got the job, now the randoms begin- need advice

so, i landed a job that does random testing. i have been reading up on how it usually works and just want to be the best prepared i can be...
i have heard that random testing is usually quarterly and your name is picked randomly, once picked your name goes back into the pool and you could get picked again OR rarely, just depending on the luck of the draw.
my plan is to always have on me a bottle of QF, digital thermometer and two heating pads.
my questions are... appx.how long does a bottle of QF take to get up to temp just using body heat and the heating pad? i will be practicing... my last little hottie that came with the QF barely stayed warm for an hour WTF? so, i ordered dif heating pads.
also, do you really need that initial boost from the microwave- i might not have the chance for that.
has anyone ever really overheated their QF just from the heating pad?
also, when you get pulled for a random do you have to go immediately or after work that day? i don't have a car, so will carpool to work and if i got pulled for a random test midday am not sure how i would get there- it would suck if the supervisor drove me.
thanks, any advice is greatly appreciated:hippy:

I had a job where all of us were ordered to take a random within 24hrs due to a suspected thief among us and we were allowed to go alone.The heat pad that came with my qf 5.7 seemed to be inferior to the hand warmers I buy now at my local 7-11 or gas station mini mart (pkg with 2 costed $1.29) and they are bigger and work great.Without access to micro or a car defroster maybe a hot coffee or if you could go in a bathroom and run the hot water on it until its warmer then add heat pad and crotch it.

thanks for the suggestions. i did a little experiment today and just crotched it w/o a heating pad and got it to 90 degrees in 50 minutes. I know that is on the low side, but that was body heat only and a short period of time. So, I am figuring I will try it out with the heating pad and time it at 1 hour and 2 hours and see where my temps are. that way, even if i go immediately i can sit back and drink water and drag things out until hopefully the temperature is right...

okay, so here are the results of my heating pad testing with no other heat source. I put the heating pad on at 5:02 and was going to go for a straight hour and then test temp but my husband wanted to go to happy hour and threw things off. So, I took the temp at 5:34 and it hadn't even hit 90 degrees, the heat pack was still cold. was wondering what was going on with the heat pack by this point. i decided to go out and leave the heat pack rubber banded to the QF and was gone around an hour. when i got home i checked the temp on the QF and found it to be 92.7. This was just with the heating pad attached and it sitting in a drawer. I took the QF and crotched it for 30 minutes and measured the temp and it was 97.9. I am sure if I had not removed it, it would have hit that temp sooner. My thoughts are that even w/o a microwave/hot water/etc. you may be able to reach the right temp within 2 hours. Obviously, I will practice this again. The hand warmers I used were heat factory brand and say they last ten hours? hope this helps and if anyone else has any suggestions for me, please let me know.