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Removing Rust

Started by Qweaver, January 14, 2015, 10:22:30 AM

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Qweaver

I'm trying to save 20 u-bolts that have fairly heavy rust from salt water emersion.  These bolts cost $5 each so are worth saving.  I am chasing the threads and they are coming out fine, but the un-threaded area is covered with rust scale that I would like to remove so that paint will hold.  I know that acid will dessolve rust, hydrochloric I think.  But where do i get it?  Is there a better way?  I have many other grade 5 and 8 bolts that I 'd like to treat also.  Mainly 1/2" dia. or larger.
Why do I hate hurricanes...let me count the ways.
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

pineywoods

Plain old vinegar from the grocery store. put them in a plastic tub, cover with vinegar, wair 4 or 5 days...
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

Gadrock

Go to the hardware store  and ask for ACID. They will give you a 1 gallon container of Muriatic Acid which is a diluted form of a more dangerous version. There are still some dangers here ...but with safety measures ....the project can easily be conducted.

How do I know?
   I am a blacksmith. Sometime projects must be presented without any scale or rust what-so-ever.

How to use?
   Water and Muriatic acid in various amounts...experimentation here...placed into a heavy duty PLASTIC container where it will completely cover the project. Here I prefer to use a :bus boy tub like is used in a restaurant, others can be okay too I guess. This tub is relatively inexpensive at Sam's, restaurant suppliers, etc.

How long?
   From minutes to hours...depending upon of remaining concentration.   But for me if it is not happening within 15 minutes the solution is used up or too dilute. Iron particles reduce the strength.

Safety measures!
   Fumes are horrible! Do not breathe! I do not use a respirator and I do not breathe in over this source. The vapors can travel across a shop or in confinement to cause tremendously accelerated rusting  on unprotected surfaces.
   Rubber type hand protection is advisable but I use none. With limiting exposure to skin with diluted material and quick cleanliness ...well I say "Let the user beware of dangers"
   Eye protection is a must. Have a good volume of fresh water available at all times to rinse with. Even the newly cleaned metal must be washed and neutralized.

Disposal
    You are gonna wake up every environmentalist in the country by just reading this. Mainly the secret is to neutralize the ions and the other things so that they are safe, which may be done by the addition of baking soda or lime.

Other thoughts
    Since you would be outside you may notice that small spils on concrete may turn green. Generously washed with water and then neutralized if you want to, while NOT wading around in the stuff with the wrong footware is a consideration.
   Certain plastics harden and crack when exposed to this product for extended time.

Will I use this again?
   Heck yeah. Removes scale and rust like you cannot believe. It removes chrome from hydraulic cylinder shafting. And is a real time saver for me. PLUS I am familiar with the concentrated form and what it can do. SO use it diluted somewhat.

Be safe

David G

carry on
LT40 G18,   bent Cresent wrench,   broken timing light
Prentice 280 loader, Prentice 2432 skidder, Deere 643J fellerbuncher, Deere 648H skidder, Deere 650H Dozer

4x4American

be careful with that muriatic acid that stuff is not healthy to breathe in. 
Boy, back in my day..

4x4American

I would wire wheel the bolts before I started being a chemist. 
Boy, back in my day..

Qweaver

A local hardware has 31%  Muriatic acid. I have no clue how strong that is.  I guess I'll try it and see. $7 a gallon... not bad if it works.
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

Lazy logger

You could try electrolysis if you wanted as well. Check out this video.

https://www.youtube.com/watch?v=HSPrum7LKWk
I know the voices in my head aren't real,but sometimes their ideas are just absolutely awesome!

Just Me

 I use a product I get at the parts store Called "OSPHO" Its a rapid oxidizer, eats the rust, leaves the good metal alone. I reuse it many times before getting new. I put it in a container/tray and let it soak, more time for more rust, pull it out wash it with water and pour the OSPHO back in the jug through a paint filter.

It is acid based but not so bad to work with, $26 a gallon. Handy stuff.

kevin19343

I had some old rusty hand planes and I soaked them in a tub of vinegar overnight. I scrubbed them lightly with a Scotch Brite pad the next day and they came up amazingly clean.

When your done scrubbing you have to neutralize the metal in a bath of baking soda and water for around 10 minutes or so. If you don't do this the metal will start to rust within minutes.

You can achieve the same results much faster with stronger acids but the risk is higher too.

shinnlinger

Shinnlinger
Woodshop teacher, pasture raised chicken farmer
34 horse kubota L-2850, Turner Band Mill, '84 F-600,
living in self-built/milled timberframe home

Jeff

What are the u-bolts for? U-bolts that are used for any kind of torque environment on an automobile need to be replaced if they are taken apart. Just like with head bolts. Something like for leaf springs or something, you are putting your life and other lives at risk if you are reusing u-bolts.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

DeerMeadowFarm

I've used the electrolysis when I used to restore garden tractors (before buying a farm, woodlot and before we had a child; y'know, when I had time!) It works awesome.

But I agree with Jeff; most companies will warn you about reusing u-bolts on axles. $5 each is cheap if someone's life is riding on them....

