Citric Acid - Fail

[David Peterson]

Now I know why they call it citric ACID...

Too long in citric acid and metal gets eaten away. In the process of restoring this Stanley, I forgot to take the plane bed out of its citric bath overnight. When I took it out the next morning, after about a 20 hour soak, the previously smooth sides were turned a dull grey and pockmarked throughout. I didn't imagine the stuff would be so corrosive. Maybe my concentration was too high. Either way,,,Duh!

So now I have this poor Bedrock 5 1/2. It lasted 100 years in pretty fair shape - and then I got my hands on it. The sole wasn't damaged so it's still a user but a far cry from the refurbishment I had in mind. Live and learn.


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[Steve Voigt]

Dave,
I kind of doubt the citric acid caused the pitting in the sides. More likely, the pits were already there, but covered by a film of corrosion that obscured them.
The plane doesn't look bad at all. If you want the sides to be flat, stick some 3x paper to a flat surface and sand, starting around 100 grit and working up. If the pits don't all come out, you can use a buffing wheel after.

[Joe Tilson]

It is my understanding we should use 1 cup citric acid per 1 gal. of water. I have not had any problems with citric acid even leaving it over night. The pits could have been there, but not seen. I ran into that with a #4 sweetheart I found a few weeks ago. I like it because it does not remove the Japanning.

[Prashun Patel]

While i dont advise it, i have soaked planes and blades in citric acid highly concentrated and forgotten about them until a day later. I dont believe it causes pitting as quickly as you mit think. I like to take my soakers to a fine wire cup wheel after drying. You might just be in need of a good buffing.

[Ray Bohn]

I agree with the comments regarding the pitting for two reasons. Logically, an acid would remove equal amounts of metal from the surface, like the drag racing outlaws did back in the day to reduce weight; you had to make sure the inspectors didn't lean on your fenders or they would bend faster than today's fenders. The second reason - Due to laziness and lack of knowledge, I left a plane blade in citric acid for several days. It reduced the the thickness of the metals equally across the surface, except where there was some heavy rust.

[David Peterson]

Interesting to hear. I hadn't thought that the stuff was THAT caustic. When it went in the exterior sides seemed to be in good shape. You wouldn't have know that there was pitting hiding underneath from the look of things. But when I took it out of the bath, the sides had gone black and sanding it just brought out the rough finish that's there now. I'd assumed it was the citric acid that did the damage. Your thoughts would explain why the sole came out clean and unscathed.
Nothing to lose now so I'll keep at it. Thanks for the advice.

[Mike Holbrook]

Highland Woodworking carries rolls of high quality sand paper that can be stuck to any flat surface for leveling plane bodies. I use my table saw table, so I at least get some work out of it.

[Jacob Reverb]

I would hit it with a base (ammonia) after you're done with the acid to try to neutralize any citric acid remaining in the pits. If you don't, I suspect corrosion might come back fast. (Won't citric acid dry out to a solid in the absence of water and won't it be hydrophilic like salt?)

[don wilwol]

I don't use anywhere near 1 cup to a gallon, but I often throw a rusty plane in the solution before work on Sunday night and leave it until Friday. I've never had it hurt.

[Joe Tilson]

After cleaning with citric acid, the instructions say to clean with water and use a brush while doing so. It is also good to use a hair dryer to get the moisture off of it. this will prevent flash rusting. Apply a light coat of light weight oil such as WD-40 when dry.
Don, How much critic acid do you use per gallon? I really haven't tried any less.

[don wilwol]

How much critic acid do you use per gallon? I really haven't tried any less.

I never measured it, but I grab a pinch or 2. I bought a 1 pound bag to try it and 've probably de-rusted 25 planes and I'm about half way through the bag. If I had to guess, I'd say about a quarter of what you use. But, I will say, the more you use, the faster it works.

[peter gagliardi]

Like others have said, some sandpaper on something very flat- jointer table say, and just keep rubbing. That is very, very minor, it will come out quickly! Go thru the grits up to about 4-600 it will be fine.
Oh ya, citric acid Can and will do that!
That is probably 1/2 hour to an hour job, good as new!

[Joe Tilson]

As a matter of fact, the fellow doing the demo did say a couple of hours, But I have left them over night with no problem. This got me in the mood to go clean some planes!!!!

[David Peterson]

This is all encouraging. In the past I've always used electrolysis for de-rusting. This was my first stab using Citric Acid and after seeing the result I was ready to pack it in. Now that I've read all the comments I won't give up on the process. Does it always leave the metal so flat and dull? Or is it just a case of buffing it back to shape? I haven't gotten back to the plane yet but I'll have a go this weekend.

[Brett Bobo]

+1 to what Prashun suggested of taking the parts to a brass wire wheel, preferably mounted on the grinder. My preferred method is generally an overnight soak in distilled vinegar, followed by an immediate cleaning using soap and water, dried, and wiped down with a penetrating oil thoroughly. The results with vinegar are likely identical and the results can be alarming with the the flat, blackish, and dull finish you're seeing--I thought it was bound for the trash on my first attempt. Again, save yourself the time and energy if you can do the initial cleaning using a brass wire wheel on the grinder. This is particularly helpful if you soaked all of the plane parts since getting in all of the nooks and crannies of smaller parts with sandpaper is difficult. Then, use the sandpaper to flatten and/or polish the parts to your liking.