AC Manifold rebuild - poly 80, bronze or SS?

[formosa64]

Hi all,
I am going to rebuild my AC raw water intake manifold. The original bronze developed a leak and was replaced with PVC sch 40 with glued fittings which I don't trust. What I've read sch 80 threaded fittings would be the minimum. I am thinking avoiding plastic altogether and going back to bronze although someone mentioned stainless steel would be a better choice?

Thoughts?

Thanks -

[Briankinley2004]

Following. My boat has PVC glued which I dont like. Bronze is what I was thinking as well. The strainer is brass/bronze as well as thru hull so it should last but will cost alot more.

[GJH]

I got mine from Sam's. Went with bronze. Replaces all the hoses while I was at it. They still carry them, mine was a five port:
http://parts.samsmarine.com/PartSear...ItemNmbr=91788

[Pascal]

Looking at the picture this doesnt look like bronze, but brass. It looks very much like a manifold i had to replace a few years back because it was corroding.

If well supported sch80 is supposed to be ok although last week a new 65 Sunseeker almost sank on the way to bimini after a sch 80 air con fitting on the pump broke. Apparently the hoses or pipes where not properly supported

On my boat, i used nylon fittings to build the manifold. Soft enough to resist vibrations, easy to assemble and will never corrode. Also a lot cheaper than this premade manifold. You can also over size the fittings to pr vent shells from reducing flow. Being able to disassemble the manifold make it easier to clean when shells build. Ve had an issue with small mussel shapped shells in south florida which can clog manifolds and lines

[formosa64]

Good info, had not considered nylon. I looked up the tensile strength in the materials data book and it's > 2x of PVC. Fracture toughness is also higher than PVC although not significant. Nylon is at the upper range for thermoplastics for fracture toughness - only PET is higher.

[JohnEasley]

i used nylon fittings to build the manifold. Soft enough to resist vibrations, easy to assemble and will never corrode. Also a lot cheaper than this premade manifold.

I looked up the tensile strength in the materials data book and it's > 2x of PVC. Fracture toughness is also higher than PVC although not significant. Nylon is at the upper range for thermoplastics for fracture toughness - only PET is higher.

Anyone have an online source for nylon fittings to build a manifold?

[formosa64]

I'm seeing everything but a "cross" at West Marine. "Seafit" brand fittings.

[GJH]

Looking at the picture this doesnt look like bronze, but brass. It looks very much like a manifold i had to replace a few years back because it was corroding.

If well supported sch80 is supposed to be ok although last week a new 65 Sunseeker almost sank on the way to bimini after a sch 80 air con fitting on the pump broke. Apparently the hoses or pipes where not properly supported

On my boat, i used nylon fittings to build the manifold. Soft enough to resist vibrations, easy to assemble and will never corrode. Also a lot cheaper than this premade manifold. You can also over size the fittings to pr vent shells from reducing flow. Being able to disassemble the manifold make it easier to clean when shells build. Ve had an issue with small mussel shapped shells in south florida which can clog manifolds and lines

It looked like bronze to me as did the 30 year old one I replaced. But I could be wrong. I valued my time to fabricate one (sourcing the material and assembly labor) as being much more than 300 bucks. If you value your time at zero, well it is cash-out cheaper to glue one together out of nylon or whatever.

[Pascal]

You don't have to glue nylon or marelon You just get screw it all together it takes a few minutes and no worry about corrosion.

It's just a few female tees, some male male nipples, and female to barbs. Most decent chandlery will have the pieces

I ve seen too many boats with crumpling corroding brass manifolds to ever use one again

[Canuck Dennis]

Also, mixing threaded plastics with any threaded fittings other than plastic is a recipe for a failure.