It _will_ anneal _all_ aluminum alloys, affect many steels, and melt many zinc alloys. You have to be careful what you put in.
You also have to sandblast afterwards to remove the ash. That puts back some of the labor content you didn't need for the burning, and greatly increases the volume and weight of the toxic waste stream you must pay to get rid of.
Reason I asked as I see it as very detrimental to cast iron as well. If 700 to 900 degrees F is okay then simple overheating an engine should not crack or warp a head or distort etc etc.
There's nothing simple about overheating an engine. The heat input is periodic and concentrated, and mechanisms that normally abate the heat have already failed in any of a thousand ways. I see minimal correlation to gradual heating in an oven with circulating air and functioning controls.
In my opinion, if you soak a block and/or heads at 700+ degrees you have just turned it into scrap. I doubt very much that the thing would remain straight.
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
Distortion from heat can be two ways that I know of.
The heat is unevenly applied and unevenly removed so some parts expand more than others creating stress. The stress is then relieved by further heating then the new form is frozen in during cooling.
The heat goes high enough to break down the crystal structure to some degree, then the rate of cooling causes a different crystal structure and shrinkage. The different shrinkage causes warping.
This is all happening in 3 dimensions throughout the part, with the section thickness and temperature gradients all impacting.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
