I used Scd 80 PVC to construct a seawater manifold exactly as you describe
for Swee****er -- 2" top quality seacock and then hose and Scd 80 from
there.
----
However, first I should say that a Dogpile search on "bronze pipe" came up
with several suppliers such as
Farmer's Copper & Industrial Supply, Inc.
P.O. Box 2649
Galveston, TX 77553-2649
USA
Tel: 800-231-9450
Fax: 409-765-7115
Product Description
Inventories C65100 Silicon Bronze Pipe From 1/2"
To 6" Schedule 80 & C65500 Silicon Bronze
Welded Pipe To Specifications
Once you had Silicon Bronze pipe, making nipples is a PIA, but no sweat.
West claims that its Apollo ball valves have Stainless Handles and you could
always fab new handles for the Conbraco valves from 316.
And, of course, our favorite industrial supplier will be happy to sell you
either 304 or 316 fittings for a price. I would probably be OK with 316
(maybe even 304) for cold seawater.
Finally, there's galvanized steel. Fintry's piping maze (see
http://www.mvfintry.com/pix/piping800.png) is mostly galvanized steel. Most
of it is thirty years old and has passed a rigorous survey recently. Some
was replaced in her refit in 1998. The only thing about that makes it
difficult to duplicate is that it's all welded lengths, with four bolt
flanges at every valve and coupling (tees and wyes are welded). There are
no threaded connections. Steel fails softly and slowly -- you get a weep
and then, if you ignore it, six months later you have a problem. You'd want
Scd 80 here, not for strength, but for more material to rust before failure.
Scd 80 Issues:
1) the Scd 80 will burn. On a boat with a lot of seawater hose below the
waterline, this isn't an issue, because the hose will burn anyway (and so
will the hull, in a glass or wood boat) -- but on Fintry, all below w/l
seawater is in pipe so that if we have an engine room fire, we can (it says
in the manual) shut off the air vents, pop the foam, and wait for it to go
out, without worrying about sinking the boat. ("all" isn't quite true --
there are some on-engine hoses, but I hope those will boil for a while
before burning through)
2) Scd 80 is more fragile than metal valves with hose. On Swee****er, the
manifold was stuffed between two floors and thoroughly protected. I'm
pretty sure you could jump on a Scd 80 manifold without damage, but its
protection would need care.
3) there are a few fittings that are very hard to source in Scd 80 (I don't
remember what, but only that there was one white piece -- a barbed nipple I
think).
4) There are surveyors who will hate it. We had Swee****er surveyed by a
tough old guy (gone now) just before the trip (insurance company insisted,
but it's a good idea to have an independent check on your work) and he was
happy with it (I had checked with him before we did it). If you are
insuring, then figure out who will do the survey after launch, and ask him
or her.
5) On the other hand, a lot of big boats use Scd 40 pvc for internal
piping -- not seawater, but things like sewage, and surveyors are OK with
that (stinking is OK, sinking is not?).
6) A lot of the bits and pieces we put on Swee****er had Scd 40 PVC --
fittings for air con, watermaker, refrigeration seawater -- all "good"
brands.
Jim Woodward
www.mvFintry.com
"Glenn Ashmore" wrote in message
news:6tRpb.999$62.845@lakeread04...
I am building a manifold to feed the washdown pump, air conditioning
cooling pump and watermaker bost pump. The supply is a 1 1/2" hose
coming from a 1 1/2" bronze seacock and Groco 970-1515 strainer. Engine
cooling water is supplied through a 1" hose that comes off a 2"x1.5"x1"
Groco manifold at the strainer
I would use bronze reducing tees except that nobody makes bronze pipe
nipple. Only steel, brass or stainless. All three of which are not
acceptable. So I have decided to fabricate it from a length of 1" wall
PVC tube with 1/2" threaded schedule 80 stubs for the valves.
Now comes the question of the valves themselves. I have some Conbraco
bronze ball valves that would work but my experience with them in the
past has not been all good. While the valve body is bronze the handle
is mild steel. On several deliveries of older boats the handles have
rusted to the point of being unusable and I have had to resort to Vice
Grips to operate the valve.
OTOH, I also have some Schedule 80 all PVC ball valves with stainless
handle retaining screws. I know that ABYC frowns on using PVC on
throughhulls but if the throughhull has a bronze seacock what are the
rules for down stream valves?
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com