I have a 38 AWG wire that I need to insulate, without making the overall thickness of the insulated wire more than 25 AWG. The current that will go through it is 9V DC-current. What’s my options?
What is the wire made out of? If aluminum, you can also just anodize it. Outside diameter will change very little; although, the area of the conductor will decrease by the amount of aluminum oxidized. Of course, the anodized layer is quite thin.
Something else to consider is small bore PTFE (Teflon) tubing. Thisis 0.012 ID with a wall of 0.009 = 0.030 total. There is a process called "hardening" whereby one stretches Teflon tubing until the resistance to further stretch increases greatly. It is usually about 3x to 4x longer, and of course, the ID and OD change. accordingly.
I suspect you could easily get from 0.030" OD to something of about 25 AWG (0.0179") . That is a common procedure.