How to pronounce “red heat” in English

He would fill them about 2/3 full of what he called a paraffin spirit, bone oil mixture, and would add in four grams of lithium, a pinch of lampblackfor the carbon because you need the carbon, and then would heat them to a dull red heat for 14 hours, and then set them aside to cool.And, again, I know you're not supposed to have favorite moments, but this is really one of my favorite moments.