Topband: Insulator problems

[Bill Wichers]

Delrin is a trademark for acetal. Acetal is the generic name so you'll have a lot better time finding acetal most likely.

My recommendation is to get the *black* acetal as it will hold up much better in UV outdoors. It machines easily, but it's a lot harder (and stronger) than nylon. Acetal can be comparable to some mild metals in terms of strength so it's great for bearings and clamps where you need a non-conductive material.

Also, someone mentioned using polycarbonate (lexan). There's been a lot of interest in that material since QST ran an article about it a while ago but it's not always the best material to use for everything, and it's not the only machinable plastic. If you do use it outdoors you should try to find a UV-stabilized variant. For most other plastics just try to get them in black since the black pigment commonly used will also generally provide improved UV resistance to the material. 

My personal recommendation for most outdoor insulators that will be subjected to any amount of mechanical stress/strain is to use black acetal. It's readily available in sheet and rod stock, and the rod is a good starting point for most insulators. You can find small pieces on ebay or you can get it from most commercial plastic supply houses.

Teflon, BTW, is probably not a good choice since it is not very durable mechanically.

  -Bill


> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of
> Greg - ZL3IX
> Sent: Saturday, December 14, 2013 12:10 PM
> To: Topband Reflector
> Subject: Re: Topband: Insulator problems
> 
> Many thanks to everyone who commented on the above.  The consensus is
> that nylon is a particularly bad choice of insulator for high field environments,
> even on Topband.  Tomorrow I will be looking for an alternative that is
> available here in ZL.  I think Delrin will be the choice, if available.
> 
> 73, Greg ZL3IX
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband