What about if I wanted to put an aluminum grate in a bbq to hold the charcoal? I don't know what temperature it begins to off gas.
The melting point of aluminum is around 1200 degrees Fahrenheit, charcoal does get pretty hot, however, cooking charcoal isn't even 100% pure (meaning it isn't going to get as hot as it potentially can, the reason why it's used for cooking) so there's a fat chance you'll be anywhere near that
The charcoal on your bbq will give off toxic CO which is why you use them outside. Compared to that the Al is no problem but I would have thought that its a poor choice in that application because its too soft.
I disagree w/ the other answer that says you will not approach the MP of aluminum w/ a charcoal fire. Aluminum is too weak for use in this application - that's why BBQs are typically made out of steel. I don't believe you have to worry about aluminum vapor, but rather weakening of the metal and a physical collapse of your cooker. According to Wikipedia, aluminum melts at 660C, and a charcoal fire is rated at 750 to 1200C. Even at the lowest end of that range, one exceeds the MP of aluminum.
