In addition to the comments on crevice corrosion of stainless, especially with salt water, I would like to add the following concern: I know from my homebrewing experience that household bleach is VERY corrosive to stainless steel. Now, the active ingredient in household bleach is sodium hypochlorite, which may be somewhat different from the chlorine they use in swimming pools, but I've always wondered if those who practice rolling during the winter months in swimming pools should be concerned about any stainless parts on their kayaks. Perhaps those on this list with more knowledge of these matters could comment? *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
This is your friendly water chemist back (who'd actually much prefer to earn a living while kayaking). The sodium hypochlorite in bleach, is the same material that is used in treating swimming pools and potable water. Sometimes you will also see calcium hypochlorite being used. The "active" part of the compound is the hypochlorite ion which forms hypochlorous acid when dissolved in water. This is the material that is a very strong oxidizing agent and kills all the little unwanted critters in the water. As the hypochlorous acid is consumed, you will be left with chloride ions (the same little buggers that are found in table salt or salt water). Chlorides are very corrosive to stainless steel and causes it to become brittle and to crack across the grain boundaries. The amount of chlorine used in a swimming pool is very small, on the order of 1 - 3 milligrams per liter (mg/l) or about 1 - 3 lbs per 120,000 gallons of water. This should not be a problem with our boats. I've had my boat in my pool several times and I've noticed nothing with the stainless steel skeg cable. I'm more worried about the gel coat on the sides of the pool. Steve Holtzman ----- Original Message ----- From: Randy Ricchi I know from my homebrewing experience that household bleach is VERY corrosive to stainless steel. Now, the active ingredient in household bleach is sodium hypochlorite, which may be somewhat different from the chlorine they use in swimming pools, but I've always wondered if those who practice rolling during the winter months in swimming pools should be concerned about any stainless parts on their kayaks. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Randy Ricchi <rricchi_at_houghton.k12.mi.us> wrote: >>I know from my homebrewing experience that household bleach is VERY corrosive to stainless steel. Now, the active ingredient in household bleach is sodium hypochlorite, which may be somewhat different from the chlorine they use in swimming pools, but I've always wondered if those who practice rolling during the winter months in swimming pools should be concerned about any stainless parts on their kayaks. Perhaps those on this list with more knowledge of these matters could comment?>> The concentration of chlorine in pool water is very low, somewhat higher than that in tap water, so the damage to your SS fittings is likely to be small, especially if you rinse well. Even so, you should pull some of the deck hardware and check now and then. In addition, if your kayak has SS cables for rudder control, I'd replace them every second year or so. (Note: I do not follow my own advice: I have copper-sleeved SS cables in my Wind Dancer that have been in service since 1997; they are a second set. The first set lasted from 1993 to 1997. A buddy replaced his SS cables when they cratered (not at the sleeves, but inside the yak, some 5-6 inches from the rear entry) in 1998 after 12 years of service. Replacing cables every two-three years is very safe, IMHO, but I do carry a spare.) Others have emphasized the need to minimize the contact of dissimilar metals, but as Steve Scherrer points out, copper sleeves on SS cable and wire have been a marine industry standard for years, and hold up well in service. The green sheen that builds up at the sleeve/cable contact is evidence for slight corrosion of _the copper_, and not the SS, which (perversely) might be __protected__ from crevice corrosion by this practice. This may seem counter to the normal advice of placing a "more active" sacrificial metal in contact with the metal you want to preserve. But, remember that to remain protected, the SS has to maintain an __oxide__ coating on its surface (actually on the chromium and other alloying metals), so it has to remain as anode. Adjacent copper, which is less active than iron, may ensure this. I honestly do not know what happens inside a copper sleeve over SS cable, and have never seen any cross-sections of that arrangement after several years of service. Anybody got a picture of what one looks like? I'm guessing the "usual" guess re: dissimilar metals may not be the best practice for sleeves on SS cable, though I do agree aluminum is a really terrible choice for sleeving unless massive (which I think I may have seen on some large diameter wire rope on draggers around here). This sleeve business is a mystery to me, but most agree metallurgy is one of the technical disciplines where good theory sucks, and practical experience rules. -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
This archive was generated by hypermail 2.4.0 : Thu Aug 21 2025 - 16:33:31 PDT