Question for the Chemists out there

[Bob S]

Just bought a lb of citric acid powder (thank you Ross) and will be mixing it with distilled water @ between 4-10% by weight for cleaning and rust removal. I want to thicken it up or make a gel to use on my stuffing box and prop. I want it to stick and slow the drying process. I was thinking Glycerin or maybe Xantham Gum. Any suggestions?

 

[Ross]

cook some corn starch in it.

 

[Bob S]

Ross,
Have you done that before (corn starch)? Just curious how big a batch do you make up at a time? I figured a 1/2# citric acid to a gal of distilled water. Can I store it?

 

[Chris Burti]

Why bother??? Oxalic acid is a far stronger organic acid, comes prepared inexpensively in Zud and Barkeeper's Friend and if used as a paste with a bronze/brass wire brush will make those parts look like new in a short time with little effort.

 

[Bob S]

Chris,

I agree but I think the citric acid is better for stainless steel use. I've been reading a lot on the subject, mostly from a metal finishing forum:
http://www.finishing.com/Home/about.html
There's a lot of info and discussions about the process of passivation.
http://www.finishing.com/286/80.shtml
http://www.finishing.com/466/18.shtml

There has been many discussions here about different methods of removing rust, tarnish and barnacles. I remember reading Ross's and RichH's recommendations and felt I would try experimenting. I'm not spending lots of money as a # of citric acid powder is not expensive. I have used Barkeepers but I think there is a pumice in it that can micro scratch stainless.

 

[finding41]

I got 100g of the stuff to remove the stains on my hull bottom. It is hard to find around here. I had to order it a week in advance from the specialty pharmacy.

 

[Steve Dion]

Bob:

You may want to try Oxalic acid like Chris mentioned. It is cheap too.

http://www.ebay.com/itm/OXALIC-ACID...924?pt=LH_DefaultDomain_0&hash=item4ab803f0e4

For your Stainless Steel Cleaning, here is the product.

http://www.spotlessstainless.com/howitworks.html

 

[Ross]

Just mix it as you need it. Citric acid stores perfectly well dry. A tablespoonful of corn starch and a cup of water will make a rather thick jell then you can blend in a couple of spoonfuls of acid crystals.

 

[shemandr]

I'm not a chemist but why not use navel jelly. Its phosphoric acid - I think. I've used it on aluminum and stainless before with good results. I didn't even use gloves but I would today. And eye protection. I don't know about the passivation issue.

 

[Rich Stidger]

Will this citric acid soup clean stainless? I am looking for a home-made recipe that will work as well as SpotlessStainless. SpotlessStainless works quite well but is rather pricey at $30/qt (plus shipping unless buying in quantity). You basically brush it on, wait 30 minutes and rinse off with fresh water. Need to have temps upward of 70 degrees for good results.