How to Get Brass
Brass is the mid-game metal used for Brass Funnels, Brass Tunnels, Brass Bars, Brass Doors, Brass Ladders, Brass Scaffolding, Brass Table Covers, Brass Ingots, Brass Nuggets, and the Block of Brass. You cannot smelt it directly from ore; you alloy it.
Alloying in a Basin
Place a Basin and drop in Copper and Zinc in the correct ratio. Heat the Basin from below with a heated source (a lit blaze burner or similar heat source under the Basin) until the mixture melts into Molten Brass. Use a Spout or a mechanical arm setup to pour the Molten Brass into Ingot molds on a Depot or into a Casting Basin to solidify into Brass Ingots.
Working With Brass
Once you have Brass Ingots, craft them into Brass Nuggets, Blocks of Brass, and the many brass decorative and functional blocks. Brass Funnels and Brass Tunnels are the smart versions of Andesite Funnels and Andesite Tunnels — they can be filtered and configured, so upgrade your Andesite versions as soon as you have steady Brass production.
Scaling Up
Automate the loop: feed Copper and Zinc into the Basin with funnels or chutes, keep the heat source fueled, and extract finished Brass Ingots with a Chute or funnel onto a Depot. A second Basin for a different alloy keeps the line from stalling. Store overflow in a Block of Brass form to save space.