[TowerTalk] DIY Air Wound Coils

[Grant Saviers]

One caution with printing any outdoor use FDM RF immersed widget is that 
slicers default to honeycomb internals and almost all FDM printing is 
not watertight between the layers.  Solvent bath or vapor with a plastic 
soluble solvent can help fuse the layers, but may not be 100%.  Full 
density printing can help lower water absorption.

Also, natural ABS is not UV resistant but can be made more so with 
additives.

I've FDM printed a number of coil form designs trying to lower losses, 
but the old AirDux style of notched bars was about the best.  My final 
choice was slotted acrylic bars for strength, water and UV resistance, 
and ease of solvent gluing the wires in place.

Grant KZ1W

On 1/18/2023 04:05, Charles Gallo (KG2V) wrote:
> On 2023-01-18 06:05, Rob Atkinson wrote:
>> QST had an article a month or two ago about using a 3D printer to make
>> coil forms.  Not a word anywhere in the article on the carbon content
>> in the material, or if it's lossy at RF.  First things that went
>> through my mind, especially since the material was black plastic.  I'd
>> put the coil form in a microwave and see if it heats up and see if it
>> has any less-than-infinite resistance.
>>
>> 73
>> Rob
>> K5UJ
> 
> Probably fairly low in carbon - just based upon what I've seen for 3d 
> printers
> The filament is probably one of 3 (well 2 actually - didn't see the 
> article) materials - exact composition is vendor dependent
> 1)PLA - this is an opaque plastic, tends to be dyed (not pigment filled) 
> - I DOUBT this is what was used, as it does NOT hold up well outdoors, 
> but easiest to print, and most common, so I mention it
> 2)PETG - Basically soda bottle plastic.  Most colors are slightly 
> translucent - aka, a dyed color.  Holds up way better outdoors, is 
> stronger, and slightly more temperature resistant
> 3)ABS - Yep, the same stuff pipe etc is made out of.  Much stronger, 
> temp stable, weather stable, BUT harder to print, as it has a strong 
> tendency to warp while printing (Basically you need an enclosure, or luck)
> 
> The filament industry tries to keep anything abrasive out of their 
> materials, UNLESS it is stated it has fillers (Wood filament etc)
> 
> I wouldn't worry too much
>