white crystal salty looking stuff

[quadster]

Im using a 10 gallon cooler with a sheet of aluminum running down one side ,across the bottom and up the other side. The cathode sheet is forming a salt like substance on both sides out of the solution.Question is Is this normal?Should it be scraped off? Cleaned?Also there is black flake looking things floating and on the bottom? Does it affect the anodizing?
Thanks
Scott

[sswee]

Re: white crystal salty looking stuff

The white substance on the aluminum above the solution is oxidation. It's aluminum's equivalent to rust on steel. You can just wipe it off with a damp rag. The black flake is usually just trash. It normally has no effect on anodizing. SS

[acidrain]

Re: white crystal salty looking stuff

Go with lead sheet if it really bothers you.
Eventually you will lose the connection to the aluminum cathode, but lead will last a really long time.

[neilfj]

Re: white crystal salty looking stuff

Actually, in reality it is a combination both salts and oxidation. The salts grow quickly I'm not sure if they are aluminum salts or sulfuric salts, but they have a definate crystal structure and for me, tend to grow thickest around the connection point to the plates. If it washes off easily, its salts. If it doesn't wash off, its corrosion/oxidation. In either case, you have to clean it off before you use the cathodes again. Both the oxidation and salts will block the conductivity of your cathodes in addition begin to effect the electrical connection, both of which will eventually impact your anodizing.

As mentioned, the quickest way to eliminate this is to replace your aluminum cathode with lead, which require much less cleaning and maintenance. Caswell has anodizing plates available.

[quadster]

Re: white crystal salty looking stuff

Thanks for the great info. Cleaned the alum sheet. Wiped off pretty easy. Also i had four aluminum rivits (i think alum) in the bottom...only one was left? The plastic zip ties that were holding air lines broke also after about the 6th or 7th run....?
Again thanks
Scott

[kmbrly]

Re: white crystal salty looking stuff

What is the acid:water ratio of your electrolyte?

[sswee]

Re: white crystal salty looking stuff

Kimberly
Who are you asking?
SS

[kmbrly]

Re: white crystal salty looking stuff

I was asking Scott because he mentioned that stuff was breaking and disappearing in his tank.

[acidrain]

Re: white crystal salty looking stuff

Some plastics don't do well in the tank...
CPVC gets a oily sticky surface.
Nylon gets brittle and cracks.
Some epoxies get milky and brittle (although there are epoxies specifically made to be acid resistant).
Polypropylene does well, and so does PVC.

[quadster]

Re: white crystal salty looking stuff

Tha ratio is 50/50 battery acid water. Add water when it gets low.They were probably cheap zip ties. Ill do another run this weekend.Everything last weekend came out fine after i cleaned and tightened things up.
Scott

[sswee]

Re: white crystal salty looking stuff

Tha ratio is 50/50 battery acid water. Add water when it gets low.They were probably cheap zip ties. Ill do another run this weekend.Everything last weekend came out fine after i cleaned and tightened things up.
Scott

What CD are you using? If your using the LCD method, your acid is way too hot. Your at about a 17% acid concentration instead of 5%. It's no surprise if your having problems with oxidation.
SS

[mcaswell]

Re: white crystal salty looking stuff

Acidrain mentioned special chemical resistant epoxies. The are of the Phenol Novolac type. Our Caswell GAS TANK SEALER is one!