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Caustic Soda ?!?!?!?!?!

Discussion in 'The Hokey Ass Message Board' started by ttarver, Apr 7, 2008.

  1. ttarver
    Joined: Oct 8, 2007
    Posts: 406

    from austin

    So, I got some Caustic Soda from a friend of mine. I am under the impression that I can use this to remove rust from old parts, sheetmetal, etc... I have never done this and would like to NOT melt the flesh off of my bones. Do you guys have any tips? Have you done this before? How do I dispose of this crap when I'm done? What kind of results can I expect? Am I dumb for trying when I should just spend days with a wire wheel, grinding until my fingers bleed!!!!????? Any help would be awesome as the bag of this shit sitting in my garage kinda freaks me out.

  2. Rootie Kazoootie
    Joined: Nov 27, 2006
    Posts: 6,052

    Rootie Kazoootie
    from Colorado

    Drain cleaner. Google is your friend.
  3. CRH
    Joined: Apr 30, 2006
    Posts: 551

    from Utah

    Caustic soda is drain cleaner, or Lye. I know it will remove anodizing from aluminum so you can polish the Al, but not sure on rust removal. It is pretty dangerous- don't get it on you and don't breath it.
  4. enjenjo
    Joined: Mar 2, 2001
    Posts: 2,351

    from swanton oh

    Back in my youth, I worked in a chemical factory. We used caustic soda and methelene chloride to remove rust, paint, filler from steel. DO NOT USE ON ALUMINUM. Great on paint and filler, so so on rust.

    Wear a rubber apron, heavy elbow length rubber gloves, a face shield, and a resperator at minimum. It will permanatly scar skin in seconds. Put it in a cut down plastic shipping drum.

    My advise, try something else.
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  5. pearl
    Joined: Sep 24, 2007
    Posts: 6

    from Austin, TX

    Before you start, get a huge jug of vinegar and keep it nearby. Vinegar will neutralize the lye if it gets on you (and it will!). It's not going to melt your skin off instantly or anything like that (unless you lay in it or something), but it does burn like hell and yes, will leave a scar! Safety glasses are also a must.

    It is going to heat up like crazy when you add liquid to it - you will need to let it cool some before you do anything unless your only plan is to soak things in it. It will also release some fumes so you should mix it outside and step away from it for a few minutes, it's enough to give you a good coughing fit in even small quantities. You can mix it with a wooden spoon or paint stick (or a yard stick if you are doing a big batch of it), but it will eat the wood if you leave the spoon in there. I'd try it in a small quantity first though to make sure it works before you try to deal with a huge batch of it.

    Disposing of it would depend on how much gunk is left in there once you get the parts out of it. Normally, I would dump it down my drain, but not with rust and gunk in there. My suggestion would be, once you are done, add at least an equal amount (more is better) of cheap cooking oil (any kind, even a big hunk of crisco or lard melted will work), stir it well (you will see a color change) and leave it sitting for a couple of days. It will make a "soap" type substance - nothing you would want to bathe with, but safer to throw away than plain lye. It should harden and may be a bit tingly to the skin should you try to wash with it, but nothing major.

    And don't worry about it being in your garage, I have a ton in mine now and have never had an issue though if the bag is open, it may clump from moisture. There is also a ton of safety information on lye on some of the soapmaking forums and websites.

    Hope that helps! Good luck!
  6. noboD
    Joined: Jan 29, 2004
    Posts: 5,880


    Caustic soda is what radiator and engine machine shops use to clean parts in hot tanks. Do not use it on aluminum.
  7. leadsled01
    Joined: Nov 19, 2004
    Posts: 1,121


    Pearl is right about the vinegar.. My brother used to truck caustic soda in his semi and would always carry a bottle full of vinegar just uncase.
  8. olskool53
    Joined: Mar 23, 2008
    Posts: 102

    from CT

    Had a helper burn his hands so bad he was out of work for 3 weeks. Nasty stuff! Buy some
  9. They add that crap to the drilling fluid in the oil field...I wouldn't screw with it if I were you as it is EXTREMELY volatile! We had some moron add hot water to it as he mixed it in the pits instead of cold water...he is now in the hospital with some nasty chemical burns.

