BTW I clear my pool lines using my shop vac. That really pushes quite a
bit through. I realize that my 1.5 inch lines don't compare to a 1" line.
But you might consider it. make an adapter using pvc and a step down.
It might be the ticket.

On 10/24/2011 11:51 AM, blueman wrote:
Ed writes:

On Sun, 23 Oct 2011 20:48:18 -0400, wrote:

I have a low-end Harbor Freight 8 gallon air compressor that has many
times over earned its $100 cost.

However, there are times when I would like to have a larger air supply
tank such as when I am blowing out my irrigation system. Of course the
steady-state is limited by the compressor motor to about 4-5 CFM@90 psi.

But I was wondering whether I could extend at least the initial volume
by adding an additional tank.


There are numerous ways to pipe the tank in line. Your reasoning is
correct, you get the initial burst, but that is all.

I'd pipe it in, but I'd put a valve in the line to shut it off. Two
reasons for that. There is no good reason to fill that tank if you
are not going to need the backup of air. Saves both time and energy
at startup for normal work.

Second, you can fill it, close the valve, and have it ready for use.
You can also open the valve and use that air if you only need a little
shot of it and not have to start the compressor.

All good points -- I actually am planning on doing that for all the
reasons you mention...