"Andy Asberry" wrote in message
...
| On Thu, 25 Aug 2005 20:24:29 -0700, DaveC wrote:
|
| 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?
|
| Thanks,
|
| It is nowhere near 1/4" thick. Probably less than 1/8". I don't
| recommend welding on it. But if you're going to anyway, why not just
| weld on a coupling that is already threaded?

If the coupling stuck up inside the tank, there'd be a puddle that the
drain could not get to. I wonder how well a flange would work brazed to the
tank. Drill the hole, shape the flange to match very closely, then braze in
place. The low heat of brazing will not affect the heat treatment of the
tank wall that much. The flange ought not to be small, though. Weld a
coupling to the flange before brazing and connect that to the drain valve.

Does this sound safe?