<VV> Derusting---Was "I was wrong..." Long

Mon May 16 14:32:15 EDT 2005

Washing Soda is Na2CO3 or sodium carbonate, about pH 11.  it is a salt. 
This high pH salt was used to help clean clothes.  not less causic 
chemicals are used.  now it is commonly used in fabric dyes and as buffers 
in marine aquariums.  You can still get it on the laundry isle or in 
specialty shops like art stores and aquarium stores.

Sally

On Sat, 14 May 2005, J R Read_HML wrote:

> What the heck is Washing Soda - do you mean laundry detergent?
>
> Attachments (if any) are scanned with anti-virus software.
>
> Later, JR
>
> ----- Original Message ----- From: "WadeHalsey" <HiHal at adelphia.net>
> To: <virtualvairs at corvair.org>
> Sent: Saturday, May 14, 2005 5:53 PM
> Subject: <VV> Derusting---Was "I was wrong..." Long
>
>
>> 
>>> also, you can use normal table salt, but water
>>> softening or sidewalk salt does MUCH better....and
>>> it's cheaper too.
>>> 
>> I have never heard of using table salt in any derusting solution! My notes 
>> on the topic gathered over the years suggest using common WASHING SODA 
>> instead. Following are my notes on the topic from this and other 
>> forums-----Wade Halsey
>> 
>> 
>> "Anyone restoring a rusty old car should learn about this type of rust 
>> removal. It uses chemistry to make work easier. You will need a large 
>> container to hold the solution, a battery charger such as a 10 amp, 
>> sacrificial piece of steel, such as a section of stainless sink because 
>> stainless lasts longer. Or use an old stainless pot or pot lid. You want a 
>> piece of steel with a lot of surface area. Then some washing soda from the 
>> grocery store.
>> Fill the container with water and add one tablespoon of washing soda per 
>> gallon of water, more soda is OK. Put the steel in the water and put the 
>> red or positive (this is important) clip from the charger on the stainless 
>> steel. Keep the clip out of the water since it is made of copper and will 
>> disintegrate fast. Take the rusty part and put it in the mix and attach the 
>> negative clip to it. If the clip goes in the water it's OK. Plug in the 
>> charger and wait. Don't let the part and the stainless steel touch. You 
>> will see bubbles start to come off the part within minutes. If you see 
>> little bubbles it's working. Give most parts a day and they come out with 
>> no rust. This process turns the rust into a black substance that you can 
>> wash off with a stainless steel wire brush and a scrub pad. Wear gloves 
>> while cleaning or the black stuff will stain you fingers. The rustier the 
>> part the longer it needs to soak. This process will remove paint and all 
>> the rust and will not damage the good metal. It is much gentler on the 
>> metal then a wire brush on a drill and is a lot easier. When the solution 
>> gets dirty dump it on your lawn. The grass likes the iron and gets real 
>> green.
>> The rust removal system works great. A note of caution. The bubbles coming 
>> off the positive and negative electrodes in the solution are Oxygen and 
>> Hydrogen. They aren't poisonous to breath but the Hydrogen gas is extremely 
>> flammable. Do this process in a well ventilated area. Air it out before you 
>> do any gas torch or arc welding operations.
>> One problem is that once you clean the part with water and a scrub brush 
>> you will need to dry it and be ready to paint it with a primer or it will 
>> flash rust. Remember, you can leave it in the solution till you're ready to 
>> clean it. This process will not hurt good metal only rust. I took a rusty 
>> rim for three days and it looks new.  Jerry Mannix White 56 -
>> 
>> Question: How does this solution affect other materials like rubber 
>> bushings or plastic parts. In other words, do steel parts to be de-rusted 
>> have to be completely stripped down? And one last question, what about 
>> embrittlement of parts like springs? Is this method safe to use on 
>> suspension parts etc?
>> It doesn't.  This is basically (really there is a lot of other stuff going 
>> on also, as it is a double compound replacement reaction) an 
>> electro-chemical process that changes the ferric oxide (Fe2O3, scaly red 
>> rust,) to ferrous oxide (FeO, black hard rust).  The solution sodium 
>> carbonate and water is a buffered basic solution with a PH of  10.  So, if 
>> an alkali (basic) mixture won't hurt it, it is ok.  It does not affect the 
>> strength or hardness of the steel or iron, beyond that already done by the 
>> original rust.  You are simply coating the part.  Anodizing aluminum is a 
>> similar process although it is done through a chemically different process. 
