MP40QD Rusted...

[Larry L]

You didn't mention your cleaning method, but @ca1ore eluded to the issue with vinegar (acetic acid). The issue using this acid is that it hardly dissociates and therefore acts as a neutral compound now able to penetrate the plastic coating. I no longer use vinegar for cleaning magnets. You'd be better off cleaning with muriatic acid (diluted 1 to 10) or citric acid (3/4 - 1 cup made up to one gallon).

Paul - thanks for this info, had not heard this before. Can you explain a little more what you mean by "it hardly dissociates and therefore acts as a neutral compound now able to penetrate the plastic coating"? I always thought an acid was an acid (some stronger than others), and it didn't matter which you used for cleaning.

 

[redfishbluefish]

Acids undergo dissociation in aqueous solution, which is commonly shown as:

HA(aq)+H2O(l)⇌H3O+(aq)+A−(aq)

where HA is the acid. In the case of acetic acid, it very poorly dissociates into acetate and hydrogen, and predominately remains as the "uncharged" acetic acid (HA). (As a comparative, Hydrochloric acid readily dissociated). As a small uncharged compound, it can now penetrate the plastic, and eventual get to the magnet and cause it to rust and swell. It's happened to me, three times over, with the wetsides of MP40's. I can't take credit for "discovering" this....it was Randy Holmes Farley that originally enlightened me to the acetic acid thing. Here's what he said:

I think the effect on plastic may be worse with vinegar than muriatic acid but it may depend on the plastic.

Vinegar can be in the form of acetic acid and that neutral molecule can enter plastic. Diluted muriatic acid won't have any neutral acidic molecules in it to enter plastic, so just exposes the outermost leading edge of plastic. So while the muriatic acid after dilution is a much stronger acid, i would not assume it is worse on plastics.

FWIW, I've used diluted muriatic acid for decades as have others, and I've not heard of cords being damaged, but I've also not inspected them closely.


Ever since I saw this, and my experience with regularly cleaning with vinegar, and the loss of three wetsides, I've stopped using vinegar on any and all magnets.

 

[Larry L]

@redfishbluefish Wow, thanks very much for that info! My (totally serious) suggestion is that you take that entire previous comment and use it to start a new thread with a title in all caps like "DON'T USE VINEGAR TO CLEAN ANYTHING WITH A MAGNET!". It's so common that people do that, and who knows how many expensive pumps have been damaged as a result.

 

[redfishbluefish]

@Larry L , the issue is that it COULD happen, but who knows if it actually happens???? It certainly makes sense! Small neutral compounds could penetrate plastics, but it hasn't been definitively proven. It took a number of years for my magnets to start to swell and fail. My opinion, because is could happen, why take the chance when other things are out there to clean just as well. The other readily available cleaning acids (muriatic and citric) do a good job cleaning, but what I've starting doing is no acid on the magnet portion at all. My magnet portion simply is washed with water and either brushed or scrubbed to remove schmutz off. The "basket" portion, if covered with coraline, is soaked in vinegar overnight, rinsed and put back together.

 

[Larry L]

the issue is that it COULD happen, but who knows if it actually happens?

Sounds like a job for @Bulk Reef Supply investigation!

 

[NAx0]

Finally buy the wet side,

 

[cromag27]

good info @redfishbluefish

i have soaked my octo pods in vinegar solution for weeks (because i forget about them) and it hasn’t visually affected the pods. maybe because i use high quality acrylic instead of abs? maybe it’s because my welded seams are higher quality?

i would also be curious as to test results showing different types of plastics and the effects acetic acid has on them....... not from brs though.

 

[cromag27]

Finally buy the wet side,

i sent you a pm.