Impressed Current Anodes for washing machine drums – A way to extend lifespan? - Page 1
Forum section: electronics / general

author: BillyGo
author_rank: Contributor
timestamp: May 08, 2025, 02:57:34 am
content: About six hours ago, my 7 year old Siemens washing machine made a loud, explosive sound. I opened it up, unplugged the NTC sensor on the tub, and used an endoscope to inspect the inside. Apparently, the drum support, known as the 'spider' had disintegrated into pieces.After some Googling, I found that modern machines often use aluminium for the spider arm. When water is present, the stainless steel drum and aluminium spider effectively form a galvanic cell. Electrochemical reactions cause the aluminium (lower electrode potential ) to corrode over time, eventually failing.What are the possible options?Buy a Miele washing machine. Probably the best long-term solution, expensivePainting the spider or inserting nylon washers to isolate the metals, but these solutions aren't practical for machines with integrated tubs that are almost impossible to open.Add a sacrificial anode (like what's used in water heater tanks)—this is the first one I’m planning to try once I get a new washing machine. Stick a magnesium bar into the emergency drain area, fill the drum with soap and water, and then measure the potential difference between the magnesium and the drum. If it’s enough to create galvanic protection, I’ll try leaving the bar in place.But for me even more interesting is the idea of using impressed current anodes, like they do in modern water heater systems. This involves applying a low voltage between the tank and a titanium anode. The titanium doesn’t corrode, but by making it the anode via external current, it protects the rest of the system.In theory, maybe I could mount a mercury slip ring on the drum shaft and case and fix the slip ring to the drum via some soft material, like TPU? The drum could be biased as a cathode, and I can put the titanium bar somewhere others. I am not sure this would work in mechanically.

author: coppercone2
author_rank: Super Contributor
timestamp: May 08, 2025, 04:31:54 am
content: I heard something else that that is cast zinc aluminum alloy and it corrodes from soap. I noticed this before because I was storing soap water in a solder alcohol bottle and it was corroding it. Normal water is fine.I heard to use less soap and also turn on a extra rinse, just to get all the soap outa there .Undoubtedly its some cheap bullshit, but this sounds like some serious work to figure out with little guarantee.You did not notice if when you took it apart, there was alot of soap scum in there? Mine was like caked. But I always went heavy on the soap because I got a industrial quantity a long time ago for cheap

author: Halcyon
author_rank: Unknown
timestamp: May 08, 2025, 06:48:19 am
content: Interesting. I have a Siemens (Bosch) front-load washer which is approaching 11 years old. It has been perfect. Was the failure sudden or had you noticed some odd behaviour in the lead-up to it? Noises, vibration?I also leave both the drum door and detergent drawer open after every wash to dry out. I see no point in keeping moisture trapped in places where things can get manky, particularly around seals.

author: BillyGo
author_rank: Contributor
timestamp: May 09, 2025, 01:22:24 pm
content: Yeah, I actually don’t use powdered or liquid soap, mostly been using those laundry liquid capsules. But I did notice some sticky, gluey residue inside the plastic tub. Going forward.I’m planning to run empty cleaning cycles more often with baking soda. Hopefully, that helps for the next machine.

author: BillyGo
author_rank: Contributor
timestamp: May 09, 2025, 01:45:56 pm
content: It suddenly happens. I grew up using an ancient top load washer. This Siemens was a washer-dryer combo—so I guess I never really got into the habit of leaving the door open after washing.Interestingly, when I opened up the drying part after the failure, I noticed the heater wire still looked almost brand new. But the aluminium or zinc discharge scroll of the air duct was completely corroded, even had a few holes in the bottom. I never even noticed that because I started using a dedicated dryer in 2020.

author: nctnico
author_rank: Super Contributor
timestamp: May 09, 2025, 03:06:19 pm
content: Quote from: BillyGo on May 08, 2025, 02:57:34 amBuying a Miele is a good option. These are easy to fix so can last decades. Ours is over 25 years old already.However, Miele has or is using the aluminium spiders as well on newer machines which cause the same problem. I can probably sell our Miele for good money just for the steel spider so somebody can upgrade a machine.Every now and then I run a cleaning cycle using soda at the hottest setting. BTW, don't use baking soda or caustic soda, use the regular cleaning soda.