Muriatic Acid

[little blue choo]

I finally set up my acid cleaning station today. Put in 2 gallons of water and then added 1 gallon of acid. Hope this is the right ratio. My question is how long do you leave your metal in the tank and if you don't get back to it in 24 hours will it do any damage. I am using 16 gauge P&O hot rolled steel.
Thanks
Rick

[Capstone]

So with "the dip" as I call it, so long as the metal is fully submerged, you can leave it there for days will no problem. But with the acid that strong, it shouldn't take more than an hour. Use protective arm length approved gloves, goggles and long clothing preferably with a plastic apron. little splashes will ruin clothing over time and definitely have a water hose nearby to quickly wash yourself if you get splashed on your skin.

I didn't measure it out specifically, but mine is probably around 10:1 and still only takes a few hours. 2:1 is probably a little caustic and overkill.

While you can leave stuff in the dip; do not leave any metal objects nearby outside of the dip; they will rust very quickly. The fumes will attack all forms of carbon. Only plastic and wood will survive and even plastics will discolor over time. (see the pic)

The minute the pieces comes out of the dip, rinse it with water and use compressed air to thoroughly dry it. And, don't try to rinse and dry too big of a batch either. you'll end up with the last pieces getting flash rust.

2015-09-27 07.49.51.jpg

[abmetal]

Muriatic acid will dissolve aluminum also. Take a penny, grind a little spot on the edge just through the copper cladding to expose the aluminum and drop it in the muriatic acid. Then take it out the next day and see what you have.

Allen

[steel 35]

I leave things in until morning pretty commonly, and someday's morning is close to noon.

I cut quail and want them to rust; found if I pull them and leave them just over the dip, they wont rust fast enough, but pull them rinse then put them back over the dip and it gets done.


Steel FX; Has a few videos on how he uses it with ratios too.

[OTHill]

Why use acid when you are using P and O steel?

[little blue choo]

Thanks Guys. Great information. I set it up outside and will change my ratio later. As for why use it on P&O, I like to polish and use dies and candy paint and if you use the acid on the P&O it will polish up much quicker. I tried it today with two exact same pieces and the one that was in the acid overnight polished in less than 1 minute the other one took over 3 minutes and took a lot more effort and I hate side grinders and flap disc.
Thanks
Rick

[gamble]

Lately I am using P&O steel and it's great since there is no milk scale. But I still let them soak in acid for awhile. Helps eat away at dross and saves me money on flap discs.

[Nacs Fab]

Biggest mistake I ever did was use this acid in my shop. Sounds like you made the best choice and use it outside. It rusted everything, even some of my hand tools if I left them out for long periods of time. I had a large poly cattle trough that had a brass drain plug. I loaded the vat and let it set a few days. I checked on it one morning and found the drian plug had leaked a large amount on my shop floor, and if flowed to the garage door and out into the gravel driveway. It cut a 1/8" deep channel about 12" wide. Stupid mistake.

I didnt think about how high the level was once it the vat was loaded and it eventually ate the plug. Never again.

[dustywill]

Lately I am using P&O steel and it's great since there is no milk scale. But I still let them soak in acid for awhile. Helps eat away at dross and saves me money on flap discs.

Love the P&O myself. I don't use flap discs to get off dross. I use a knotted wire brush and will never go back to acid or flap discs for dross. The acid is no longer a step I take. I don't have to dry my pieces and the flash rust that inevitably ended up on my work doesn't happen.