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Title: black Nylon Post by: aa5wg on July 19, 2011, 06:29:19 AM Hi to all:
Is black nylon (i.e. washers, nuts and bolts) a safe material for use at HF and high power. i.e. building RF coils for antenna tuners. Chuck Title: Re: black Nylon Post by: kg8lb on July 19, 2011, 07:43:51 AM Black Nylon ?
Sure looks good with short skirts and high heels. However, not real good in RF fields. Ok as fasteners etc depending on use/location. Delrin (not delrOn) is a better choice. Title: Re: black Nylon Post by: Ralph W3GL on July 19, 2011, 04:12:20 PM Chuck, to do a quick check of the nylon hardware for use in an RF environment stick a sample of what you want to use in the microwave oven for a few seconds at full power :o :o. If the sample gets warm it is no good for the job... ::) ::) Title: Re: black Nylon Post by: kg8lb on July 19, 2011, 04:58:48 PM Nylon is hygroscopic so the reaction may vary with moisture content. (From some reports) Delrin is a more stable material. Although it looks a lot like Nylon it is a totally different material.
Title: Re: black Nylon Post by: KL7OF on July 20, 2011, 10:54:07 AM Black Nylon ? Sure looks good with short skirts and high heels. However, not real good in RF fields. Ok as fasteners etc depending on use/location. Delrin (not delrOn) is a better choice. I like the ones with the seam running down the back Title: Re: black Nylon Post by: kg8lb on July 20, 2011, 07:41:22 PM Black Nylon ? Sure looks good with short skirts and high heels. However, not real good in RF fields. Ok as fasteners etc depending on use/location. Delrin (not delrOn) is a better choice. I like the ones with the seam running down the back Yep ! Seriously though , I repeat: However, not real good in RF fields. Ok as fasteners etc depending on use/location. Delrin (not delrOn) is a better choice. Title: Re: black Nylon Post by: W7TFO on July 20, 2011, 08:05:47 PM To get to your original question, commercial RF inductors are held together with nickle plated brass or stainless hardware, and have washers of fiber, porcelain, or plastic in between so as to not make a connection across the coil end supports.
Those supports usually are of aluminum strap and form a triangle or square to hold the turns spacer bars in place. The same bolts usually pierce the turns spacer material, and this arrangement makes for secure construction with no eddy currents. These bolts do not form part of the RF current-carrying metal, as that is usually a separate fastener thru the turns spacer bar holding a soldered lug from the end of the coil. Where you get into trouble is making RF go thru ferrous hardware and multi-metal joints. Use plated brass or stainless for that, and don't worry too much about support hardware getting too hot from induction. Most of it will be too small to react to the field. Don't use plastic hardware for any job that must stay torqued, such as that carrying RF across a joint. 73DG Title: Re: black Nylon Post by: aa5wg on July 22, 2011, 10:31:23 AM DG and all: AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Thank you for your helpful information. Chuck |