I have a charbroil bbq and it seems like it is sand cast. It seems too light for cast iron and I don’t thing Aluminum can handle the heat. Is it Zinc? Any suggestions for the process andf material would be appreciated.
Mark
Zinc or pot metal (a low grade zinc alloy) is definitely out, because it’s melting point (around 420 C) is much lower than aluminum’s (around 660 C).Most barbeques these days are made with a stamped steel bottom, and either an aluminum top, or a stamped steel lid (if your lid is around 1/16 inch thick, it’s steel, otherwise, it’s aluminum).
According to the experts at Barbecuen.com:
During the grilling process you are cooking at high temperatures, often in excess of 700 degrees, directly over the heat. In barbecuing, the heat is not directly affecting the meat. The heat is raising the temperature in the cooking chamber where the meat resides. Proper barbecuing temperatures are 210 degrees to 225 degrees. This is the optimum temperature for prolonged barbecuing.
Now this is where things get tricky.
The coals are 700 degrees, but the aluminum lid of the grill doesn’t get that hot, because it’s such a good conductor. It can pass the heat from the inside of the barbecue to the outside without having to build up too much temperature to push it. That’s why heat sinks on computers and amplifiers are made of aluminum. Secondly, even if the lid got up to 660 C, which it could, if you were cooking like crazy, it would still have to overcome the “heat of fusion” to liquify (see link below). Since you definitly aren’t producing, or retaining enough heat, you won’t have any problems.
Having melted aluminum with charcoal myself, let me tell you what your grill would need in order to melt down:
- More fuel. (when we did a .75 liter melt, we used almost 15 pounds of charcoal to heat the furnace and metal)
- More oxygen. (we used two industrial squirrel cage fans to force air through the charcoal and make it burn faster and hotter. The exhaust hole shot flame like a jet.)
- More insulation. (to keep as much heat as possible, we made a furnace shell out of a steel trash can lined with 4 inches of cast concrete-pearlite insulation.)
Given that your grill probably doesn’t have hairdryers hooked up to it, I’d say you’re allright.
If you want some more information on the the following, go for it:
Barbeque:
The difference between heat and temperature:
http://id.mind.net/~zona/mstm/physics/mechanics/energy/heatAndTemperature/heatAndTemperature.html
An explaination of heat of fusion
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase2.html
Making your own aluminum castings
http://www.backyardmetalcasting.com/index.html
Thank you for the info. The part is Al. I did also more research and discovered that while coals burn too hot for Al. it is poossible to use al in propane senario with plenty of space around, and the abilty to limit the heat output from propane.
Mark