Stormin' Norman wrote:
On Thu, 13 Jul 2017 20:18:54 -0400, Ed Pawlowski wrote:

On 7/13/2017 7:22 PM, Stormin' Norman wrote:
Does anyone have first hand, personal experience removing and
neutralizing corrosion on cast aluminum?

I was given a never used, 3 year old pressure washer, 3k psi, 190cc
(6hp) Honda engine. The unit was stored in a garage that was about
200 yards from the pacific ocean.

The owner could not crank the engine and didn't want to be bothered
with it. Upon examination I discovered a fair amount of surface
corrosion on the flywheel and some of the cooling fins on the
crankcase and cylinder housing.

After knocking off the corrosion from the flywheel, removing the spark
plug and inspecting the cylinder I am able to easily crank the engine
by hand.

I would like to completely remove all the corrosion and neutralize it.
I remember the air crews using soft wire wheels, phosphoric acid,
detergent and lots of clean water to deal with some aircraft
corrosion.

Does anyone have first hand experience dealing with this kind of
issue? If so, would you please share your knowledge?


The corrosion is actually oxidation. Depending on the severity you can
use SOS pads, vinegar, sodium hydroxide. Loctite makes a jelly you put
on and wash off. I've not used it but I saw the results a friend used
and it was ok.

I have subsequently gotten some more information from the original
owner. Turns out he had the unit stored under a shelf that had some
drain cleaner on it. Apparently the container of drain cleaner
ruptured and dripped on the machine which is what caused the damage /
corrosion. I suppose you could call it oxidation, but that would be
akin to calling stage 4 cancer a minor medical issue.

So, now, I will neutralize the acid with a slurry of baking soda and
thoroughly clean the area.

The sodium hydroxide you mention is basically lye, which is a
component of a lot of drain cleaners, so, I will avoid that. The
Aluminum Jelly, by loctite, is basically phosphoric acid, as I
mentioned above.

Navel jelly is a bit stonger, more effective.

Greg

I think a lot of neutralizing, scrubbing and protecting is the best I
will be able to do. Drain cleaner is nasty stuff.

Sounds like a good job and learning experience for one of the grand
kids.