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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 |
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