Summary for urine corrosion on aluminium Discussion
Urine corroded aluminium and steel toilet frame because the mixed metals were exposed to a hostile, salt-like environment and the area was left uncleaned for over a year. Mark Benyon asked whether the failure was a battery-type reaction or simple urine attack on the aluminium. Jeffrey Holmes replied that in any salt environment, aluminium connected to steel will corrode rapidly; he noted that aluminium is often used sacrificially to protect steel, so the aluminium tube would be the part to fail. He also advised that good design should avoid mixed metals in hostile environments and should not create hidden areas where spillage can accumulate. The thread suggests the corrosion was driven by galvanic action plus prolonged contamination, not urine alone.
We make a steel toilet frame which extends in width via an aluminium tube insert. Where the steel and aluminium are together a lot of urine splashes and we have a frame that has not been cleaned for over a year The aluminium has corroded and snapped. Is this a battery type reaction or will the aluminium tube be corroded anyway by the urine?
Mark Benyon
manager – UK
July 5, 2011
July 12, 2011
Hi Mark
Given any sort of salt environment aluminium connected to steel will corrode rapidly. Aluminium is used as a sacrificial anode on steel ships so your steel frame should be well protected!
Two points
It is good design practice to avoid mixed metals in a hostile environment; even to the extent of ensuring that any weld filler matches the structure.
And why has this toilet not been cleaned for a year? The design should not have hidden areas where “spillage” can accumulate.
Geoff Smith
Hampshire, England
Q. At work we have a lid on our lift station for our septic. We are making a new lid and it is made out of aluminum so my question is will urine eat the aluminum?
Travis Kieffer
– Litchfield, Illinois, USA
June 27, 2012
A. If urine attacks the aluminum, improve your aim.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
August 4, 2012