how to Clean the Pump Assemblies (calcium / corrosion build up)

[CrankyGypsy]

UPDATE: i've been doing some research and found that a sulfamic acid solution (rather than granulated, which is the MSDS i had originally found) can be harmful to aluminum unless it is combined with an inhibitor. so there is a risk with this process. however, submerging my pump parts for two hours did not yield any negative issues. and aluminum will quickly form a tough aluminum oxide layer over any of its damaged surface. from my tests, it seems using sulfamic acid on heavily salt-damaged areas causes pitting of the aluminum. salt water "breaks down" aluminum over long periods (basically softening it). salt doesn't dissolve it - it will appear intact, but with a slightly darker discoloration. when left in the acid overnight, it can soften further and even eat away at these weakened areas like tooth decay. however, this only affects areas that salt deposits are allowed to sit for long periods. things like my pump that are rinsed thoroughly after each use, i would not hesitate to dip again.

i went to Home Depot and picked up some Sulfamic Acid in the tile/flooring cleaning section for $6. i dissolved the entire container (1LB/454gm) in 1.5 gallons of hot tap water (about an 8% solution i believe). as a test, i left my damaged impeller housing soaking for an hour. upon returning, there was a bit of foaming on the surface of the water, so i knew something had happened. once out, i used an old toothbrush rather quickly on all the surfaces with a little extra time on the areas of thicker build-up. i then rinsed it and allowed it to dry. the bottom half (submerged half) is corrosion free and the dryer it gets, the brighter it looks. some areas around the joining surfaces were very thick/hard with scale and this still removed most of it. i'm sure letting it soak additional time will loosen the tiny remainder of it up. no harm whatsoever seems to have come of the aluminum housing or steel wear ring.

i'm considering also soaking the duct housing assembly containing the bearings since the acid does not appear to be harmful to rubber (Salt Away contains Sulfamic Acid).

maintenance-wise, i plan to add the bar zinc anode my pumps don't have and occasionally spray a film of Boeshield T9 on the assemblies to keep them clean.


i've read of boaters using vinegar to break-up calcium deposits (even inside the engine). my attempts at this were very unsatisfactory on the pump exteriors, so i have doubts at it doing any good inside the engine ...especially at the meager 9% concentration the general public has easy access to. Note: vinegar will also eat at aluminum.
to clean the inside of the engine, i would use Salt Away's recommendations and run the engine on plain water for five minutes to ensure the thermostat is open. then switch to the Salt Away for at least 10 seconds or until you see it expelling from the pumps. shut the water/SA solution down and immediately turn off the engine (a helper would probably ensure more Salt Away remains in the engine). allow to soak internally for 24hrs. repeat the process over a few days to break-up and expel the gunk. also, Salt Away does not recommend rinsing with plain water after a flush as it continues to work and leaves a protective coating.

 

[Julian]

You knew someone had to ask this.....Where are the photos???

 

[CrankyGypsy]

top half: attempted to clean by soaking in 9% vinegar; brushing with vinegar; brushing with Bar Keeper's Friend; brushing with CLR.

bottom half: soaked in 8% Sulfamic Acid for 60 mins.

 

[Julian]

Do you need a special bucket for Sulfamic Acid?

 

[rkluck]

Interesting. I may try this.

 

[CrankyGypsy]

i mixed it in one of those large buckets that plaster for drywall comes in. doesn't seem to be doing anything to it.

i also checked the MSDS.
seems to be harmful to organic materials only. rubber gloves, eye protection, a mask, and synthetic apron recommended. inhalation of the dry chemical would be hazardous on mucous membranes and especially the lungs. the stuff i bought is granulated rather that fine, so i don't see this as a huge danger. wash hands with soap after handling. i neutralized the part with soap and copious amounts of water.

it is disposable down the drain at lower concentrations. just to be that much safer, i'd dilute it further (3 gallons = 4%) and flush the drain a while.

 

[CrankyGypsy]

with the test out of the way, i tried it on my SBT housing that was really gnarly:


this is after 2 hours of soaking:

 

[Julian]

Wow....gotta get me some of that stuff!!!!

 

[CrankyGypsy]

this has got me thinking. i have used Dawn in a pinch when i've run out of Salt Away before getting to the store. but there is no way any amount of Dawn is going to remove this build-up ...ever.