My $.02

Dave Shepard

Study up on mixing water and acid, if you aren't already familiar with it. Mixing it incorrectly can cause a violent exothermic reaction. Some one on another forum lost a friend a couple of days ago when he was trying to unclog a sink. The acid sprayed back violently and it killed him.
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

Gadrock

All of the above warnings about acids ---water---dilution ---safety should be highly considered. And then consider them some more!

And familiarize yourself when diluting as things can get going really fast (part of that exothermic thing).

One of the really bad things is: When things get going bad with acids and explosives, the level of badness increases much faster than imaginable. The you start breathing in that bad stuff. Most likely you won't die right there but you will in a hospital days later while in severe pain.

The main thought here is be safe.  Only clean parts that are not life/safety critical.

David G


carry on
LT40 G18,   bent Cresent wrench,   broken timing light
Prentice 280 loader, Prentice 2432 skidder, Deere 643J fellerbuncher, Deere 648H skidder, Deere 650H Dozer

snowstorm

Quote from: Jeff on January 14, 2015, 04:57:00 PM
What are the u-bolts for? U-bolts that are used for any kind of torque environment on an automobile need to be replaced if they are taken apart. Just like with head bolts. Something like for leaf springs or something, you are putting your life and other lives at risk if you are reusing u-bolts.
i agree but there not hearing it

Lazy logger

Me too, I am betting there for a dock if it's caused from saltwater.
Hope it's not axles.
I know the voices in my head aren't real,but sometimes their ideas are just absolutely awesome!

Kcwoodbutcher

When mixing acid and water always add the acid to the water, and do it slowly. 31% hydrochloric acid is very concentrated. The highest concentration attainable is 37%.
My job is to do everything nobody else felt like doing today

jmiller

I use phosphoric etching acid.   Its 9 bucks a half gallon, 24 hours after application wipe the dust off and paint.
Jason Miller

Corley5

By the time you buy the chemicals and spend the time to clean the bolts you'd be farther ahead buying new ones.  If they're not in a critical area where they should replaced I'd use a wire wheel or sandblast them.  For a 100 bucks I wouldn't waste time cleaning them.  I'd buy new ones.
Burnt Gunpowder is the Smell Of Freedom

gimpy

I'm lazy and have time.

I use Electrolysis to remove rust. Greatest trick I learned in years. I'm old and tend to have plenty of rusty parts and tools. I could hang 8-10 of the u-bolts at a time and have them all clean overnight. Without acid eating the metal.
Gimpy old man
Lucky to have a great wife
John Deere 210LE tractor w/Gannon Box

69bronco

I second Jeff, if these are spring bolts :o do us all a favor and scrap em.

Al_Smith

Citric acid is very good rust remover .

As far as u-bolts I've wire wheeled them on the threads .If they were pitted badly they get thrown in the scrap heap .BTW never seeze is your friend ;)

Qweaver

Quote from: Jeff on January 14, 2015, 04:57:00 PM
What are the u-bolts for? U-bolts that are used for any kind of torque environment on an automobile need to be replaced if they are taken apart. Just like with head bolts. Something like for leaf springs or something, you are putting your life and other lives at risk if you are reusing u-bolts.
These are new bolts that just have rust that I'd like to remove so the paint will last.  The threads are OK.   But on the topic of replacing when used.  I remember learning that you should in my Automotive classes.  BUT,  I raced cars with 13 to 1 compression ratios that the heads came off of on a regular basis and I never replaces those bolts and the only time that the head gasket failed was when I grossly overheated the engine.  I used ny-locs on every bolt and reused them also...never had one come loose and the stress and vibration are pretty high on a formula car.
If the threads on a bolt are compromised then I would not reuse it.  I have built many, many trailers and don't recall reusing u-bolts but if the threads were good...I would.  If a bolt has not been loaded beyond it's yield strength,  why not?  Remember the ultimate tensile is far beyond the yield.
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

prsv07

   I use muriatic acid for swimming pools which is basically concentrated hydrochloric acid, which implies that you should be very careful with it.   It is NASTY stuff, so use it outside.   And of course use eye protection. If you get one whiff of it, you'll know very quickly not to breath it in.
   Submerge the parts in muriatic acid and watch until the rust is all gone and you have just bare iron.  Should take only a few minutes.   Using pliers(of course not your fingers), take the parts out of the acid and dip in a solution of water and baking soda(sodium bicarbonate) for a few minutes to neutralize the acid.  Then rinse off the baking soda.  Dry and coat with oil to prevent further rust. To get them dry quickly , put into the oven for a few minutes.   
   If you get any muriatic acid on your skin,  you can wash it off easily.  It is soluble in water.   If you didn't wear eye protection and get some in your eye, IMEDIATELY flood your eye with water. I can't give any medical advice, but it would probably be a good idea to go to a doctor. So wear eye protection!!
   You can pour the used acid on the dirt and hose it down some.    It is  neutralized by  minerals in the dirt.   You can also pour it down the toilet.  It will also get neutralized there.  It might even clean the sewer line some.  It won't pollute anything because it gets neutralized quickly .

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