maxi-model
UK/US/ROW steam narrow gauge railways 1:1

Some white metal WILL melt in boiling water!!
Yes. Things can get pretty warm around the smoke box and its door. The burner is pointed right at them. I have seen soldered surface mounted parts coming adrift after a burner blow back into that area. Stick to brass, steel and iron. Titanium if you are feeling a bit flush. Max