Thank you for the reply
The tank is not purchased; it was made in our student machine shop. Assuming I have the coefficient, how would I go on from there?
I'm trying to find a heat transfer equation that includes time. Metal tank, partially filled with liquid. I need to find the time it would take for the temperature on the outside of the tank to drop from θ2 to θ1, given thickness, metal and liquid's properties, and tank dimensions