    If I were you I would go for the aircraft paint stripper...or the grinder/wire wheel is a pain in the ass but a lot safer in a relative perspective.
  10. 325w
    Joined: Feb 18, 2008
    Posts: 4,240

    from texas

    It will take the first layer of you skin real quick. Been there done that.
  11. Halfdozen
    Joined: Mar 8, 2008
    Posts: 459


    Google electrolytic rust removal. Washing soda, water and a cheap battery charger. Works very well without removing sound metal, no nasty flesh-eating chemicals.

    Edit: Here's a sample-

    The soda/ water concentration affects the amount of current the battery charger puts out. Weaker solution= longer time to derust, easier on the charger. And don't use a metal bucket. I did once, the process left a ring of pinholes in the bucket at the top of the solution.
    I've found it usually leaves steel parts black, sorta like a black oxide finish. Prep and paint as normal. Never tried this to clean alloy parts.
  12. bbodybenny
    Joined: Feb 28, 2008
    Posts: 16


    My two bob's worth is you should just take your parts to a shop that has a caustic hot tank and have them dipped by them. It wont cost that much.
    The thread running through all these posts is the same, its nasty stuff that can mess you up. I wouldnt muck with it buddy, aint worth it.
  13. the SCROUNGER
    Joined: Nov 17, 2005
    Posts: 478

    from USA

    it will work- basically caustic soda is an extreme "base" solution, the opposite of an acid- yes, it eats rust, and is what many drain cleaners/uncloggers are made of- in the old days a "hot tank" had caustic soda in it as well, at most large local machine shops- the other method is an acid solution at the other end of the PH scale- I have used muriatic acid from hardware store, and it kicks ass and takes names on rusty parts- I'll post pics of results shortly

    use gloves, and use it outdoors in a tank, and submerge the parts

    you can also get it in crystal form and add water, as drain cleaner. The common "iron out" sink-toilet-tub-bathroom cleaners are actually a caustic soda solution

    to be honest, acid is easier to work with than caustic soda- buy a gallon of muriatic acid from hardware store, it costs $5-6 a gallon- mix it 50/50 with water in a large tank, and submerge your parts for a few days- pull them out each day to check on them- in 2-3 days the heaviest rust scale will be gone- I don't use acid full strength it's just too fumey- acid won't remove all grease and paint, only rust

    the caustic soda will remove everything
  14. the SCROUNGER
    Joined: Nov 17, 2005
    Posts: 478

    from USA

    derusting experiment with muriatic acid/water mix- I already did a few cylinder heads, valve covers, etc. in this tank, but these hinges and piston/rod were REALLY rusty so it was a challenge- this is what I started with

    4 hinges, one piston/rod- the hinges were outside for about 20 years, the piston/rod was an old tin plated piston, from who knows what ? was there at least 60 years buried in dirt
  15. the SCROUNGER
    Joined: Nov 17, 2005
    Posts: 478

    from USA

    removed the parts after 2 days, almost all rust was gone, wire brushed them and the rod and hinges were bright, but with some rust here/there- so dunked them again for 2 days- all the rust disappeared but grease in the tank started to turn the parts black

    all the rust is gone, leaving only pit marks where rust used to be- had I kept a closer eye on the parts and pulled them out sooner, or used a clean fresh solution to begin with- they would be brighter looking and not discolored from grease in the tank- this acid seems to last a long time, and doesn't freeze when left outside

    if that was an aluminum piston without tin plate, it would have been gone completely

    Attached Files:

  16. Mark in Japan
    Joined: Jun 19, 2007
    Posts: 1,415

    Mark in Japan

  17. James Curl
    Joined: Mar 28, 2006
    Posts: 369

    James Curl

    Oven Cleaner, which is what I use to degreese car parts is nothing but sodium hydroxide or lye. I have used Muriatic acid to derust, but when you wash the acid off with water it will flash rust again. I do not know what to use to neutralize the muriatic acid so I just wash wirh water.
  18. pitman
    Joined: May 14, 2006
    Posts: 3,999

    from Hampsha

    Something about adding acid, slowly to water (as in a Large amount of water) vs the other way around. HAMB-er reaction, never a good thing!
  19. docauto
    Joined: Dec 1, 2006
    Posts: 793

    from So Cal

    always add acid to water, if you add water to acid you will get a nasty heat reaction: DANGEROUS!
  20. the SCROUNGER
    Joined: Nov 17, 2005
    Posts: 478

    from USA

    true- I noticed water to acid, that's when it makes the most fumes and I have to get away from it quick

    acid to water, there's not much of a reaction at all and I can stand nearby and not get all fumed out
  21. T-Bone
    Joined: Mar 17, 2001
    Posts: 358


