Pete C. wrote:
The Daring Dufas wrote:
Stormin Mormon wrote:
Copper pipe comes in hardness grades. K, L, and M. K copper
(it's been years since I needed to know this) is soft, and
comes on rolls. L, and M are rigid and should not be bent if
possible.

Of course, the goal is to bend it as little as possible.

I have a tendency to use refrigeration grade soft copper for
everything because I can bend it and form my own fittings
with the tools I have. I rarely purchase couplings or elbows
since I can make my own.

TDD

K, L and M are wall thickness grades (like sch. 80, 40, 20) and have
nothing to do with hardness. Both soft copper and hard copper are
available in the different grades.

Refrigeration grade tubing is yet another thing, and mostly refers to
the fact that the tubing has been cleaned and capped to keep out
contamination that could damage refrigeration equipment with small
orifices, etc. Plumbing grade tubing isn't cleaned and capped since
water pipes can be readily flushed of impurities. Refrigeration grade
tubing is also specified by it's outside diameter vs. plumbing which is
specified by nominal ID.

I do more HVAC and refrigeration work than plumbing so the pipe I
have on hand is refrigeration tubing. In order to get me to do any
plumbing work, you have to point a gun at me or torture me by the
crinkling a stack of hundred dollar bills in front of me ploy.

TDD