Hydrochloric Acid and Stainless Steel

[Twisted Brick]

Your basic toilet bowl cleaner will quickly dissolve minerals from stainless, but may require a little bit of scrubbing. Afterwards a thorough cleaning would be wise. Some of those thicker, gel toilet bowl cleaners that smell like bleach can be more mildly acidic and take longer to work.

This message was posted earlier and for safety reasons I feel it needs to be corrected. Not for the potential personal health hazards inherent in working with hydrochloric acid but because of the severe damage hydrochloric acid causes to stainless steel. From mash vessels to (conical) fermenters, boilers and storage vessels, the use of stainless is pervasive throughout our hobby.

From brief reading on the effects of hydrochloric acid on stainless steel, even a short contact period can cause irreversible damage including cracking, corrosion and pitting. Worse, it is also reported that the chemical reaction hydrochloric acid causes on contact with stainless steel compromises its ability to be later welded.

Metals such as aluminum, cast iron, steel, copper, and titanium will suffer rapid attack from HCl at all concentrations and temperatures. Most stainless steel grades will be subject to attack, because their chromium content is not sufficient in forming a protective passive layer.

A look into popular household toilet bowl cleaners revealed that virtually all use hydrochloric acid, and a random look found that one of the leading products, Lysol Brand contains 10-30% hydrochloric acid. From the above, it should be interpreted to avoid using toilet bowl cleaners on your ss vessels.

Lysol MSDS

Lysol Product Sheet

Hydrochloric Acid on Stainless Steel

If any member can report that these warnings and MSDS are inaccurate, please share what you know.

[8Ball]

+1 Good on you, Twisted, for advocating appropriate safety chemical safety protocol.

[Yummyrum]

I’ll agree with that . We had stainless Lab benches with pin holes right through them after kids would pour it down the sink . Even though the cleaners come every day and washed them out .And dishwashers destroyed because of HCl dripping on them out of test tubes waiting in the rack for a wash. Doesn’t even have to be strong . Even 1mol/l ( 10% strength) was enough to damage them . You’d wipe and wash and think you had them clean but once it started a pit , it just kept going .

[MooseMan]

Well pointed out Twisted Brick, and appropriate timing as it was mentioned in a thread I just commented on!
Incidentally, bricklayers used to use it in a weak solution to clean up at the end of a day!

HCL is the devil when it comes to metals. Even just the fumes will rust everything for many metres around it.

One thing to point out to anyone who is willing to risk using it on or near their stills, it melts solder, and I mean it actually dissolves it, quickly.

Hobby gold refiners use HCL to loosen gold contacts from PCBs, amongst other things. It's also the main component of Aqua Regia, which will pretty much dissolve any metal on earth.

[Twisted Brick]

HCL is the devil when it comes to metals. Even just the fumes will rust everything for many metres around it.

One thing to point out to anyone who is willing to risk using it on or near their stills, it melts solder, and I mean it actually dissolves it, quickly.

Yummy's lab accounts were an eye opener, but this is downright scary and good to know. Thanks for sharing.

[elbono]

While some may find the fast reaction times worth dealing with hydrochloric acid it isn't something for the casual user to consider.

In the US many toilet cleaners use hydrochloric acid. "The Works" is one that jogs my memory. We used to put strips of aluminum foil in a 1 liter soda bottle, add the works, screw the top on, shake it up and run. If you got the mix right the bottle would stretch to 3x it's height before it blew.

Aluminum is on the extreme side but HCl + any metal = heat + hydrogen + chlorine + oxidized metal.

Muriatic acid is another name for hydrochloric when used for cleaning brick, mortar etc.

If you use it be careful and don't use it on anything valuable.