OP
What is a good source for phosphoric acid?
Can steel cylinders be glass beaded?
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captain
Contributor
There is a product called Ospho made by Skyco that is a phosphoric acid based metal prep solution. It is usually available at Ace or True Value hardware stores or a marine supply stores or marina stores.
OP
captain
Contributor
I have heard of sand being used but never tried it. I fill my own tanks and do my own inspections. I generally only do any tumbing or wipping just before taking them in for hydro. I am not a fanatical as some about light rust. They come back from the hydro shop with flash rust anyway and I don't worry about it.
Aluminum oxide works sweet, look in your area for blasting media.he A-O will clean out any rust. Go to the Global mfg site for the instructions. PP02 hit it right on the head for using glass beads to 02 clean the tank.
Rick Christ
Contributor
captain
Contributor
Ospho is mainly phosphoric acid commonly used to clean steel. It will only leave the black coating if it is not rinsed off and allowed to dry on the rust. It will not leave a black coating on clean steel.
oxyhacker
Guest
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The black layer is iron phosphate. It's an inevitable byproduct of acid cleaning, and a thin layer of it is even protective. If it gets too heavy though it is no longer bonded to the tank wall, and can come loose and cause problems later.
Because of this, Global and others who sell acidic cleaners recommend against using them without tumbling. Also, without the agitation and scouring action of a tumbler or whip, the iron phosphate layer that forms on the rusty areas can actually protect the rust from further action of the acid, so adding a mechanical cleaning action like tumbling or a whip will make it much more effective.
BTW, someone asked about where to get pure phosphoric acid. It's not necessarily desirable. Most of the mixes mentioned, like Global's, Oakite, or Ospho are acid with a bit of a surfactant cleaner to improve the cleaning action, and keep the crud in suspension so the acid can do its work. Just rinse the hell out of the tank afterwards as the surfactant residue can actually be more of a hazard than the acid.
Because of this, Global and others who sell acidic cleaners recommend against using them without tumbling. Also, without the agitation and scouring action of a tumbler or whip, the iron phosphate layer that forms on the rusty areas can actually protect the rust from further action of the acid, so adding a mechanical cleaning action like tumbling or a whip will make it much more effective.
BTW, someone asked about where to get pure phosphoric acid. It's not necessarily desirable. Most of the mixes mentioned, like Global's, Oakite, or Ospho are acid with a bit of a surfactant cleaner to improve the cleaning action, and keep the crud in suspension so the acid can do its work. Just rinse the hell out of the tank afterwards as the surfactant residue can actually be more of a hazard than the acid.
Rick Christ
Contributor
Ospho.com
Home Directions for Use Data Shipping Data Quick Quote Contact us
--------------------------------------------------------------------------------
Data
For Questions Not Answered Here Call Factory Direct at: 216-771-1590
Chemical
OSPHO is a balanced formula of Phosphoric acid, Sodium Dichromate, Surfactants, and Extenders.
Physical Boiling Point 240 degrees F Specific Gravity. 1.22 + .04 Average % Nonvolatile = 37.6% + / -0.5%
Soluble in Water Color. Green Liquid Odor. Typical Acidic
Spills Neutralize with basic material, flush with plenty of water.
Respiratory Use adequate ventilation in confined areas, skin and eye protection should be used.
Fire Data No hazard
Decomposition Products Oxides of phosphorus
Health Hazards Irritant to eyes and mucous membranes. In case of external contact, flush with cool water. If swallowed, give 1 or 2 glasses of water or milk and call physician.
KEEP OUT OF REACH OF CHILDREN
Reactivity Can react with various metals to generate hydrogen gas, which could form an explosive concentration in confined spaces. Use adequate ventilation.
MSDS
Ospho Materials Safety Data Sheet
Ospho
Do not put Ospho in a life support breathing system!!!!!!!! :no
cummings66
Contributor
I don't know much about Ospho, but I do know Phosphoric acid can safely be used in breathing cylinders. You're not leaving it in. The procedure is to use a weak solution which varies according to how much rust you have, then you use HOT water to rinse it. That will remove all traces of it, and you can use Litmus paper to verify it's all gone. Then you can go down to a 1% to 2% solution to do the final rinse. You won't get the Black coating, that's more if you goof up and don't clean it right.
In case you're not aware, far more toxic chemicals are used to O2 clean breathing gear in Hospitals. Stuff that has far more warnings than the MSDS for Ospho. You're not leaving the chemicals in there, that's the key. It's clean and dry when you're done, no mist to breathe or things like that. It's perfectly safe. It's been done for a very long time in fact in the dive industry.
In case you're not aware, far more toxic chemicals are used to O2 clean breathing gear in Hospitals. Stuff that has far more warnings than the MSDS for Ospho. You're not leaving the chemicals in there, that's the key. It's clean and dry when you're done, no mist to breathe or things like that. It's perfectly safe. It's been done for a very long time in fact in the dive industry.
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