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I am looking for a plastic which is transparent to radio waves. I want to place my transmitter in a cylinder. That cylinder would be placed in a big RC plane ( whose body is made up of cardboard). I want the plane to be both telemetry, and RC controlled. That cylinder should allow the signals, should be strong and light.
So which material would you suggest and is that material easy to do 3d print?

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  • $\begingroup$ It's unclear what you are asking for. All plastics are transparent to some wavelengths and not to others (think to two food containers that are both opaque to visible light but one is safe for microwave use and one not). What spectrum are you looking at? Also: you should define "easy" (safer to handle? better adhesion? less warping? easier to post-process? ...) $\endgroup$
    – mac
    Jan 21 '18 at 22:56
  • $\begingroup$ I am looking for the 900 Mhz - 2.4 Ghz band. Easy here means safer to handle, lesser warping and easier to post process. Ultimately, what's most important is that it must be strong, RF transparent and somehow shock absorber. $\endgroup$
    – Xeno
    Jan 22 '18 at 3:34
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For the kind of application you are looking for, transparency to radio signal shouldn't really be an issue, so you are more or less free to choose whatever suits your taste better.

Looking at the 3d printed drone community, the 3 most common materials I see being used there are:

  • impact-resistent PLA
  • PETG
  • ABS

This order also match their "ease of use", with PLA being very easy to print even without heated bed, behaving well with glues in the assembly and being easy to paint on. The impact resistance of "though PLA" still doesn't match that of - say - ABS, but is typically considered "good enough" for anything but the propellers.

PETG is tougher. Print relatively easy (stringing and oozing being the typical problems) but it is known to be somewhat difficult to glue and paint. It is also quite dense, so - dimensions being the same - it will weight more than PLA.

Finally, ABS is a classic. It is strong, durable, easy to finish (with acetone) but it is the most finicky material to print with, requiring an enclosure and proper ventilation (the fumes being toxic).

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To second @mac,

For drone usage, ABS will be your pal*. Both tough-PLA and PETG are relatively heavy, which is a disadvantage for flying saucers. Unless you power up and don't care!

  • And I say this as someone who does not recommend ABS for general printing and I don't like printing ABS myself because of the smell, how much it warps, and most importantly the harmful nano particles it releases when printing (yes, all filaments do this, but ABS is on the very bad side of the spectrum).

Note that tough-PLA differs manufacturer to manufacturer - basically it's not supposed to behave like PLA, so you get proprietary blends. PETG is traditionally tougher than PLA, but with the modified PLA, who knows. I have not personally met tough PLA tougher than regular PETG.


SO:

  • PETG if weight is not an issue. It prints well and it's tough.
  • ABS if weight is an issue. It's not easy to print; and make sure it's well well ventilated area (while venting during the print would mess up your print.)
  • Tough PLA if you only have cold bed.
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  • $\begingroup$ Good answer (+1!). A couple of comments though: A) tough-PLA is heavier than ABS, but also more rigid. If optimising for weight, PLA may still be the better option for drone arms especially when using long arms, big propellers, powerful motors or a combination of the three. B) if using ABS, a recommendation would be to print in black or another very opaque colour, as ABS tends to be more sensitive to UV light than other materials. $\endgroup$
    – mac
    Jan 30 '18 at 23:45
  • $\begingroup$ Good point @mac, forgot about the UV here! I tend to go PETG all the way, and my limited experience with modified PLAs has not made me a believer. (I only tried polymaker from the name brands, which others like, so maybe I had a lemon spool...) $\endgroup$ Feb 1 '18 at 5:04

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