ModelCalcs.uk
Soldering Calculator — Temperature & Tip Selection
Choose the right soldering iron temperature and tip size for model work.
How We Calculate This
Recommends soldering iron temperature, tip size, solder type and flux based on your task, joint size and material. The Temperature Tolerance option sets the ± workable band shown around each recommendation. Temperatures are tip set-points for a temperature-controlled iron: 60/40 tin-lead melts around 183-188°C, and the tip is run well above that (melt point + ~50°C + heat losses into the work) so the joint reaches wetting temperature quickly.
Temperature Guide
- Brass etch/PE: 300-360°C depending on joint size
- LED / wire: 280-350°C
- Nickel silver: +20°C above brass — it conducts heat poorly (~25 W/m·K) so the iron must do more of the work
- Copper: match brass — copper is the strongest heat sink (~400 W/m·K vs brass ~110), so for equal joint mass it needs at least as much heat; thin copper wire still tins easily because its mass is tiny
Frequently Asked Questions
A temperature-controlled iron with 15-40W is ideal. The Antex XS25 or Weller WE1010 are excellent choices. Avoid uncontrolled irons as they can overheat and damage small parts. A fine (1mm) tip is essential for most model work.
Lead solder (60/40 tin-lead) is easier to work with and melts at a lower temperature. Lead-free solder is safer but needs higher temperatures and more skill. For model making, lead solder is generally preferred. Always wash hands after handling lead solder.
Flux cleans the metal surface and helps solder flow into the joint. Without flux, solder balls up and does not bond. Rosin flux (in cored solder) is adequate for copper wire and LEDs. For brass and nickel silver use a phosphoric-acid liquid flux such as Carr's Green or Yellow label — not a zinc-chloride "killed spirits"/plumber's flux, which is far more corrosive and harder to neutralise on fine etched parts. Always neutralise and clean off excess phosphoric flux with water or IPA after soldering.
Solder metal parts before attaching to the model. Use heat sinks (crocodile clips) to draw heat away from nearby plastic. Work quickly — touch-and-go technique. Let joints cool before handling. Pre-tin parts separately, then join with minimal heat.
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Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.