>> Aluminum or any other reactive metal in this bath, will pit extremely fast. 
>> Jim Davis
>> You can use any steel but stainless steel lasts longer. Normal steel like a 
>> cookie sheet will last about a month and corrode away. Get an old stainless 
>> kitchen pot at a yard sale.  Don't use baking soda, WASHING SODA makes a 
>> much better solution. Baking soda works but will slow the process and you 
>> need to keep adding it to the solution you have. The purpose of the washing 
>> soda is to create an electrolyte solution, washing soda is a better 
>> conductor. It also costs less then baking soda. You won't hurt anything by 
>> using baking soda but you may have a higher electric bill due to the fact 
>> it will take longer to de-rust each part. With either solution you use you 
>> have to change it or add more soda every few weeks to keep it working ant 
>> top efficiency.
>> 
>> I found this technique (sodium carbonate and electrolytic reduction) on the 
>> antique stationary engine mailing list.  I was intrigued, but also 
>> distrustful.  Surely it was corrosive, hazardous, or something similar. All 
>> the chemical derusting techniques I had seen involved acids and corrosion 
>> of good metal.  The stories thrown around suggested that this
>> was not so with the washing soda method.
>> I searched and found that museum conservators with irreplaceable ferrous 
>> artifacts prefer this method precisely BECAUSE it does not allow any 
>> corrosion of intact metal.  If done with Sodium Hydroxide (lye) instead of 
>> with Sodium carbonate, it's actually capable of converting iron oxide back 
>> into metallic iron.  (NOTE:  I DO NOT
>> RECOMMEND USING LYE FOR THIS PURPOSE.  Its advantage over washing soda is 
>> largely theoretical and it is vastly more DANGEROUS) For that matter, the 
>> process does not remove the corrosion products; they are instead
>> electrolytically reduced from rust to black magnetite, but they stay right 
>> there on the metal until you rub them off with a stiff toothbrush or 
>> something similar.
>> 
>> The solution will have no effect on rubber, but may roughen the surfaces of 
>> some plastics.
>> Remember that the reaction is done in a reducing bath with an alkaline 
>> electrolyte.  Hydrogen embrittlement is
>> from exposure to acids.  (free hydrogen radicals attacking metal) 
>> Admittedly, the electrochemistry alters the case somewhat, but emperically 
>> I'd be willing to argue against measurable ion migration out of the metal 
>> itself over the amount of time that derusting is performed.
>> The areas to be derusted need to be free of anything that would inhibit the 
>> solution making intimate contact with the
>> metal itself.  Free flow of electrolyte past the surfaces is important in 
>> maintaining a constant field strength and solution concentration over the 
>> surface being treated.  Greasy metal is a bad idea. So is a significant 
>> covering by anything else, although I've seen it do a fine job in removing 
>> paint after immersion for a week or so.
>> One other huge win of this process over any other rust removal procedure 
>> I've found is that it reverses the swelling that binds rusty parts 
>> together. The problem is caused by the simple fact is that rust is bigger 
>> than the iron from which it came.  Accordingly, a rusty bolt swells in the 
>> rusty hole in which it is threaded and no longer unscrews easily.
>> The electrolytic reduction process turns the rust into magnetite, which is 
>> both mechanically weaker and smaller than rust.  Usually you can unscrew 
>> parts that have rusted together if they're carefully treated in the bath 
>> for a while.  My test case for this was a pair of otherwise-good 140 HP 
>> exhaust manifolds which had bolts screwed (and rusted) into the drilled-out 
>> stud holes.  After cooking for about a week the bolts unscrewed with 
>> moderate effort. Rad Davis
>> Jim Davis wrote: Rad got me started with this a couple years ago.  It works 
>> as  advertised.  Be patient a really rusty part will take 24 to 30 hours to 
>> completely harden. For those young ones who have never hear of washing 
>> soda; it is sodium carbonate.  It that chemical we use in swimming pools 
>> to raise the PH. Jim Davis"
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~~Sally Willaims~~~<}}><~~~~www.unm.edu/~sbuna~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
when those pesky Mongolians try to invade, they'll come to the wall and 
say "Oi! We can't invade China! They've got cute fishies!" 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~