Announcement

Collapse
No announcement yet.

Phosphoric acid

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Phosphoric acid

    Having read the previous posts on rust removal, I am interested in trying the phosphoric acid, but I don't know where to get it. Is it readily available? Is it available under a brand name product? I don't recall having ever seen it, but I could have walked past a 55 gal. drum and not noticed it. My wife says I'm really good at doing that! I have never looked for it and just wondered where I might find it. Also, is it classified as a hazardous material? Sounds as though it could be. Any safety precautions? Thanks.
    There is no shortage of experts, the trick is knowing which one to listen to!

  • #2
    Ospho,Naval jelly,ect

    Comment


    • #3
      I got some from a horticultural supplier, as it is used in hydroponics as a pH adjuster. The bottle was labeled "pH down", but a look at the small print confirmed it to be nearly pure phosphoric acid.

      Comment


      • #4
        Phosphoric Acid

        When I was doing rusty car body work I used a metal preclean which was a mixture of phosphoric and hydrochloric( muriatic) acids.
        I recall that it came in plastic bottles and were about a pint/half liter.

        I would suggest that you go into a car body and paint supplier and ask- what do they recommend for neutralising body work. Ok, some may offer acid etch primer but insist!

        Again, I am doing my domestic chores for Brownie Points!!!!!
        SWMBO has supplied me with Limescale Remover which contains Sulphamic Acid 20%.
        This also works on rust/

        You could buy citric acid crystals from your local chemist/druggist as a simple alternative.

        Yes, darling, I haven't forgotten. Mutter, mutter

        Norm

        Comment


        • #5
          Readily available at Lowe's or Home Depot if you are in teh states.

          Check the concrete etch materials they have. I used "Seal-Crete clean n etch", but there are probably others.

          as for precautions... keep out of eyes. Otehrwise as you wish. I stick my hand in the diluted stuff ( 10 to 1 or more is fine) to fish out parts (ans rinse right after), but gloves will keep scratches etc from stinging.

          It isn't harmless, but far less immediately damaging than purple cleaner, for example, in the usual concentrations.
          1601

          Keep eye on ball.
          Hashim Khan

          Comment


          • #6
            Check the labels, concrete etch products may contain hydrochloric acid, which is nastier than phosphoric. Many of the lime removal products also contain phosphoric.

            If contemplating rust removal, the electrolysis method is simpler, safer and uses no acids with their potential problems. I would not use an acid rust removal process in my shop for the potential problems from the fumes. If you do use acid, use it in a separate area.
            Jim H.

            Comment


            • #7
              Myfavorite s Jasco "Metal Prep" because its made for rust removal and has gelling agents and inhibitors already added. It converts rust into a hard black coating you can scrub off with a wire brush or just leave there.

              Personally for heavy rust and scale I prefer a muratic acid pickle followed by a wrinse, neutralize in washing soda, and a power wire brush to clean bare metal - THEN an application of phosphoric acid until the metal is darkened or discolored, followed by a wrinse and a scrub with a fiber or plastic bristle brush. It's a lengthy seeming process but the work comes out rust inhibited and ready for paint. I keep the solutions in 5 gal covered plastic buckets out of doors.

              Do not use acids or rust promoting chemicals indoors around machine tools. You will be sorry for years. That's right: years.
              Last edited by Forrest Addy; 09-14-2006, 09:53 AM.

              Comment


              • #8
                As Forrest says, beware hydrochloric acid. Even the closed bottles outgas small quantities of fumes and this results in rust appearance on any exposed steel surface in the room. Phosphoric doesn't seem to be so obnoxious, it doesn't have noxious fumes but is considerably more expensive than hydrochloric acid.
                Steve

                Comment


                • #9
                  Best place to get it is a hydroponics supplier. Get the full strength type (85%). It's not bad priced at $15 per liter here. To use it cut about 50/50 with water. Strange stuff as the density is 1.6 times that of water. The liter jug is way too heavy for it's size.
                  Free software for calculating bolt circles and similar: Click Here

                  Comment


                  • #10
                    Phosphoric acid

                    Originally posted by JCHannum
                    Check the labels, concrete etch products may contain hydrochloric acid, which is nastier than phosphoric. Many of the lime removal products also contain phosphoric.

                    If contemplating rust removal, the electrolysis method is simpler, safer and uses no acids with their potential problems. I would not use an acid rust removal process in my shop for the potential problems from the fumes. If you do use acid, use it in a separate area.
                    Jim makes a good point here. I once made some acid flux for soldering galvanized sheet and put the bottle on the shelf under the tool board that hung on the wall. Everything got a mist cote of rust that kept coming back long after the bottle of flux was gone. It just kept coming back.
                    Jim (KB4IVH)

                    Only fools abuse their tools.

                    Comment


                    • #11
                      BTW, phosphoric does NOT promote rust the way otehrs do.

                      I have had a piece of metal near the jug with no rust appearing. With muriatic (HCl) or sulphuric, rust appears all around.

                      OK with me if you want to be cautious, but I don't think you need to.


                      Yes, ALWAYS check the labels..... Products change without notice.

                      I think the environazis are "after" phosphoric acid for banning, as it could result in excess phosphorus in wastewater.... remember the furor over "phosphates" that got various cleaning products reformulated or effectively banned, notably TSP.
                      1601

                      Keep eye on ball.
                      Hashim Khan

                      Comment


                      • #12
                        I can buy TSP at the grocery store here.
                        Free software for calculating bolt circles and similar: Click Here

                        Comment


                        • #13
                          The hardware stores here have "TSP substitute", but none of the real thing.

                          The substitute is some carbonate, and actually works pretty well, better than most "environmental substitutes".

                          The usual "environmental substitute" cleaner is a placebo to mix in water to make you forget you are now rubbing and scrubbing 12 times harder and getting half as much cleaned. Similar for other "environmental substitute" products.
                          1601

                          Keep eye on ball.
                          Hashim Khan

                          Comment


                          • #14
                            I haven't bought any in a while. We are going grocery shopping after work. I'll have to check and see if it is still on the shelf. It's good stuff to put down my drain as it encourages algae growth in my treatment lagoon.
                            Free software for calculating bolt circles and similar: Click Here

                            Comment

                            Working...
                            X