Wow...very nice compass! And the averall painting it's amazing Jacek.
About squiggles... i painted them randomly with gum metal color not taking to much paint in the brush (i didn't want any paint bumps in the cooling) and then after the paint dried i used the dry brush technique with silver color to soften the colors a bit.
You may see how it look in my presentation thread, there's a Fokker E.III there. Anyway that was me! Maybe someone may tell you other way of getting those done.
Cheers