Thanks, hopefully this may save me the effort of having to find a place that will hot tank them, no one does anymore because of the high cost of disposing of the chemicals.

 

ok, its in, i am curious to know what happens as well
it should not cause any issues with the mating surface unless the surfaces is already damaged by rust, that is if there is anything more than surface rust on the mating surface

but one thing that comes to mind that i wouldnt worry too much about is hydrogen emmbrittlement, this is where iron becomes brittle in the presence of excess hydrogen...duh
anyway this can be avoided by closely monitoring the amount of washing soda used,and or having the water constantly circulating, washing soda being only a catalyst in this process can hypothetically be cut out completely, but it would quadrouple the time it would take to do the same work

another method you may consider using is a caustic lye solution,
lye is fairly dangerous to work with but if you are really trying to save money it might not be such a bad idea.
to clean with lye you can use a steel container like a 55 gallon drum and heat it slightly to remove rust, or use a plastic container that you cannot heat but it wil only about 3/4 as effective
fill tub with water and slowly add 3 ounces of lye per gallon to the water, never water to lye
then wearing caustic proof gloves, and goggles, dip your part (no aluminum, bearings, plastics, etc) and leave it sit for a good couple of hours.
if you do decide to do this and you do happen to get lye on you, do not put water on it, pour vinegar or another acid to neutralize it, lye is very basic and will take an acid to stop the reaction to skin.

 

I remember during my research for the aforementioned science fair project, my chemical-engineer parents and I decided on vinegar to add to the water. Also of note, if you reverse the polarity of the circuit, i.e. negative to your part, positive to the other piece of metal... and use a rod or plate of some desirable material (steel, brass, cadmium) you could, very effectively, chrome, cad-plate, or create a mirrored surface in almost any conceivable metal part (chrome wheels come to mind). This is the same process that is used commercially, known as anodizing. Commercial users also have a bunch of fun additives and processes where they can turn the coating black, blue, red, purple, or whatever.

Am searching for a 55-100 gal fishtank as I type

 

well im sure youve tried craigslist but i checked Chicago for ya
heres a few
http://chicago.craigslist.org/nch/for/984870025.html
http://chicago.craigslist.org/chc/for/984485236.html

 

I read on anodizing/electrolysis many years ago but am no longer acquainted with the specifics any longer. But caution is warranted. There are many readers of this forum that have not had basic chemistry and would be inclined to dabble with this lab experiment without proper supervision or education. This is where Darwin Awards are made.

One of the things I do remember is that certain experiments can result in the liberation of air-borne compounds that are very unhealthy to breathe and caustic water-miscible solutions that are toxic. Many of the compounds created can be combustible and/or toxic if inhaled, touched by skin or other mucous membranes.

I would just exercise caution if you wish to dabble with anodizing - make sure you know what you are doing and have taken the proper safety precautions. Not to be a Frightened Nellie but the old-timers I respect all make safety and knowledge of a process job 1.

The past Mustang Monthly magazine editorial sounds a similar note of caution in his eulogy to a friend.

 

OK Head's all done
water was up to half the cylinder head, so i could show before and after
1.5 table spoon baking soda per gallon
12v @ 10 amps, for 16 hours
then rinsed with HOT water and dryed with air




Mating Surfaces are like new, and it removed 99% of the carbon build up.
i will be doing this for every part i want rust off of and sanding or blasting is out of the question

 

Thanks for the links Joe, and KICKA$$ job on the heads... now I know how I'm going to get mine clean for the upcoming motor swap

 

your car's a sixxer?

 

nope v8,
thats a head from a 242 amc jeep
it was at my house when we moved in, and apaprently they are worth something so i hung on to it, and in a rush i left it in the parts washer for a summer and condensation got the best of it

 

ohh, yeah i thought it was a v8....