Gas Law - increasing temperature with constant volume held

I've set up a simple experiment to look at the ideal gas laws. My experiment is relatively simple in that I have a metal tube which is capped on one side. I am then pressurising the tube with air to 100 psi and locking it off. 


My thought is that as the pressure increased, with volume held constant, the temperature of the tube should rise. However, after 30 minutes of observation, there is no rise in temperature. Am I missing something? I was expecting to see the temperature of the tube rise. 


The tube is SS 316 with a ball valve capping it off at one end and using the pump to hold the pressure once it is reached.


Thank you.


