Is black steel and malleable iron (both plumbing fittings) OK to use in a smoker application?

[kosmo886]

I am using a smoker and want to add a grease drain to the bottom. I plan to drill a 1 inch hole in the bottom and attach a mix of black steel and malleable iron pipe from home depot to a ball valve so that I can drain. None of this will come into direct contact with food, but the metal will clearly heat up, so I want to make sure there won't be any issues with anything toxic etc. Out of an abundance of caution I am going to put the fitting in a fire pit for a few hours to burn any junk off of them (hopefully). I've done a lot of googling about this but can't find any conclusive answer. Yes it would be easier to just use stainless steel fittings, but I can't find them anywhere.

 

[PolishDeli]

You'll be fine.
Making malleable iron requires heat treatments anyway.
If they have an anti-rust coating, its likely on oil layer.
Galvanized steel you need to be careful with though because of the Zn coating.

Your proposition to burn it for a while, just in case, is fine. It won't affect the composition but it will affect its microstructure and therefore its mechanical performance. It'll still work for your intended purpose. But don't use the fitting for its manufactured purpose ever again.
You can also add a surface treatment. High temp paint, cast iron pan-type seasoning, or smoke soot.

 

[TH-n-PA]

What he said. ^^^^^^