Muriatic Acid

cbxjeffcbxjeff Member Posts: 14,689 ✭✭✭
edited September 2003 in Ask the Experts
Per my post of a week or so - this stuff works great. Yes, smells like he*l. A couple of more questions about it's use. Can I assume that it weakens as it is being used? It's been 43 years since I've had a chem. class but with the chlorine coming off, I guess after a while I would end up with water and iron in some form. Also, is is safe to use on brass?

Thanks for all the help guys. I'm working on a couple of pre-1898 pistols. Not worth a whole lot, but I'm really having fun with this project.

cbxjeffIt's too late for me, save yourself.
It's too late for me, save yourself.


  • queeksdrawqueeksdraw Member Posts: 274 ✭✭✭
    edited November -1
    I'm Sure that muriatic is a deluted form of hydrocloric and it is not good to breathe it in. It is used in the masons trade a lot and will keep in a plastic jug for years.

    You'v gota kill it to grill it
  • HangfireHangfire Member Posts: 3,010 ✭✭✭
    edited November -1
    Muriatic acid works great on brass. Removes all the oxidation, but will lightly copperplate it, leaving it kinda pink. This is due to the contamination from the corrosion. This is easily removed by polishing or scrubbing with a brass brush and metal polish. The copper can also be removed with an additional application of fresh acid and a clean brush-Bob

    Gun control is a steady hand
  • chunkstylechunkstyle Member Posts: 2,463 ✭✭✭✭✭
    edited November -1
    Don't breathe the stuff. The gas is not as bad as chlorine, but it is HCl gas, and turn the moisture in your lungs into more muriatic acid. Not good. When it's used on brass, it preferentially dissolves out the zinc in the brass, leaving the copper. It can accelerate the "greening" of copper and copper alloys. On iron, it turns it to iron chloride, a brown crumbly stuff. In other words, corrosion. This stuff is best used to clean masonry surfaces. If you want a good cleaning chemical in aqueous solution for metals, try trisodium phosphate (TSP). But you are best off sticking to organic solvents, like naphtha (paint thinner).

    "Go to Lakedaemon, stranger passing by;
    And say there, that in obedience to her law, here we lie"
  • v35v35 Member Posts: 13,200
    edited November -1
    I've heard of HCL (Muriatic) being used to derust severely rusted guns like battlefield dug-ups. I've also heard of springs breaking easily after this treatment.
    Hydrogen from the hydrogen ion penetrates the boundries or interstices of steels'crystaline structure causing hydrogen embrittlement.
    The embrittlement can be reversed by baking after an acid treatment.
    The temp and duration of the bake would have to be researched.
  • wundudneewundudnee Member Posts: 6,012 ✭✭✭
    edited November -1
    queeksdraw is right, muriatic is basicly the same as hydrochloric acid. HCL is just a more refined reagent grade. Muriatic does weaken as it reacts with rust, calcium and magnesium products. Just put what you are going to use in a separate container and don't pour it back into the original container when you are done. It is a wonderful product to clean stained plumbing, open plugged drains and remove water marks (calcium deposits). It's also cheaper than most of the shower cleaning products and better.

    When you are done it does no harm to dispose the used muriatic down the drain. Flush it with lots of water. Water neutralizes it readily if you happen to get any of it on you. Wear rubber gloves and goggles, it is not as toxic as many acids to your skin but it will work on it.

    It won't hurt brass in the least, but as stated it will stain it a little. Muriatic will clean and save a lot of brass valves and plumbing fixtures.

    Now if you want to get radical with brass and copper you can clean it with Nitric acid. Nitric is a different much more dangerous to use acid. It will take off layers of brass and copper until it is gone. You can drop a copper penny in nitric acid and the smoke rolls until the penny is gone. Nitric will also eat proteins out of your skin and turn it bright yellow.

    Old? First you forget names; then you forget faces; then you forget to pull your zipper up; then you forget to pull your zipper down.
  • fort_knoxfort_knox Member Posts: 263 ✭✭✭
    edited November -1
    It works great for bringing the pH down on water that is on the akaline side (high pH). I have a 500 gallon spa that runs high after changing the water periodically. The well water here is akaline.

    The spa stores won't endorse it since it is so cheap compared to the high priced granulated "pH Reducer" that they like to promote (and they also like to point out it's hazardous/dangerous nature). The expensive stuff is a hassle to use also. I just pour in a couple of 8 ounce shots of acid after a fill and I'm pretty much on the money for about $0.25 verses $10.00!

    Also, it takes the glaze off of concrete nicely. I epoxy coated my garage floor (epoxy paint), but had to etch it first w/Muriatic Acid.

    The paint store suggested a water/acid ratio of 8:1, but it was not productive. I went 50/50 and it really did the job! It stinks like H*** as someone said here, but w/good ventilation it wasn't too bad.
  • captkirk3@dslextreme.com[email protected] Member Posts: 3,804
    edited November -1
    Used the Stuff in My Swing Pool for Years....Arizona Water is hard as can be...Found out the hardway not to buy it buy the case, as it delutes in the Bottle over a period of time...Did'nt know that it would Vapor off thru the Pores on the Plastic Jug...in a few months time it was oderless...and worthless..........

    Captain Kirk, Tech Staff
  • jsergovicjsergovic Member Posts: 5,526
    edited November -1
    I have a respirator with the right cartridge.
    Takes the sting right out of the gas, but you still need oxygen.
    Check any industrial supply for the respirator; there'll be info on correct filters.

    3M 60922 Combination Cartridge/P100 filters for Acid Gases and Particulates on a half facepiece (6000 series) respirator do a nice job.

    3-M has a great support line if the counter people aren't experts.
    I get'em at Grainger, online, UPS'ed to the house.

    "I don't know" is the source of all knowledge. - "Data"
  • fort_knoxfort_knox Member Posts: 263 ✭✭✭
    edited November -1
    quote:Originally posted by [email protected]
    Vapor off thru the Pores on the Plastic Jug...in a few months time it was oderless...and worthless..........

    Captain Kirk, Tech Staff<P><BR>

    Same thing with carbonation in plastic soda containers after awhile.

    The polymeric chains in the container have a strong covalent (ion sharing) bond between their molecules, but the weaker secondary bond (van der waals bonding) between the adjacent chains is the "weak link" in the structure that allows gases to pass through in time.
  • MISDAGINMISDAGIN Member Posts: 17 ✭✭
    edited November -1
    I use muriatic acid(1 acid:10 H2O) to pickle firearms prior to polishing for rebluing. It's cheap, safe, and efficient. A quick dip, usually 30 seconds or so, and the blue is gone and polishing is much easier. The steel seems to accept the bluing process much more readily also. I thoroughly scrub the dipped pieces after removing them from the acid mix, especially the bore. Been doing this for 20+ years without any adverse effects. DO NOTuse on aluminum! I have also used this mix to remove plating, but not on firearms. I just recently used it to remove zinc plating from the interior of a water tank that I plan to use as a smoker. Do this outside and stay upwind. Inhaled zinc fumes, either burned or vaporized, can be toxic. This stuff really stinks!

  • competentonecompetentone Member Posts: 4,651 ✭✭✭
    edited November -1
    quote:Originally posted by MISDAGIN
    Do this outside and stay upwind. Inhaled... can be toxic. This stuff really stinks!

    For your safety: Go to Lowes or Home Depot; get a resperator designed for "acid gas"--it will cost you around $20. Pick up a decent pair of safety glasses or goggles (one designed to protect from "splashing") if you don't already have a pair.

    Use your safety gear when working with the acid!
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