fandi

Fandi is transitive and it means to liquefy something with heat. The Reta Vortaro's own list of objects is a good one to memorise, because it settles the scope in one line: fandi metalon, vakson, buteron, neĝon - to melt metal, wax, butter, snow. So this is not a metals-only word, whatever the foundry connotation suggests in English.

Three senses sit under the one root, and Esperanto does not split them:

1. melt - la suno fandas la neĝon
2. smelt, to get metal out of ore by melting - el ŝtono oni fandas la kupron
3. cast, to pour the molten metal into a mould - li fandis kvar orajn ringojn

Transitivity matters here, as it usually does in Esperanto. Fandi needs an object: something melts something else. When the thing melts by itself you want fandiĝi, with the -iĝ- that turns an action round on itself: la vakso fandiĝas de la fajro, the wax melts from the fire. Getting that pair the wrong way round is the single commonest mistake with this verb. A fandejo, with the place suffix, is a foundry.

The false seam. There is no -and- suffix in Esperanto. Learners who have met Latin gerundives, or who have just drilled the genuine suffix -end- (pagenda, needing to be paid), can see f- plus -and- here. They should not. Fand- is one root and nothing comes apart.