[SEL] Anyone Ever Used Phosphoric Acid to DeRust

[Orrin Iseminger]

Paul, I would feel uneasy about using the phosphoric acid at full strength
in your oil sump.  The acid not only reacts with the rust, it vigorously
goes after the base metal, as well.  Someone else posted a recommended
dilution.  I suggest you use it.   

Yes, a paint store or the paint department of a hardware store should have
Ospho, or a similar product.  It consists of phosphoric acid and "metal
salts."  I don't know the chemical implication of those metal salts, but
they certainly make a big difference.  I've de-rusted with phosphoric acid
without any follow-up passivation.  After a few weeks I had worse rust than
what I started with. 

Regards, 

Orrin

Orrin Iseminger
Colton, Washington, USA
http://users.moscow.com/oiseming/lc_ant_p/index.htm
So many projects.  So little time.   

-----Original Message-----
From: sel-bounces at lists.stationary-engine.com
[mailto:sel-bounces at lists.stationary-engine.com] On Behalf Of Paul Maples
Sent: Friday, November 10, 2006 4:17 AM
To: The SEL email discussion list
Subject: Re: [SEL] Anyone Ever Used Phosphoric Acid to DeRust

Thanks Orrin,

I have (2) quarts of the phosphoric acid (80% strength) and since I have 
them I thought I would go ahead and use them. Would you use the acid at the 
80% strength or reduce it's strength?

Never heard of Ospho or Metal Ready, are these products available at local 
hardware stores like Ace?