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Which is more durable nylon or phenolic plastic?

Harrycrowther

Plastic
Joined
Mar 29, 2019
Hi everyone

I'm looking for spacers for a printed circuit board. They need to be vibration and shock resistant and non-conductive. There seems to be a lot of nylon and phenolic options available, but I can't find much information about phenolic plastic. Please can you tell me if nylon or phenolic is more durable?

Harry
 
If you're talking about a reinforced phenolic, then use it. If there's any significant loading or shock, it should be almost as robust as the circuit board material, and more resistant to environmental factors (humidity). And you don't have to worry about cold flow.
 
Which type of phenolic? paper or cloth? weave size of cloth? etc etc …………. and that's before we get to the resin type.
 
why not make the spacers from the same circuit board material ?

Because then the circuit board won't work anymore. It's almost as bad at letting the magic smoke out.

Geez, go figure!!

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why not make the spacers from the same circuit board material ?

Because he's looking for an off the shelf part?

Hi everyone

I'm looking for spacers for a printed circuit board. They need to be vibration and shock resistant and non-conductive. There seems to be a lot of nylon and phenolic options available, but I can't find much information about phenolic plastic. Please can you tell me if nylon or phenolic is more durable?

Harry
 
I worked for the Dept. of Defense for 40 years as an electronics tech and we used plastics and aluminum, sometimes in combination, if the traces were too close to the stand offs so that they would not short to ground.
Karl
 
I suppose it varies with the composition of either, but I've seen phenolic gears run decades over what any nylon would do if paired with the same components and run under similar loads.

+1 on this. Do you remember the old GM cam gears? I replaced many of them. Definitely not one of their brighter ideas.
 
Nylon is a good mechanical material when its wet. By wet I mean that it has absorbed water, up to 2.5% by weight. A hot engine environment will dry it out and make it brittle.

Tom
 
+1 on this. Do you remember the old GM cam gears? I replaced many of them. Definitely not one of their brighter ideas.

Yup. That's one example I was thinking of. Between 1968 & 1981 I sold auto parts at NAPA. There were some timing gears in that era that were phenolic. They'd wear out, but seemed on average to last much longer than the nylon junk. Granted, most of the nylon timing sets I dealt with were nylon over cast iron chain sprockets while most of the phenolic sets were spur gears. Nevertheless, it was obvious that nylon was an inferior material for that use and environment.

Another example is the toggle gears on my Sheldon lathe. Barring crashes, the phenolic gears last as long as brass, perhaps longer while others' attempts to use nylon have not yielded good results under heavy use.
 
Nylon may take a "set", meaning that it can "creep" to reduce the pressure on it. That is not much of an issue for a snap-in type standoff, but for a nylon tube with a screw through it, may be an issue in some circumstances. It is a thermoplastic, so the properties, including the tendency to creep, depend on temperature to a relatively large degree.

Phenolic is "thermoset", meaning that it becomes a solid that is much less temperature dependent. So it has somewhat less tendency to "creep", or loosen up if put under pressure.

That said, nylon may be more flexible, and thus "tougher" for impact, while phenolic can be much more resistant to wear. even with moderate impact. (as with the gears) I doubt either of those are important for a printed circuit board, unless you are holding up a heatsink with the standoff.
 








 
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