0.1mm soldering iron/tip

You won't find one, it's impossible to coat a tip that small with iron etc. so that it'll last. 0.4 mm is the smallest made by Metcal. You could always file down a standard tip to get the width you need, but it won't last long.

Leon

I doubt you can get them. Anyway, even such a fine point, when dipped into tin becomes wider. The point in soldering such fine structures is to have two helpers, first the solder mask which repels tin from the surface and second flux gel or such that increases the surface tension of tin plus it bubbles when heated.

Rene

The coating will be destroyed though! And then you're left trying to push around globules of solder. :-(

I have a cheap Antex 'C' iron (15W unregulated). A 0.12mm conical tip is available for it (cpc order code AN107). This tip is "available in unplated mallory only". I've not used mine very much and it's already eroding significantly. Might be worth investing in "Savbit alloy" solder to use with it (which contains disolved copper and is said to reduce erosion.)

Mike.