Passivation Acids..

[BioFarmer93]

Well, I have Ascetic acid, Boric acid, Muriatic acid and Sulfuric acid sitting around the house... Does anyone know if any of these are OK for passivating plates? I don't seem to be having any luck finding Citric acid locally, and I don't want to order it if I don't have to...

[myoldyourgold]

Bio, there must be a beer / wine supplier for home brewers around you some where. You can buy citric acid by the pound form them. If not pm me and I will send you some.

[Jedomi]

Wouldn't Limes give you that?... and whats this process you are doing? I have a Lime tree in my yard, should i do it to my plates too?

[nst6563]

Limes contain citric acid, as do all citric based fruits...but they also contain a lot of other things like sugars (dextrose/sucrose/whatever it's called) and some oils I think (oh, and that tangy natural flavor ). In cooking if you don't have citric acid, I've seen people recommend substituting with lemon juice. For passivating metals, I would recommend to get the most pure you can get.

Pure Citric acid isn't very expensive, and like myoldyourgold mentioned...wine/beer making supply shops should have it. I picked up 4lbs a couple weeks ago and paid $8. Well worth the money to do it right.

One thing to note - and this may be common sense - but wear rubber gloves when handling the plates. The oil from your hands can contaminate them and could mess up your passivation.

[BioFarmer93]

Yes, there is a beer & wine making supply place here, I'll run over there at lunch tomorrow and check them out.. And thank you for the tip about where it might be found locally..
BUT- other than the dangers of increased strength of the other acids I mentioned, does anyone know why only citric acid is used for passivation? Didn't I read somewhere that dilute sulfuric could be used also, or is my mind just playing tricks on me?

[nst6563]

I'm not sure exactly why citric is used other than it's "environmentally friendly", easier to handle, less precautions, etc...and of course if you really wanted to, you could eat it.

Nitric Acid was and still is used quite commonly, there are just more hazards in dealing with it. Although, my understanding of stainless steel passivation methods is that the Nitric Acid based bath passivates and oxidates at the same time. Citric Acid needs two steps: 1 being the acid bath, 2 being the oxidation.
I've also come across numerous documents on the different methods of oxidation and them into a liquid oxidizing agent.their effectiveness. Pure O2 is the easiest/cheapest method and is also very effective. The other methods include rinsing the plates of the citric acid bath and then submersing

I've been experimenting with bathing the plates in a liquid oxidizing agent such as Peroxide. It's too early to tell what effect it has on the HHO application, but the industry documentation available through google shows that a liquid oxidizing agent results in superior surface oxide layers which offer better corrosion protection. This COULD also mean that it makes the plates more resistive. Further testing will tell.

[myoldyourgold]

I'm not sure exactly why citric is used other than it's "environmentally friendly", easier to handle, less precautions, etc...and of course if you really wanted to, you could eat it.

The only reason it is used, is it is environmentally friendly!! Nitric acid which is also available at the beer & wine making store is just as good just requires proper handling and disposal.

[BioFarmer93]

-thank you, gentlemen..

[BioFarmer93]

-Picked up 2 lbs. of citric acid @ $4.50 lb. at the local beer & wine making supply house today. The build slowly continues.........