Question for the Chemistry Club

[12string]

The distributor on my boat was full of corrosion.  Moisture in a box full of aluminum, copper, stainless, electricity and heat will do that.

Got is all clean except one stainless vent screen.  Tried PB Blaster, Contact cleaner, Acetone, Muriatic acid and a Baking soda solution.  Nothing is doing much good.  What else?

I'm beginning to fear that if my house blows p it won't be because the building inspector has approved my furnace yet

[donkpow]

Vinegar may work if you can submerge the screen. Naval jelly should hold itself vertically. I assume appearance is not an issue.

[12string]

Just now, donkpow said:

Vinegar may work if you can submerge the screen. Naval jelly. I assume appearance is not an issue.

Oh, right, tried vinegar too.  Don't have naval jelly handy, that may be too thick to get in the screen.  Really fine mesh.

Hmmmm.... I wonder, maybe hit it with a propane torch to loosen it up a bit?

[Longjohn]

Better ask Dr. Mickin he was a chemist.

[Longjohn]

Did you use a wire brush?

[Kzoo]

21 minutes ago, 12string said:

Muriatic acid and a Baking soda solution

Nix the baking soda.  Muriatic acid is my go to cleaner.

[Razors Edge]

What happened to good old fashioned Elbow Grease?

[Kzoo]

1 minute ago, Razors Edge said:

What happened to good old fashioned Elbow Grease?

That grease gets on your shirt and then on your pants and then the wife gets upset and then.

Elbow greats is so 1990ish.

 

[Ralphie]

17 minutes ago, Kzoo said:

Nix the baking soda.  Muriatic acid is my go to cleaner.

Are you Heisenberg?

[Parsnip Totin Jack]

Have you tried turning it off and back on?

[Kzoo]

1 hour ago, RalphWaldoMooseworth said:

Are you Heisenberg?

I had to UTG.  So no.  According to Uncle Wiki, Walt (whoever Walt is) was a trained chemist.  My experimentation with muriatic acid has been completely unscientific.  The only facts actually proved is that it will strip the lining off your lungs if you breath the vapors (don't ask me how I proved this one) and if splashed on the front of a stainless steel dish washer and not noticed for at least 12 hours, the woman of the house (also know as WoKzoo in scientific terms), will force the purchase of a new one. 

[jsharr]

This is off of your boat you say?  The correct marine cleaner would be prop wash of course.

[Airehead]

How is it possible @MickinMDnhas not responded to this?

[Longjohn]

14 minutes ago, Airehead said:

How is it possible @MickinMDnhas not responded to this?

Probably still walking the dog.

[maddmaxx]

You could try some WD-40.  It's cheap and you probably already have some.  (you sprayed it on your bike right)

 

Spray it on a rag, wipe it on, let it sit for a bit, wipe it off.  Might work, might not if the corrosion is too deep.

[jsharr]

17 minutes ago, Airehead said:

How is it possible @MickinMDnhas not responded to this?

 

2 minutes ago, Longjohn said:

Probably still walking the dog.

He started responding about an hour ago.   On page 6 of his response 

[donkpow]

4 hours ago, 12string said:

Hmmmm.... I wonder, maybe hit it with a propane torch to loosen it up a bit?

Probably not. Remember, rust is oxidized iron. A torch will burn (oxidize) the surface of the metal. I think the wire brush is the best idea so far. Any chemical method is likely going to require prolonged exposure or repeated applications.

[Further]

How bout, pop the old one out and a new one in.

You're talking about a tiny piece of screen aren't you ?

[Parsnip Totin Jack]

 Coke or Pepsi? Roadrunner would use Dr Pepper but to each their own.

[12string]

17 hours ago, Further said:

How bout, pop the old one out and a new one in.

You're talking about a tiny piece of screen aren't you ?

funny you should say that ....

They aren't supposed to be replaceable.  But one popped out under pressure from the compressor.  Much easier, now I can soak it.

Muriatic acid and baking soda solution make a really neat steamy reaction.  It seems to be helping.  I did get a shipment packed in dry ice, maybe if I throw that in there too......

The screen is too fine for wire brushing, it's a couple of crossed layers.

 

A torch will burn (oxidize) the surface of the metal.

 

This kind of stuff is why I come hear with questions!

 

 

[donkpow]

Phosphoric acid is good for rust.

It's interesting that Polident uses citric acid along with bicarbonate of soda to clean dentures. It "fizzes" too.

[MickinMD]

Have you tried putting pieces of zinc in the box?  Near the submerged propellers on typical boats in the Chesapeake, there are places to screw-in "zincs" that are available at boating stores: they absorb the corrosion that would otherwise occur to the other nearby metals. When the zincs get chewed up and become much smaller, you unscrew them and replace them with new zincs.  Zinc is very high in the "Activity Series of Metals" - close to Al and higher than Fe, Cr, Cu, etc.  Greater "Activity" means greater tendency to react with non-metals.

So, if you tried to react ZnCl2 with Cu, nothing would happen because Zn is higher in activity than Cu, will give up electrons and grab and hold the negative Cl ions (as well as corrosive O, S, etc.) more strongly than Cu . But if you try to react Zn with CuCl2, it will react to make ZnCl2 plus Cu - making Cu pure again.

