# How to determine the time it takes for metals to reach a temp

#### Altrepair

I need to know how to find the time required for metals such as steel and copper to reach a temperature of the environment in which it is placed, based on its mass and the initial starting temperature such as the room temperature. This is important for me because I am going to start up an alternator re-wind business and the directions for the resin clearly states that the cure time does not start until the part has reached the same temperature as the oven it is inside of instead of what the temperature of the pre-heated oven is at.

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#### Danger

Gold Member
Welcome to PF, Altrepair.
I'm not sure that what you want to do is possible, let alone practical. There are a lot of variables, such as the exact composition of alloy, thickness, etc.. Does it have to be of constant temperature all of the way through, or only on the surface?
If time-expenditure isn't critical, I'd just give it an hour more than your best guess to be sure. Otherwise, you can get remote touchless thermometers that might work for your purpose.

#### Altrepair

I only need an approximate formula. Uniformity of temperature throughout the material is not important. The resin has a fairly wide tolerance. It is just that the longer it is at temperature, the harder and more rigid it will become. Rigidity of windings in motor or alternator repair is important because of vibration and heat which kills windings if the resin has not been cured at proper temperature for a specific length of time. I want to have it done in a relatively short time frame without the need of thermal sensors as time is money and energy used is money loss too.

#### Danger

Gold Member
time is money and energy used is money loss too.
Gotcha... I hadn't thought of that. Unfortunately, math is absolutely not my bag. You'll have to wait for someone else to chirp up. Good luck with it.

#### Bob S

I think the time required is something like cooking a turkey; you want to be sure the meat in the center is not pink. Turkey cooking time seems to scale linearly with weight, so it's proportional to the cube of diameter. You could measure the resistance of a winding, because that increases with temperature. Also, a convection oven would speed up the process over a conventional oven. I hope this helps.

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