At 07:04 PM 8/17/03 +0100, you wrote:
>Royce reported that the top and bottom plates of his T boiler bulged.
This is
>perfectly normal - just bash them back into shape and re-test.
>Mike (been there, done that - just like Harry?)
Umm . . . no, not yet, but I expect I'll see any number of curious things
should I live long enough. Admittedly I build my ga1 boilers with a bit
thicker material than is typical, 16ga heads and Type K (18ga) tubes, and
only test to 2X, so bulging even at an over-pressure should be minimal to
invisible.
I've never mentioned it because it simply wasn't relevant but I did once
do a hydro-test on an arch-typical Ga1 boiler, (ie, 2" od x 7", center flue
with 16ga heads) and I took it to nearly 200 psi at which point the check
valves on my pump failed to hold a seal, but no matter I'd seen what I
needed to see. I had set up a DTI on the backhead to measure deflection
and deformation and IIRC total deflection at near 200psi was on the order
of .015" and deformation, the permanent change in the material, was about
.005".
Regards,
Harry
