[SEL] Anyone Ever Used Phosphoric Acid to DeRust

[Orrin Iseminger]

Paul -- 

I've used phosphoric acid to remove light rust.  I use it full strength.
Sometimes I'll neutralize it by putting it into my electrolytic vat.  Other
times I'll not neutralize it, but wash it off, instead, and then apply one
of the metal prep solutions, such as Ospho or Metal Ready.  

For your crankcase, I'd suggest either molasses or a solution of salt and
vinegar.  Just dissolve as much salt as you can in the vinegar and pour the
solution into your crankcase.  It would be cheaper than phosphoric acid and
you probably have already have the supplies you need for the job.   

IMHO, you'll have a slower, more controllable reaction with molasses or
salt/vinegar.  

After de-rusting, I'd passivate the surface with Ospho, or similar.  

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: Thursday, November 09, 2006 4:18 PM
To: The SEL email discussion list
Subject: [SEL] Anyone Ever Used Phosphoric Acid to DeRust

Folks I was wondering if anyone had used phosphoric acid to derust? I have
some phosphoric acid and was thinking of using it in the bottom of my Stover
Block (base) where the oil sump is. Over the years water had condensed in
this area and there is a pretty good rust area for about 2" on the inside of
the crankcase.

If anyone has used Phosphoric Acid I would like to know what strength you
used, did you cut it with water, about how long did you leave it on the
metal and what did you neutralize it with.

Thanks,

Paul