As far as any of us know (=nill) only the best materials like stainless steel (NOT CHROME PLATED "Stainless"), glass, titanium, and annodized* aluminum should be considered safe for use smoking devices. Plus its better to make a piece out of 100% safe materials then "hoping" the shit doesnt get hot enough to poison you. Also brass contains high concentrations of LEAD, COPPER, and TIN which all have low melting points and there for release poisonous ions at even lower temperatures. STAY AWAY FROM THIS SHIT AND DONT SUGGEST IT EITHER! Not even iron or mild steel should be used.

*annodized aluminum has been electroplated with a protective coating that prevents it from releasing toxic ions so you really shouldnt scrape it

It is very difficult to walk the razor's edge with a blind fold.
Be safe for your own sake.