I need to order spare strainers. Which is the better way to go? Stainless Steel or Plastic?
I put a plastic one in my 2" Groco strainer and have been very happy with it. They are recommended for high use time applications such as raw water for air conditioning. The one I removed had lost it's bottom through electrolysis. The alternative is SS and attaching a zinc to it for a sacrificial element.
Ted
I put a plastic one in my 2" Groco strainer and have been very happy with it. They are recommended for high use time applications such as raw water for air conditioning. The one I removed had lost it's bottom through electrolysis. The alternative is SS and attaching a zinc to it for a sacrificial element.
Ted
If your seacock was a Groco, it was silicon bronze. If your basket was 304/316 stainless then electrolytic corrosion was not part of the problem.
Electrolysis had nothing to do with it.
Would not the bonding of the strainer eliminate the need for a zinc on the basket? I've had stainless baskets for years and never had any issues in salt or fresh water. I do twist them once in to insure they are seated. Maybe I'm making better electrical contact that way.
Must have been the stainless steel eating worms. What does the seacock have to do with it? The seacock wasn't bonded to the strainer; a rubber hose separated the two of them. BTW, the seacock was plastic. When I replaced the seacock and redid the plumbing, I installed a bronze seacock and tied both to the ships bonding system. Groco recommends the plastic strainer for applications such as AC where the pump has a high duty cycle. What to you think ate through the stainless if it wasn't electrolysis?
Ted
Electrolysis - A chemical change in an electrolyte due to the passage of current.
i.e. Electrolysis is what happens to the electrolyte, not the metals.
You may mean electrolytic corrosion or galvanic corrosion but again, "electrolysis" is irrelevant.
You may have simply had shitty Chinese "stainless" but silicon bronze and the stainless usually used in marine applications (304/316) are close enough on the galvanic (or Noble) scale to silicon bronze that any electrolytic activity would be extremely small and with virtually no measurable corrosion for many decades.
In your opinion...... how would you prevent it's reoccurrance?
Ted
No grammar involved. I believe correct terminology makes it easier for everyone involved. I often tell clients that if a "marine" electrician uses the term "electrolysis" they should hire someone else because they clearly do not understand electricity or corrosion.
When an "expert" uses the term "electrolysis" I know that marine corrosion is not their field of expertise. In my tenure with ABYC I helped develop the ABYC Marine Technician Corrosion course. In boats, the corrosion we most often deal with is galvanic corrosion. An application of sacrificial anodes is usually involved. We sometimes see stray current corrosion, but not very often. With stainless steel in salt water we sometimes see crevice corrosion. Adding anodes will not make any difference if crevice corrosion is the issue. As one who has SS sea strainer baskets, I see the corrosion start at the welds. This is a good indication that the issue is indeed crevice corrosion. Our boat was built in China in 2008 and some of the sea strainers are US products and some are Chinese. I have fewer problems with the baskets from Buck Algonquin, and can order replacements. I cannot seem to find replacement baskets for the Chinese knock off sea strainers.
We will be replacing our original raw water strainers with these marelon units from Forespar:
https://youtu.be/00xpK1C9ktY
We will be replacing our original raw water strainers with these marelon units from Forespar:
https://youtu.be/00xpK1C9ktY
Never use a plastic strainer basket! They last way too long and I can't get rich selling replacement baskets! Seriously, the plastic does seem to last longer. The holes are usually a little bigger but I've never heard of anyone having a problem because of that.
Pgitug, I was on your side of the world last weekend. Had dinner at the Torch restaurant. Outstanding food!