"DaveC" wrote in message
news.net...
I've got an old 20 gal (?) compressor tank in which I want to install a
drain. I'm guessing it to be 1/4-inch (6.3 mm?) thick steel. Tank is rated
to
125 psi.

Can I drill and tap this for 1/4 or 3/8-inch pipe? Or should i get a
"plug"
welded to it that I can drill & tap?

Are there rules to follow for such stuff? Is there a better n.g. to ask
this
question in?


I got a great find last year in a nice two-stage pump that only needed the
valves re-seated to make it cherry again. I was also given a beautiful,
hot-dip galvanized upright propane tank of 100gal capacity. Hmmmm..... I
think I see a picture here.

I didn't want to compromise the tank's integrity because I'm NOT a good
weldor. So, I looked at things from a Rube Goldberg point of view.

Here we fill port, output port, and gauge port. The fill and output were
both 1" NPT bosses in good shape. The gauge port was a huge 2-1/4" machined
flange with the gauge bolted down onto a gasket.

Ok... fill will be fill; just screw in a check valve. Output was output;
natch. Took off the gauge and extracted the float assembly. Machined a
manifold that sat where the gauge used to.

In the manifold is a: Pressure relief port (tested... it does keep ahead of
the pump), a pressure gauge port, and... and... a dip-tube drain. It's just
a copper pipe that kisses the bottom of the tank, and a petcock valve to
open it to ambient pressure. Air pressure pushes the water up the tube.

I welded the pump base to the top flange and the feet to the bottom
flange -- never once touched a torch to the tank itself.

Since I'm not a weldor, I feel safer, and I've got a perfectly servicable
upright that has a drain valve I can actually reach without aggravating my
knees.

LLoyd