    Generally speaking, acids do a better job of removing rust than sodium hydroxide (caustic). In industry, Caustic is used for breaking down organic solids in food processing plants...which is what makes it so dangerous for your skin, that slimyness you feel is your skin melting. Caustic is a gnarly chemical to be handled with care.
    As mentioned, ALWAYS add chemical to water, not the other way around and eye protection is a must...undiluted caustic in your eyes wont make you happy; braille is hard to learn....
  22. rotorwrench
    Joined: Apr 21, 2006
    Posts: 629


    Acids can cause hydrogen embrittlement if used to strip hardened steels. That's why a strong base like sodium or potasium hydroxide is used in machine shops for engine related parts cleaning. Where the metal is not highly stressed, acid stripping can give excellent results if used correctly.

    My local Redi-Strip shop closed up and I sure miss him.
  23. Dan10
    Joined: Aug 14, 2007
    Posts: 386

    from Joplin

    FYI: Strong bases i.e. lye, drain cleaners, are DESENSITIZERS. This means that they will numb the skin, making it less likely to notice a burn until it is way to late. So even if you did not think you got any on you it is a good idea to wash all exposed areas (which there should be none because you should have a full mask, elbow gloves, rubber apron, etc.) very well with water or at least wipe off with vinegar. I learned the hard way.
  24. orange crush
    Joined: Jun 21, 2005
    Posts: 309

    orange crush

    Nasty stuff I owned a radiatior repair shop in the 70's. turned my fingernails a pretty shade of brown. also lost the feelings in both my hands for about 3 yrs. still have problems with my lungs. as I said nasty stuff. Carlg
  25. As far as the above, I learned this in 7th grade science class.

    "Do as you ought-er, add ACID to Water!" :)

  26. Moonglow2
    Joined: Feb 4, 2007
    Posts: 656


    The active ingredient in drain cleaner or lye is potassium hydroxide. Caustic soda is sodium hydroxide.

    Because of the exotherm involved with mixing water the rule is add the chemical to the water and not the other way around. Strong alkalais like sodium hydroxide are very dangerous to soft tissues particularly eyes because it is so miscible (spreads immediately). If you get it in your eyes it isn't a question of whether it will harm the eye but a question of how much damage it will do before it is flushed away with large amounts of water. Neutralizing sodium hydroxide with muriatic acid (hydrochloric acid) which is commonly used to clean concrete or brickwork turns it into sodium chloride + water or salt water brine.

    If you must use it be very careful with that shit.
  27. ttarver
    Joined: Oct 8, 2007
    Posts: 406

    from austin

    This place amazes me every time I log on!!!! You guys have offered some great info on this stuff. Sounds a little sketchy to me. I don't know if I will use it now or not.:confused: Any tips on storing this stuff? It came in pellet form in a paper bag. For some reason paper just doesn't seem adequate to keep this shit from getting out and murdering me in my sleep. hahaha.

    Thanks again fellas,

  28. the SCROUNGER
    Joined: Nov 17, 2005
    Posts: 478

    from USA

    that's why it works so good in mild form as soap- and also as a drain cleaner to eat through organic matter
  29. the SCROUNGER
    Joined: Nov 17, 2005
    Posts: 478

    from USA

    I was reading a few drain cleaner labels at Walmart yesterday, all of them used 2 different "hydroxide" chemicals in the same bottled product
  30. the SCROUNGER
    Joined: Nov 17, 2005
    Posts: 478

    from USA

    I keep my drain cleaner crystals outside in the shed, away from my kid, wife, pets, etc. Just reading label made it sound like nuclear radioactive toxic waste. If you mix up a batch of that stuff, you use it once then dump it out, to best of my knowledge. I also keep bottles of muriatic outside behind garage- if there's a spill it will be outside and away from living quarters, where it can be hosed down with water and neutralized- I keep the dunking tank covered with thick plywood lid. The acid tank seems to be less dangerous and lasts a long time, it's been out there now for months and still cleaned those hinges and piston/rod.

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