Hardware Chemicals #1: Hydrochloric Acid

Hydrochloric acid is an extremely useful and versatile chemical that has many uses around the home.

Its usefulness comes from the fact that it is a very strong mineral acid that is nonetheless generally safe to have around. This is because its bark is worse than its bite. In its concentrated form you’ll see white fumes coming off it, and if you catch a whiff of it it’ll hit you in the nose like a sledgehammer. This property alone is a strong deterrent for children and pets.But these fumes are only an irritant – they are not toxic.

If you get it on your skin it’ll sting, but it won’t burn (like sulfuric acid). And if you got it in your eyes, they’d probably survive, although it’d sting like hell. But you should be wearing safety glasses and gloves when handling it anyway.

And it’s cheap. A 20L drum from the hardware store will only set you back about $45. And because it’s concentrated, it’ll last you a long time.

So what can you do with it?

For a start, it is an excellent weed and grass killer. Make it up at about 10% (500mL in a 5L garden sprayer), add a few handfuls of salt, make the whole lot up to the 5L mark and away you go. Spray it on weeds and grass that you want to kill and you’ll start to see results within 24hr. And it doesn’t matter if some gets on the soil – there are plenty of things in the soil that will neutralize it.

And if you find something that will survive this brew (unlikely) then just increase the concentration.

It’s also an excellent chemical for rejuvenating driveways. Cement is essentially an alkaline composite. As it’s exposed to the sun and air it develops a coating of cement dust, largely composed of limestone (calcium carbonate). A 10% solution of hydrochloric acid will strip off this layer and restore it to pristine condition. A clean with a high pressure water cleaner afterwards will remove any water marks and give it a uniform look.

Have you had tiles put down and the tilers have smeared grout over the tiles? No problem – a 5% solution of hydrochloric acid will get it off easily.

4 thoughts on “Hardware Chemicals #1: Hydrochloric Acid

  1. How will it affect limestone, and what strength solution do you recommend for pet stains like old grey urine and rock hard faeces?

    • It will fizz and foam when you spray it on the limestone but it won’t damage it. If the faeces and urine is on the llimestone the acid will liberate it. 1 part in 2 or 3 should do it. But wear safety glasses and gloves

      • Thanks for that. I will try it. What is the after care? just a rinse with the hose or does it need to be a high pressure rinse?
        There is no garden bed so it will just slip between the pavers. Is that ok for my little dog?

Leave a Reply

Your email address will not be published. Required fields are marked *