You usually do not braze copper, you solder it. If you were to use brazing rod on copper, the copper would have very close to the same melting point as the brazing rod. This makes it difficult to do. As far as preheating the copper, it needs to be hot enough for the brazing to flow.
Preheating an oven will cause whatevr your baking to cook evenly
You must use flux while brazing because the flux prevents oxides from forming while the metal is heated. The flux also serves the purpose of cleaning any contamination left on the brazing surfaces.
how to clean or treat copper pan before first use. Does it have some substance on it to keep it shiny that must be removed before use?
Concentrate must be purified and refined before it yields copper that is ready for manufacturing applications.
it must be heated to before it can be made into something because copper is a solid form at room temperature if you were to put it into a liquid for it would be easier to form, such as a square, or a triangle.
It is Must to Preheat your oven (200 deg c) before you cook cake, you will get well cooked cake within 15 Mins
If it is a copper nugget, it must be made of copper.
Preheating an oven means setting a temperature before putting something in an oven. If you don't preheat the oven and put a turkey in the turkey wil be cooked for longer. Which can affect the texture, taste and what not.
Yes, you absolutely may use copper pipe for Oxygen service. There are, however, several things that must be taken in to consideration. First of all, any piping that will carry Oxygen MUST be cleaned in accordance with CGA G-4.1. If there is any oil / hydrocarbon residue in the pipe and pressurized oxygen hits it with any force there is a high probability that the oil may ignite. You should purchase tubing and fittings that are cleaned and bagged for Oxygen service. Second, you need to keep in mind that copper tubing is for relatively low pressures. The pressure rating is also dependent upon the method used to join the copper. If the copper is intended for cryogenic oxygen service, a high silver content brazing alloy should be used. Also, whenever brazing you should have a constant purge of dry nitrogen flowing through the pipe - this will prevent oxidation / scale inside the pipe. After assembly you should pressurize the system with Nitrogen and use a bubbling leak detector that is OXYGEN SAFE to check for leaks. Whatever method is used to join the pipe, you must be certain that there is no contamination (oil, flux, etc) inside the pipe before the system is pressurized with Oxygen.
If you place food in a cold skillet, the food will eventually stick.
Mercury must be collected with a piece of copper dipped before in mercury to form an amalgam on the surface.
Mercury must be collected with a piece of copper dipped before in mercury to form an amalgam on the surface.