That's how zincs work around boat motors: they'll grab the corrosion away from other metals.  It may work in your case if the box is damp enough. Aluminum is fairly reactive, but when it reacts with oxygen it forms a colorless Al2O3 thin layer on top that protects the Al underneath so the Al usually doesn't look corroded or get any worse.

Part of the Activity Series: higher up means more active:

[Longjohn]

1 hour ago, MickinMD said:

Have you tried putting pieces of zinc in the box?  Near the submerged propellers on typical boats in the Chesapeake, there are places to screw-in "zincs" that are available at boating stores: they absorb the corrosion that would otherwise occur to the other nearby metals. When the zincs get chewed up and become much smaller, you unscrew them and replace them with new zincs.  Zinc is very high in the "Activity Series of Metals" - close to Al and higher than Fe, Cr, Cu, etc.  Greater "Activity" means greater tendency to react with non-metals.

So, if you tried to react ZnCl2 with Cu, nothing would happen because Zn is higher in activity than Cu, will give up electrons and grab and hold the negative Cl ions (as well as corrosive O, S, etc.) more strongly than Cu . But if you try to react Zn with CuCl2, it will react to make ZnCl2 plus Cu - making Cu pure again.

That's how zincs work around boat motors: they'll grab the corrosion away from other metals.  It may work in your case if the box is damp enough. Aluminum is fairly reactive, but when it reacts with oxygen it forms a colorless Al2O3 thin layer on top that protects the Al underneath so the Al usually doesn't look corroded or get any worse.

Part of the Activity Series: higher up means more active:

 

Yay, Mickin came through with the definitive answer. 

[Airehead]

1 hour ago, Longjohn said:

 

Yay, Mickin came through with the definitive answer. 

I expected nothing less. 

[12string]

20 hours ago, MickinMD said:

Have you tried putting pieces of zinc in the box?  Near the submerged propellers on typical boats in the Chesapeake, there are places to screw-in "zincs" that are available at boating stores: they absorb the corrosion that would otherwise occur to the other nearby metals. When the zincs get chewed up and become much smaller, you unscrew them and replace them with new zincs.  Zinc is very high in the "Activity Series of Metals" - close to Al and higher than Fe, Cr, Cu, etc.  Greater "Activity" means greater tendency to react with non-metals.

So, if you tried to react ZnCl2 with Cu, nothing would happen because Zn is higher in activity than Cu, will give up electrons and grab and hold the negative Cl ions (as well as corrosive O, S, etc.) more strongly than Cu . But if you try to react Zn with CuCl2, it will react to make ZnCl2 plus Cu - making Cu pure again.

That's how zincs work around boat motors: they'll grab the corrosion away from other metals.  It may work in your case if the box is damp enough. Aluminum is fairly reactive, but when it reacts with oxygen it forms a colorless Al2O3 thin layer on top that protects the Al underneath so the Al usually doesn't look corroded or get any worse.

Part of the Activity Series: higher up means more active:

There's sacrificial zinc  plates all over the outdrive and engine.  This is the inside of the distributor, which is supposed to stay dry thanks to the vents.  I'm trying to clean the vents.

[Razors Edge]

2 minutes ago, 12string said:

There's sacrificial zinc  plates all over the outdrive and engine.  This is the inside of the distributor, which is supposed to stay dry thanks to the vents.  I'm trying to clean the vents.

Have you tried zinc vents?  B-O-O-M!

[Mr. Silly]

On 2/4/2020 at 9:02 PM, Old#7 said:

 Coke or Pepsi? Roadrunner would use Dr Pepper but to each their own.

Dr. Pepper only works at 10, 2 and 4:00.

[Mr. Silly]

How much would a new screen cost?

[maddmaxx]

On 2/5/2020 at 6:43 PM, MickinMD said:

Have you tried putting pieces of zinc in the box?  Near the submerged propellers on typical boats in the Chesapeake, there are places to screw-in "zincs" that are available at boating stores: they absorb the corrosion that would otherwise occur to the other nearby metals. When the zincs get chewed up and become much smaller, you unscrew them and replace them with new zincs.  Zinc is very high in the "Activity Series of Metals" - close to Al and higher than Fe, Cr, Cu, etc.  Greater "Activity" means greater tendency to react with non-metals.

So, if you tried to react ZnCl2 with Cu, nothing would happen because Zn is higher in activity than Cu, will give up electrons and grab and hold the negative Cl ions (as well as corrosive O, S, etc.) more strongly than Cu . But if you try to react Zn with CuCl2, it will react to make ZnCl2 plus Cu - making Cu pure again.

That's how zincs work around boat motors: they'll grab the corrosion away from other metals.  It may work in your case if the box is damp enough. Aluminum is fairly reactive, but when it reacts with oxygen it forms a colorless Al2O3 thin layer on top that protects the Al underneath so the Al usually doesn't look corroded or get any worse.

Part of the Activity Series: higher up means more active:

zincs must be mounted so as to have electrical contact with the protected part.  They serve as the anode in an electrical ckt if they are to be effective.