Electrical Problem

Hi guys. I've got a problem with a some lamps I wired for a vertical growing system. I am going to be running two 1000w lights on magnetic ballasts through a cool tube that I built. I've wired the sockets into lamp housings that I made out of some HVAC reducers, and attached the actual sockets to the housing with some Simpson strong tie aluminum straps via one wingnut per socket to be able to center it inside the housing. It is grounded to a nut and a washer that is inside. The problem is, when I turn the light on, it will stay on for a few minutes and them go out and glow orange, eventually burning up the bulb if not removed. I had the system running without the lamp housing, with the sockets attached to the frame of the system with just the strong ties and it worked fine. I let it run for a few hours to test it. I have a heat issue, so I need the cool tube, hence the alteration. Anyone know what this problem could be?

Things I've tried:
Changing to a different ballast.
Changing to a different plug circuit.
Taking the durn thing apart and putting it back together...ugghh...
I've even taken a plug socket apart and checked to see if the wire was big enough to carry the load and it appears to be.

Could it be that only one wing nut attaching it to the strong tie is allowing the lamp socket to vibrate slightly...? The lamps seemed sturdier when attached to the frame via the strong ties only...

I kinda dumb-founded and need the help of a real electrician...

As soon as I can figure out how to attach some photos here I will. I am working on that right now.

Thanks guys.