Lye bath and rust

GTurner

Member
I know it is said that you can keep a piece of CI in a lye bath for a very long time with any issues, but how is that possible since water is the worst thing for cast iron? Wouldn't the water which is 5 gallons per pound of lye cause some rusting?

If not, how does the lye protect from rusting?

I've pulled out a few pieces of late that I have left in for more than my usual time and there appears to be more rust on the pieces than I normally see. I know that these pieces might have had the rust under the crud that was removed.

I'm about to clean my tank and start new. This has me wondering if the concentration of lye has reduced possibly causing this.

Thank to all in advance.
 
From my little experience... I’ve noticed lye doesn’t do much for rust to begin with. I use Lye to get the crud off and it gets into the writing (if any) better to loosen that crud up too. If I notice rust after the lye bath... it will spend the night in my E Tank to remove rust and anything else.
 
Lye won't affect existing rust. Rust formation, however, requires a pH below about 8.2, which the lye tank, if at the typical strength, will far exceed.

Rust is soluble below a pH of 4.0, but iron is also corroded at that level of acidity.
 
Thank you Doug. The pH of the lye bath is greater than 8.2. I know that lye doesn't remove rust. My elbow grease does lol. My bath may have dropped below it. I just changed it out.

In an apartment without a balcony, so no e-tank. -sniff-
Lye won't affect existing rust. Rust formation, however, requires a pH below about 8.2, which the lye tank, if at the typical strength, will far exceed.

Rust is soluble below a pH of 4.0, but iron is also corroded at that level of acidity.
 
Will a tank with washing soda remove the rust?
I'm also new to this, but want to clean what I have.
Or am about to get.
Thanks.
 
Washing soda (sodium carbonate) is used in an electrolysis tank to create an electrolyte. Being alkaline, it's of no use on its own as a rust converter.
 
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