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Cleaning Corrosion - good idea?

If this isn't seen as directly steam related, I can post in another forum.
https://forum.heatinghelp.com/discussion/182417/time-for-a-new-radiator
Dunkirk P4B - no idea install date but I bought the house in 2009.
A while back, I posted photos and got excellent feedback above.
Today, I was cleaning up and noticed a lot of corrosion on the back of the boiler (near the return) See photo.

Few questions.
1) Any idea how long do I have? Despite how it looks, underneath is currently dry.
2) Can I clean this with a wire brush or similar? Or, it way too late and would this likely create a massive issue?
3) Time for a new furnace or can a plumber actually repair this?
Thank you.
https://forum.heatinghelp.com/discussion/182417/time-for-a-new-radiator
Dunkirk P4B - no idea install date but I bought the house in 2009.
A while back, I posted photos and got excellent feedback above.
Today, I was cleaning up and noticed a lot of corrosion on the back of the boiler (near the return) See photo.

Few questions.
1) Any idea how long do I have? Despite how it looks, underneath is currently dry.
2) Can I clean this with a wire brush or similar? Or, it way too late and would this likely create a massive issue?
3) Time for a new furnace or can a plumber actually repair this?
Thank you.
0
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Comments
I wouldn't touch it unless it was to fix the pipe. It could hold for a day, it could hold for 2 years, can't really predict it.
A professional should be able to fix that, how expensive and how long it takes depends on how hard it is to get out. Seeing the copper indicates to me it shouldn't be too hateful of a job.
EcoSteam ES-20 Advanced Boiler Control
Boiler pictures updated 2/21/15
https://www.facebook.com/media/set/?set=a.10202744301871904.1073741828.1330391881&type=1&l=c34ad6ee78
Definitely get someone to come out and look at it. As @KC_Jones said, hard to predict how long it will hold. Better to have a plan to deal with it than have it be an emergency call.
18 Ounce per Square Inch Gauge
Time Delay Relay in Series with Thermostat
Operating Pressure 0.3-0.5 Ounce per Square Inch
Why don't I ever follow my own advice?
I now look at the manual feed valve as a slow poison and avoid unless absolutely necessary.
https://iopscience.iop.org/article/10.1149/1.2428681/pdf
(as an aside, i said "theoretical" because actual deionized water would start ripping ions off of those metals the second it came into contact with them. it is the ions that carry charge through an electrolyte, so it makes sense that deionized water can carry much less current. i suspect this is why the accepted wisdom leans towards pH over 8, cause if you were trying to drive the pH down much lower the water would just end up leaching ions right from the metal)
so with the electric circuit analogy, the current in the circuit represents the rate of corrosion, since the movement of ions (anions and cations) to and from the anode and cathode (the dissimilar metals) is both what constitutes the movement of charge (electrical current) and the displacement of material from one metal to the other.
so bringing it all together, different metal pairings have different voltage drops between them driving the reaction, but more electrolytic the boiler water is (i.e. the more alkaline it is from having more electrolytes dissolved in it), the lower its resistance to current flowing across that voltage drop, and the more galvanic corrosion you will have.
but I am very ignorant of how galvanic corrosion works so maybe there's a simple explanation
Thanks for the quick reply
as to your second point, galvanic corrosion has a one-way transfer of material from the metal that's the most anodic to the metal that's the most cathodic, leaving every other metal in the "circuit" untouched. so if this were GC between the steel and the copper piping, the steel would be the cathode, the copper would be the anode, the iron fitting would be untouched, there'd be a flow of electrons through the pipes themselves from the copper to the steel, and there'd also be a flow of copper ions through the boiler water that would then land on and attach to the steel. so like in the figure in this link shows, the material is all leaving the anode and accumulating on the cathode (https://www.solaracks.com/wp-content/uploads/galvanic-corrosion-explained-1024x654.jpg).
BUT! actually your question raises more questions for me and i'm about at the limit of what i know, but i will put my new theory in the next post cause it explains something i should've noticed before but didn't. so thank you for that.
so that aluminum jacket that surrounds the boiler is actually going to be in electrical contact with that steel nipple, since both are going to be attached to the boiler structure. so we've got (1) two dissimilar metals (and aluminum alloys are very anodic, they love to give up ions of whatever metal they were alloyed with, and (2) those metals are in electrical contact. and then (3) along comes a leak that comes into contact with both the metals, along with a localized region of high humidity around the steel and aluminum, where humid air can also serve as the electrolyte in GC. so the GC electric circuit is leaching ions from really anywhere on that aluminum jacket and depositing them on the steel nipple and fittings. the aluminum jacket is so big (in terms of surface area) that you don't even really see any material that's been removed (and it would all be on the unpainted side), but that material has definitely visibly accumulated on the steel.
so that's my final guess. i could be totally wrong. like i said, i'm no plumber, or any kind of expert on corrosion. but if this is what's happening, first i'd check to see that the aluminum jacket isn't directly contacting any of that steel or accumulated gunk (they'd still be electrically connected, but instead of a direct path the circuit would have to wind through the entire pathway through the housing, and would have much greater resistance). then i'd check the humidity in the basement and try to bring that down.
And whatever you do, don't touch it until your ready