fiber reinforcement. It's so soft and flexible (which makes it durable, just not race worthy)

GoMachV wrote: ↑Sun Dec 22, 2024 2:58 am That's interesting, I wouldn't have thought rpm material had any fiber reinforcement. It's so soft and flexible (which makes it durable, just not race worthy)

As I understood it's not fiber but chemical

I got the impression from reading that RPM used Delrin (POM) instead of Nylon (PA). Is that not the case?

Quoted myself. D'oh!

Delrin is more rigid and brittle from my understanding while Nylon is more flexible and softer.

HS-YZ250 wrote: ↑Mon Dec 23, 2024 12:27 am I got the impression from reading that RPM used Delrin (POM) instead of Nylon (PA). Is that not the case?

RPM parts are nylon

Adding to the mix here…My guess is they added a rubber modifier (low percentage 1-2% of other “additive” pellets) which is typically butadiene (the B in ABS) on those RPM arms to gain a bunch of ductility/flex.

The Nylon 6/6 family is pretty common group of material for injection molding and a good pick for impact/flex applications that need high strength/tensile. They offer all different flavors within this 6/6 family that would focus on specific things you’d want in an application….UV inhibitors, color, flame retardants (UL), impact, added stiffness, etc.

Material suppliers in injection molding in the last 10 years have come up with new ways to have longer glass fiber lengths in the parts without being destroyed in the process. (Also use of carbon fibers)
It is precisely the recipe to make an A-arm have better impact strength and more stiffness.

As an aside, I somewhat wonder if anybody has kept up with this, or if they just refer to the spec on an old drawing?

Is this the “stuff” that makes certain modern cars handle a skate park session?? Probably

Delrin (DuPont) or Acetal is a hard, smooth material with good surface lubricity, but somewhat brittle/low flex. You’ll hear it called POM also. Typical pick for bushings, but also tons of other applications. Usualky black or white, not the best for impact, but it machines like butter.

Daryls son sent me some of his drawings recently and I finally know the material they used on our A&L wheels and trans cases back in the day

The Zytel ST801 gained the industry trade name “super tough” back in 80’s, totally makes sense somebody would choose that for this demanding application.

The NC010 in the name is their code for natural color (golden/off white).

Im sure modern materials have advanced, but back in the day Daryl said they would mold a few different materials and take the wheels out back to the dumpster and chuck them as hard as they could to see if they could get them to break. The material they ended up with was the one that survived the dumpster test haha.