Solder with some iron in it can be inductively heated and allows you to control were it ends up more precisely. It also creates mechanically stronger tracks because the metal is magnetically aligned.
Yale University scientists have developed a magnetic solder that can be manipulated in three dimensions and selectively heated
[
opa.yale.edu]
Regards,
Erik de Bruijn
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Ultimaker.com] - [
blog.erikdebruijn.nl]