Rhubarb acid

[Kim Malmberg]

I have been experimenting with rhubarb as my rust removing acid. Since rhubarb contains oxalic acid I wanted to try if it would do the same job as citric acid. My experiment is by no means scientific, but the results are good.
According to sources on there web you can make your rhubarb acid by boiling chopped rhubarb with a little water and then bottle the potion. I will probably try that too, but this time I just used about five litres of warm water and then added five or six large stalks of chopped rhubarb.
The rhubarb acid does just what the citric acid does. It might not be an alternative for too many of you, but if you happen to live in a place where rhubarb grows almost wild and commonly, this is a very cheep alternative to citric acid.
It seems you have to use a lot of rhubarb to create a string acid, but aian, in my case that's not a problem.

Some pictures here: https://www.flickr.com/photos/finnberg68/sets/72157645680629802/

[Zach Dillinger]

Interesting... we have a couple of large wild rhubarb patches, so much that we never make use of 10% of it. Might have to try this.

[Kim Malmberg]

That's exactly the same where I live. The rhubarb goes bad for baking or making juice or lemonade from early July so I can use all the old and overgrown rhubarb for rust removal.

[Andre Packwood]

Kim,

Oxalic acid is indeed great as a rust romover, but it is toxic, so I trust you are using great care handling it. As per Wikipedia's article on rhubarb, most of the oxalic acid in found in the leaves; the acidity in the stalks is mostly from malic acid.

Boiling the leaves with soda will produce calcium oxalate that is worse than oxalic acid. My former girlfriend had cut a Dieffenbachia (which contains calcium oxalate) into bits to get rid of it. Her hands were unprotected and the sap caused a rash with a lasting burning sensation on the skin. Washing with water made things worse. We called an emergency poison control center and the only immediate remedy wash to flush the skin with rubbing alcohol.

I think citric acid is a safer alternative. I buy mine at a store where they sell "green" household cleaning products. It is sold in bulk; I paid $7 for a kilogram (2.2 lbs) and it is much cheaper in larger quantities.

Andre

[Judson Green]

IIRC, Bar Keepers Friend has its roots in rhubarb.

http://www.leevalley.com/us/wood/page.aspx?p=69635&cat=1,43415,43439&ap=1

[Kim Malmberg]

Kim,

Oxalic acid is indeed great as a rust romover, but it is toxic, so I trust you are using great care handling it. As per Wikipedia's article on rhubarb, most of the oxalic acid in found in the leaves; the acidity in the stalks is mostly from malic acid.

Boiling the leaves with soda will produce calcium oxalate that is worse than oxalic acid.
Andre

Hi Andre
Thanks for this information. I was never going to add anything else than water to the brew. But are you saying that if I use rhubarb with plain water (boiled or unboiled), I am creating something toxic. If that's the case, I will not use this method for rust removal. What I struggle to understand is how rhubarb leaves (if used) could become environmentally unfriendly, if used as is?

[Moses Yoder]

Lots of plants are either toxic as is or toxic depending on what you do to them. I think all he is saying is be careful it is not available to children or pets. Not sure about proper disposal, perhaps someone can chime in.

[Andre Packwood]

As Moses said. Also, I would wear rubber gloves. A decoction of rhubarb leaves can be used as a natural pesticide in order to rid of aphids on garden plants. I don't think that there is any danger to the environment with the limited quantities involved in your process, just as the leaves are not damaging if left to rot in place. I work for a mining company that uses tons of oxalic acid annually in a metal separation process; they have very strict safety procedures in place.

Andre

[Kim Malmberg]

Thanks for this Andre.
The main reason I have been using citric acid has been based upon my belief that it is a more environmentally friendly alternative than oils or chemicals. So I certainly don't want to use or encourage easy one to use any methods which might be harmful one way or the other.

[george wilson]

Get some "Bar Keeper's Friend" cleanser. It contains oxalic acid. I would use gloves. But,back when I was in school,no one ever told me it was poison,and I used it bare handed to clean my leather work. But perhaps not enough to get me into trouble. I had some in a plastic bag,so I never saw the label.