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Plastic seacocks?

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Created by Seebreasy73 > 9 months ago, 1 Nov 2018
Seebreasy73
QLD, 334 posts
1 Nov 2018 7:35AM
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I was browsing Bunnings the other day and seen some plastic seacocks. I have one or two seacocks soon needing replacement and I was wondering if anyone has any experience with these instead of bronze or stainless? I could not think of a reason, why wouldn't these work on a boat.

twodogs1969
NSW, 1000 posts
1 Nov 2018 9:00AM
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I would only use plastic above the water line.

mottle33
NSW, 14 posts
1 Nov 2018 9:10AM
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I believe that the plastic used in Tru-design type seacocks is suitable for purpose, anything cheaper might be ok or not. The tru-design ones work very smoothly and are a joy to use. It is good insurance to get the right gear in critical areas such as below waterline security.

dralyagmas
SA, 380 posts
1 Nov 2018 9:41AM
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I installed Tru Design and they are great.

DO NOT use seacocks bought at Bunnings. The Tru Design are a specific hardened plastic designed for below water applications in boats. Bunnings are designed for irrigation systems.

Hence the Tru Design are more expensive

Wander66
QLD, 294 posts
1 Nov 2018 10:31AM
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Select to expand quote
Seebreasy73 said..
I was browsing Bunnings the other day and seen some plastic seacocks. I have one or two seacocks soon needing replacement and I was wondering if anyone has any experience with these instead of bronze or stainless? I could not think of a reason, why wouldn't these work on a boat.


Don't use the irrigation valves as seacocks. Even my slightly saline bore water kills them after a couple of years, it would be much worse in salt water.

wongaga
VIC, 664 posts
1 Nov 2018 1:12PM
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I recall reading positive things in PBO about "Marelon" seacocks. Might be worth doing a search for them.

Cheers, Graeme

Ramona
NSW, 7757 posts
1 Nov 2018 6:02PM
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wongaga said..
I recall reading positive things in PBO about "Marelon" seacocks. Might be worth doing a search for them.

Cheers, Graeme


Marelon is the trademark name for the reinforced plastic used in Tru design and other seacock manufacturers. I have only one plastic skin fitting, intake for the heads. I suspect it will have to be changed out eventually, I have penciled it in for 49 years time.

Kankama
NSW, 827 posts
1 Nov 2018 8:59PM
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Wander66 said..

Seebreasy73 said..
I was browsing Bunnings the other day and seen some plastic seacocks. I have one or two seacocks soon needing replacement and I was wondering if anyone has any experience with these instead of bronze or stainless? I could not think of a reason, why wouldn't these work on a boat.



Don't use the irrigation valves as seacocks. Even my slightly saline bore water kills them after a couple of years, it would be much worse in salt water.


Is this the point where I say I have used them for about 18 years? Toilet inlet and outlet, no degradation, all fine. Nice and epoxiable. Toilet outlet just above the waterline but the inlet is about 200mm down. A bit hard to turn but no change in all the time I have owned my boat.

Seebreasy73
QLD, 334 posts
1 Nov 2018 8:36PM
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Select to expand quote
Kankama said..

Wander66 said..


Seebreasy73 said..
I was browsing Bunnings the other day and seen some plastic seacocks. I have one or two seacocks soon needing replacement and I was wondering if anyone has any experience with these instead of bronze or stainless? I could not think of a reason, why wouldn't these work on a boat.




Don't use the irrigation valves as seacocks. Even my slightly saline bore water kills them after a couple of years, it would be much worse in salt water.



Is this the point where I say I have used them for about 18 years? Toilet inlet and outlet, no degradation, all fine. Nice and epoxiable. Toilet outlet just above the waterline but the inlet is about 200mm down. A bit hard to turn but no change in all the time I have owned my boat.


are you referring to the Bunning ones?

Seebreasy73
QLD, 334 posts
1 Nov 2018 8:47PM
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just found this:

Applications
PVC valves are used intensively in water management and irrigation. PVC is also suitable for corrosive media, such as sea water. Moreover, the material is resistant to most acids and bases, salt solutions and organic solvents. In applications where corrosive chemicals and acids are used, PVC is therefore often chosen above stainless steel. PVC has also some disadvantages. The most important drawback is that regular PVC cannot be used for media temperatures above 60?C (140?F). PVC is not resistant to aromatic and chlorinated hydrocarbons. PVC has a lower mechanical strength than brass or stainless steel, and therefore PVC valves have often a lower pressure rating (PN16 is normal for valves up to DN50). A list of typical markets where PVC valves are used:
Domestic / Professional Irrigation
Water treatment
Water features and fountains
Aquariums
Landfills
Swimming pools
Chemical processing
Food processing

So I guess it should be ok to use on the cold water side even a Bunnings one. I would still leave the original thru hull bronze fitting in place, just use the plastic valves on top.

Jolene
WA, 1624 posts
1 Nov 2018 7:17PM
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Use them on my boat too

Kankama
NSW, 827 posts
2 Nov 2018 5:39AM
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Yes the Bunnings ones. I actually like the idea of PVC because I epoxied the holding tank tap into the bulkhead. PVC loves epoxy whereas the nylon valves don't. So it works well for me.

Wander66
QLD, 294 posts
2 Nov 2018 6:48AM
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Kankama said..

Wander66 said..


Seebreasy73 said..
I was browsing Bunnings the other day and seen some plastic seacocks. I have one or two seacocks soon needing replacement and I was wondering if anyone has any experience with these instead of bronze or stainless? I could not think of a reason, why wouldn't these work on a boat.




Don't use the irrigation valves as seacocks. Even my slightly saline bore water kills them after a couple of years, it would be much worse in salt water.



Is this the point where I say I have used them for about 18 years? Toilet inlet and outlet, no degradation, all fine. Nice and epoxiable. Toilet outlet just above the waterline but the inlet is about 200mm down. A bit hard to turn but no change in all the time I have owned my boat.


I just find they start to leak after a while when under pressure all the time, but in a boat where there is little or no pressure they might be fine. Still would trust them to keep the ocean out though.

woko
NSW, 1802 posts
2 Nov 2018 8:17AM
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Had some pvc cocks on ag spray rig they handled the chemical but the handles mostly broke. On my boat I would be happy with pvc ( from a plumbing supplier) above the waterline, fresh water tank etc but below the waterline I'm inclined to use the trudesign rated seacocks quality hose and clamps, the price difference is cheap insurance.
ps. If you change out your bronze skin fitting as well there's one less cause of electrolyses

Seebreasy73
QLD, 334 posts
3 Nov 2018 9:18PM
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woko said..
Had some pvc cocks on ag spray rig they handled the chemical but the handles mostly broke. On my boat I would be happy with pvc ( from a plumbing supplier) above the waterline, fresh water tank etc but below the waterline I'm inclined to use the trudesign rated seacocks quality hose and clamps, the price difference is cheap insurance.
ps. If you change out your bronze skin fitting as well there's one less cause of electrolyses


would love to change the sin fittings out as well, but I don't have the extra $400 to put the boat on a hard stand now even if I probably sould.
I went to Whittworths today and they the exact same seacocks what I seen at Bunnings.



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"Plastic seacocks?" started by Seebreasy73