Why has urine corroded an aluminium and steel toilet frame?

July 5, 2011

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

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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

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June 27, 2012

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

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