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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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How to make steel bolts rust so a nut is harder to remove
I am trying to test various penetrating oils to determine which is more effective at loosening a nut when the nut and bolt are rusted/corroded.
I have tried many different methods to make nuts and bolts rust or corrode but I have not found a good way yet. After many trials and errors I determined that common household laundry bleach seem to be something I should use, then I read that it could be more effective if the pH balance was acidic so I mixed Bleach and Muriatic acid, later I read in this forum what a bad idea that was. Are there any good recommendations so that I don't harm myself and/or my family by continuing to experiment with various chemicals, not knowing what I am doing or anything about chemistry. Also, if possible, it would be nice to have some general idea of mixture ratios and things like does the bolt need to be completely covered or partially exposed to air, or completely exposed to air and the rusting solution sprayed or misted over the bolts, and, duration, does the mixture need to be changed every day or every few hours, should the process take hours, days, weeks, etc. Thanks in advance, I really appreciate your advice.
my involvement is pure research, not business or hobby - St. Paul, Minnesota, USA
December 2, 2010
December 3, 2010
Rick,
Before you kill yourself, your family and neighbors...STOP WHAT YOU ARE DOING!
Mixing bleach with acids was about as dangerous as it gets, you're lucky you aren't already dead. Non-chemists should not be playing with hazardous chemicals in the home, it should be done under controlled laboratory conditions where all the right health and safety gear is available in case something goes wrong.
If you want to rust some nuts and bolts, first of all make sure they are plain steel nuts and bolts, not coated with anything such as zinc or a clearcoat. If you are not certain whether they are or not, abrade them. Then immerse them in a simple salt solution, about 5% salt will do. It won't take long for the rust to form and you won't have killed anyone in the meantime!
Aerospace - Yeovil, Somerset, UK
Doesn't immersion block the oxygen which speeds the process? Like the ship Titanic preserved at the bottom of the (salt water) ocean. The bolts are plain steel, they come with a coating of oil which I wash off with dish soap, taking care to clean the threads of the bolt and the threads in the nut.
My current theory for the speediest process to make the nuts stick to the bolts is to:
a) wash the oil coating off
b) spray the nuts/bolts with a mixture of 50/50 Bleach and Salt Water. I might try adding OxyClean to the solution to see if it helps.
The idea would be to spray several times a day and maybe try various ways to keep the bolt damp but still exposed to oxygen, like putting the bolts on a spongy type surface that holds the solution and maybe covering them with a similar material as long as the material allows plenty of oxygen to get to the bolts. And, assuming this will take about 30 days.
- Minnesota
December 3, 2010
December 7, 2010
Hi Rick,
The water you get at home will contain oxygen dissolved in it. Adding salt will accelerate the process, you really don't need to do anything else. The Titanic is a bit misleading, there are a lot of factors that affect the rate of rusting under the sea, the main one there being the temperature of the water.
Have a look at the Science Projects section on this site, there is plenty of advice on how to rust nails, nut, bolts, coins, etc. It seems that American schools love to try and dissolve things or make them rust. The important thing to ensure you get things corroding nicely is to make sure that the corrosion preventative oil is completely removed.
Unless you have experience with playing with bleach then I would really leave it alone, you could potentially release some very toxic gases, which will kill if inhaled in sufficient quantity (look up chlorine safety data to give you a clue).
Aerospace - Yeovil, Somerset, UK
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