A bit of chemistry

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Pevehouse

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Hello all, this isn’t exactly a machining question but since I go to you guys with those questions I figure maybe there’s a chemist or two in here. Ok, so I’m building an automatic transmission that has sat out in the elements for a while and I have some internal drums and things that have a fair bit of rust on them, but not in any critical areas. I have been thinking about ways to remove the rust and it seems a dip in some ospho blue has worked in the past however I will need a way to effectively neutralize the acids once removed from the bath. Getting mixed information on the web. My thoughts were use a bath of mineral spirits followed by an oil bath. Trying not to use water since that will pretty much undo what I just did. Would love a little guidance or at least some different opinions. Thanks in advance
 
The correct way to neutralize acid is with a base.
I'm no chemist but I believe that oil doesn't have a Ph so no oil will neutralize an acid.
Whenever I have a treatment that uses acid, I neutralize it with a baking soda bath and then water and then dry it immediately.
Water doesn't rust metal instantaneously but if you're really worried about it, wash the part with oil after washing it with water. A little heat will help.
As for removing rust on a non critical area, I'd use Evaporust as it doesn't eat the metal. It's also water based but I've never experienced rust on a part after washing it and drying it.
 
Inferno said:
The correct way to neutralize acid is with a base.
I'm no chemist but I believe that oil doesn't have a Ph so no oil will neutralize an acid.
Whenever I have a treatment that uses acid, I neutralize it with a baking soda bath and then water and then dry it immediately.
Water doesn't rust metal instantaneously but if you're really worried about it, wash the part with oil after washing it with water. A little heat will help.
As for removing rust on a non critical area, I'd use Evaporust as it doesn't eat the metal. It's also water based but I've never experienced rust on a part after washing it and drying it.
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Ok, I follow you. I appreciate the info
 
As far as the baking soda goes, do I just dunk it in the powder or mix it in water?
 
Pevehouse said:
As far as the baking soda goes, do I just dunk it in the powder or mix it in water?
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You are going to wind up using water at some point, and thats OK. Just use hot water and blow it off with compressed air, maybe set it near a heat source for a bit, then oil it.

I would use Evaporust and a hot soapy water cleaning afterwards with a hot water rinse.

I do this frequently with no rust issues, no chemicals needed.
 
RaisedByWolves said:
You are going to wind up using water at some point, and thats OK. Just use hot water and blow it off with compressed air, maybe set it near a heat source for a bit, then oil it.

I would use Evaporust and a hot soapy water cleaning afterwards with a hot water rinse.

I do this frequently with no rust issues, no chemicals needed.
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Ok, that’s what I will do. I have had my experience with flash rusting and figured someone in here would have a better method. Thank you
 
The baking soda would need to be in water. After blowing off the excess water, you could rinse with a solvent that water dissolves in readily, such as alcohol, to endure no trace of water remain, before coating with something oily as a water/vapor protectant.
 
I got some lacquer thinner, that should dry it, right?
 
I am a chemist by training and profession. I would neutralize the acid with a base, Baking soda, washing soda, etc. Rinse with cold water, followed by an immediate dry with towels and warm air. Use a heat gun rather than a torch since the water in the combustion products from a torch will condense on the steel. There is also a possibility of altering any heat treatment if a torch is used. Then application of a light protective coating of oil should keep the steel rust free until assembly.

Non polar solvents like lacquer thinner won't be effective at removing oil. However, WD40 is a known water displacement product. I would still wipe dry and dry with warm air prior but it will help to eliminate water in tight corners.
 
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