As some of you may recall, I am in the process of setting up a permanent shop in my garage. One thing that I feel I need is an air compressor for general purpose use. I will probably run an air line down the middle (on the ceiling) and have several outlets, including one at the garage door for outside use on cars and bikes.

I plan to locate the compressor and tank in a small utility room in the rear corner of the garage which it will share with the water heater and my grinding equipment (to help keep the abrasive dust away from my other machines). So I will probably use extra filtration on the air intake or run an intake pipe throuth the wall to the garage itself.

Anyway, now for my questions.

First, I have an idea to purchase a somewhat small, portable compressor, probably with a small tank. My needs for air are not large and my bank account is somewhat small. Making it portable will allow it to be used in other locations. But, I may need larger quantities of air at times. So I am thinking about getting a larger tank and adding it to the system. It would be located downstream from the original tank and could either be filled at the same time or in increments with a solenoid valve and timer circuit. I am concerned with the run time of a smaller compressor and do not want to overheat it or otherwise exceed it's capacity and incur an early death.

I could use a timer circuit to limit the run time to some safe value and then let it rest for enough time to cool off before running again. It would take several such run-rest cycles to fill the big tank.

Or I could use a solenoid valve between the tanks and leave the original compressor's controls as is. The solenoid valve would open at intervals to allow the bit tank to fill from the smaller one. The time between these openings would assure the rest time for the compressor. It would only open for a few seconds to allow the pressures to equalize between the tanks. When the big tank reaches full pressure, it would stop operating.

Does anybody see any problems with either of these methods? Which would be better?

Second question would be about the pressure I should go for. I would think 60 or 75 PSI would be the minimum. Perhaps 100 or 150 would be better. Any thoughts here? I did say general use so I have no specifics here beyond the occasional tire inflation.

Third question would be on the sound level. I have installed air systems for commercial use and they were almost always loud. They were installed in an out of the way corner where the noise would be least likely to be heard. But this would be in my house, about 20 feet away from my neighbor's house - bedroom wing. So I don't want any complaints. Any advice on brands or types of compressors in this regard would be appreciated. Also, any suggestions on sound absorbing materials for the room. All I can think of so far is fiberglass insulation. That would also help with the AC bill in summer here in south Texas.