On Mar 24, 1:01*pm, wrote:
On Mar 24, 2:02*am, Bob Hoover wrote:

On Mar 23, 8:14*am, wrote:

Without seeing it I would have guessed a contaminant on your filler
rod, but if it's happening ahead of the pool it may be something on
the tubing, such as some sort of residue from the zinc.

-Bob

I'm leaning toward that myself. When the tubes came out of the acid, I
rinsed them in clean tap water and then let them air-dry. I actually
watched them rust in a period of 5 minutes. Once the tubes were dry, I
shoe-shined them with a Scotchbrite pad. They looked nice and shiny,
but I didn't do any further cleaning. I also didn't clean the filler
rod. Its copper-coated, but that doesn't seem to be doing it, or I
would have the problem all of the time.
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Okay. At least we are singing off the same sheet of music. And to be
honest, the stuff we used, circa 1972, was salvaged from a local
lumber yard in a building erected sometime between 1945 and 1953.
They gave us (the local Scout troop) the stuff in return for hauling
it away. The EMT had held only a couple of wires, which we salvaged
and sold as copper scrap. The EMT was sliced into 12" lengths BY HAND
using Boy-Power (a Troop joke), and hack-saws having 32 tpi.

After chopping we had a fair sized BIN of tubing 'coupons' on which to
practice, plus a pretty good pile of long pieces destined for another
Project... once the boy's learned to weld tubing.

To remove the galvanizing we cheated a bit and hauled most of the
stuff to a shop in Oceanside where the guy dipped them in heaven knows
what but it required neutralizing. On the final dip the coupons
picked up a film of oil that was floated on the Mystery Fluid (which I
thin was just hot water). Bottom Line: No rusty coupons even a year
later... although we did have to de-grease the stuff before using.

One of us was a Navy Chief, several other fathers were Marine Corps
NCO's. Another was a dentist, another the Shop Teacher at our local
high school. I mention all this because nowadays, in so far as I
know, we don't even have a Scout troop; the local school district has
86'd ALL 'shop' classes due to various Fears and Budget Problems...
most of which are the Product of the same local School District
members. Our little town (Vista, California) is now a fearful place
where Political Correctness carries more weight than having a roof
that don't leak, a car that runs good, and if you want to get anything
DONE you'd damn well better be able to speak Spanish because the local
crop of youngsters willing and ABLE to tackle life's physical chores
has vanished into the reality of computer games... played on machines
they can't repair... and discussed via hunt & pecked messages because
they can't touch-type.

-Bob (who is still coming up with those Dreadful Projects... [the
current acorn is how to build a cabinet that turns an inexpensive
portable electric saw into an even less expensive Table Saw, needed to
reduce scrap lumber to longerons and sticks for ribs and a hell of a
lot of fun along the way.)

But I fed you a clanger on the tubing, Harry. But I was afraid if I
dug too deeply into the Nitty and the Gritty I'd soon find myself with
no one to talk to :-)