A/C Hoses

[oldawg]

Replacement of the forward A/C system is moving apace. The new unit has been ordered from Aqua Air. A "while you're at it" includes building and new distribution manifold and associated hoses. Any recommendations on replacement hoses would be appreciated. System will be plumbed for easy system cleaning/flushing.

Thanks

 

[Pascal]

I used regular pressure resistant hose, clear with webbing reinforcement

Make sure you don't use brass for the manifold!

 

[captddis]

The black non wire hd water hose works best. Barnacles love the white and clear hose. As Pascal said NO brass NIPPLES in the AC manifolds or plumbing.

 

[Mambeaux]

OK, I have to ask. Why no Brass??

 

[Boatsb]

OK, I have to ask. Why no Brass??

Because its not good with electrolysis or acids..

 

[Angela]

OK, I have to ask. Why no Brass??

My experience with "red brass", which is better than ordinary yellow brass, as I understand the make up of the metal, is that salt water eats that for lunch. I had a fitting that my marine store labeled as bronze, but was actually red brass. Less then three months later, and I walked back in there with the swiss cheese fitting, they sold as "bronze", explaining how that could have sunk my boat.

 

[Pascal]

Brass fittings will last from 6 months to 3 years when used in air con sea water lines because of galvanic corrosion

It you are lucky they will fail when you touch them and not while you re away from the boat.

 

[captddis]

It is errosion not galvanic corrosion.

 

[bobk]

It's not errosion. The copper remains, the zinc portion of the alloy "dissolves". I've never researched it, but suspect it is mostly the galvanic action.

If you ever see bluish deposits on what may be brass, it has become porous and brittle. R&R ASAP.

Bobk

 

[captddis]

It's not errosion. The copper remains, the zinc portion of the alloy "dissolves". I've never researched it, but suspect it is mostly the galvanic action.

If you ever see bluish deposits on what may be brass, it has become porous and brittle. R&R ASAP.

Bobk

Maybe do some research first!!! The nipples only fail on the discharge side of the AC system. The same nipple that is between the thru hull and strainer almost never fails. It is the cavitation bubbles and water pressure AFTER the pump.

 

[bobk]

Maybe do some research first!!! The nipples only fail on the discharge side of the AC system. The same nipple that is between the thru hull and strainer almost never fails. It is the cavitation bubbles and water pressure AFTER the pump.

Lets be friendly here..... true HOFers that we are. I didn't mean to strike a nerve and if I did, please accept my apologies.

When I said I never researched the issue, I meant as a study during my 42 years as a research chemist. That was all related to plastics, rubber, plumbing and high tech composites (think aircraft). That said, I have experienced porous and brittle brass fittings on both sides of raw water filters before the pump, and also had a brass elbow fail on the inlet to a stuffing box. I'm sure these were not errosion or cavitation related. This process is commonoly called dezincification - that is when the zinc component of brass dissloves out or leaches from the brass. There are several mechanisms for this and it occurs in city tap water as well as in salt water. Galvanic corrosion is one of those mechanisms. A quick Google search for dezincification or corrosion of brass will lead to lots of information and pictures including a few published research papers.

Bobk

 

[GJH]

Bob, if the strainer/through hull and pump head are both bonded to the bonding system, could you explain why would galvanic corrosion take place? You certainly see a lot of brass sold in marine supply stores, and nipples in particular are almost impossible to find in bronze.

 

[Boatsb]

It's not errosion. The copper remains, the zinc portion of the alloy "dissolves". I've never researched it, but suspect it is mostly the galvanic action.

If you ever see bluish deposits on what may be brass, it has become porous and brittle. R&R ASAP.

Bobk

Bob, if the strainer/through hull and pump head are both bonded to the bonding system, could you explain why would galvanic corrosion take place? You certainly see a lot of brass sold in marine supply stores, and nipples in particular are almost impossible to find in bronze.

George nipples are very available in bronze. We buy all kinds of through hull hardware, hose barbs and adapters for projects on a weekly basis. In the last month I probably installed a dozen seacocks and even put bronze caps in the ones not imediatelt plumbed in.

 

[captddis]

Lets be friendly here..... true HOFers that we are. I didn't mean to strike a nerve and if I did, please accept my apologies.

When I said I never researched the issue, I meant as a study during my 42 years as a research chemist. That was all related to plastics, rubber, plumbing and high tech composites (think aircraft). That said, I have experienced porous and brittle brass fittings on both sides of raw water filters before the pump, and also had a brass elbow fail on the inlet to a stuffing box. I'm sure these were not errosion or cavitation related. This process is commonoly called dezincification - that is when the zinc component of brass dissloves out or leaches from the brass. There are several mechanisms for this and it occurs in city tap water as well as in salt water. Galvanic corrosion is one of those mechanisms. A quick Google search for dezincification or corrosion of brass will lead to lots of information and pictures including a few published research papers.

Bobk

No need to apoligize and I am sorry if I got to snippy. Your galvanic / dezincification is accurate, but in AC systems the pipe nipples die from errosion/cavitation 90% of the time. The point I tried to make is never use nipples in the AC discharge plumbing. Use either cast bronze or schedule 80 PVC. Dave

 

[GJH]

George nipples are very available in bronze. We buy all kinds of through hull hardware, hose barbs and adapters for projects on a weekly basis. In the last month I probably installed a dozen seacocks and even put bronze caps in the ones not imediatelt plumbed in.

Where did you get bronze nipples? That seems to be the one hard to find bronze item. Not even Buck Algonquin makes them.

Edit OK, I see Groco makes some. Damn hard to find at retail, even in Ft Lauderdale last i looked... impossible here in eastern NC and we have some good marine hardware stores.

 

[Boatsb]

Where did you get bronze nipples? That seems to be the one hard to find bronze item. Not even Buck Algonquin makes them.

Edit OK, I see Groco makes some. Damn hard to find at retail, even in Ft Lauderdale last i looked... impossible here in eastern NC and we have some good marine hardware stores.

Lewis marine has a good supply here locally and the have a ft liquordale and a nd location although wholesale. I believe they supply many of the local marina stores here so I bet you could have them ordered.

 

[captddis]

Where are the bronze nipples in the Lewis book? The only ones I see are brass. Most sell red brass and call them bronze. Could you give the figure number?

 

[Boatsb]

Where are the bronze nipples in the Lewis book? The only ones I see are brass. Most sell red brass and call them bronze. Could you give the figure number?

2012 catalog. Page 588.

 

[captddis]

My Glen Mar book does not show it.

 

[Boatsb]

You need a Lewis catalog?