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Lemon juice

Jun 19, 2004
360
Morgan M28 O/I Ocean Gate, NJ
OK folks... I gotta throw a -rusty- wrench in the works here... our Morgan 28 has chain plates strapped to the hull exterior. Over the years she has developed rust stains that run down the hull from each one. Nothing I've tried so far has worked.
So far I see that lemon juice, etc. works for tannin but what about rust?
 
May 12, 2004
1,260
Hunter Cherubini 30 New Port Richey
Not to hi-jack the thread but, Jim, have you thoroughly inspected your chainplates? I had one that was weeping some rust but otherwise looked fine. Turns out it was deteriorating from the inside...badly. Didn't know until it snapped while under sail. Just my $.02.
 
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Jun 19, 2004
360
Morgan M28 O/I Ocean Gate, NJ
Thanks for this Roland! Yes so far they're OK but they're on the schedule for replacement
 
Mar 26, 2011
2,667
Corsair F-24 MK I Deale, MD
The only time I have worried over the stain was when I extended the transoms and needed to get a good color match. I then let the stain come back. As far As I'm concerned, worrying over the mustache is like washing the bottoms of your shoes. That said, I used very dilute CLR (probably less than $1 worth) in a spray bottle. Worked fast.

1. Acids do not just very in pKA and pH, they also vary in their relative aggressiveness towards metals. For example, for a given amount of scale removal, vinegar will cause more metal damage than anything else. I didn't test lemon juice, but I would expected it to me more like CLR (lactic acid). For iron, phosphoric or HCl (properly diluted) will do the least damage. For aluminum, CLR is probably the best. Thus, the best choice depends on the metals at risk. I recently did some tests for a magazine.
2. Gels just increase contact time. Soaking a rag the solution and leaving it there does the same thing. MSDS/SDS data will tell you which acid they use.
 
Jun 21, 2007
2,093
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Several years ago, Mainesail posted information about a product called Spotless Stainless. Earned high marks. It is a gel whose primary ingredient is citric acid. It will remove the surface rust stains from stainless steel. It is advertised that citric acid also will passify the surface so that the surface surface takes longer to reappear. This has been my result. I apply once per year to my 36 year old exterior stainless and it looks quite good again. SpotlessStainless also will remove SS rust leach stains from gelcoat. Attached are pictures of one of my before and after Spotless Stainless locations. A PO had mounted something on the stern pulpit and underneath, not able to have normal oxygenation, it became pitted. Normal polishing wouldn't remove the rust from the pitted spots. Took a couple of applications of SpotlessStainless to restore to a much less embarrassing state. Google SpotlessStainless for the website. A similar product, but not quite as effective, is CitriSurf.
 

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Ward H

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Nov 7, 2011
2,720
Catalina 30 Mk II Barnegat, NJ
I've also used Spotless Stainless after reading Mainsail's post about it. I had the same great results that Rardi shows. I use it now for all my stainless bits. Tried something else on the railings and they quickly showed surface rust again while the first bits I used Spotless Stainless on are still free of rust.
 
Jun 19, 2004
360
Morgan M28 O/I Ocean Gate, NJ
+1 on the Spotless Stainless! We also tried many different products over the years, but no joy. Our stanchions looked similar to yours until we began using this product.
I didn't think to try it on the rust stains on the hull; gonna give that a try once spring arrives...
 
Jan 19, 2010
8,836
Hunter 26 Charleston
I use a paste of baking soda (weak acid) to rub in and scrub/rinse with vinegar then water.
@Worldwalker88
Baking soda in water [NaHCO3] is a base.

In water the sodium atom dissociates leaving bicarbonate... the bicarbonate plucks a proton off of water leaving hydroxide.... (definition of an Arrhenius base)
1) NaHCO3(aq) --> [Na]+ + [HCO3]-
2) [HCO3]- + H2O --> H2CO3 + OH-


Vinegar is a 5% solution of acetic acid. The acetic acid protonates the bicarbonate accelerating the production of carbonic acid... which dissociates into CO2 and H2O...which leads to a lot of CO2 bubbles (think science fair volcano experiment).

H2CO3 --> H2O + CO2
 

Kermit

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Jul 31, 2010
5,481
AquaCat 12.5 17342 Wateree Lake, SC
@Worldwalker88
Baking soda in water [NaHCO3] is a base.

In water the sodium atom dissociates leaving bicarbonate... the bicarbonate plucks a proton off of water leaving hydroxide.... (definition of an Arrhenius base)
1) NaHCO3(aq) --> [Na]+ + [HCO3]-
2) [HCO3]- + H2O --> H2CO3 + OH-


Vinegar is a 5% solution of acetic acid. The acetic acid protonates the bicarbonate accelerating the production of carbonic acid... which dissociates into CO2 and H2O...which leads to a lot of CO2 bubbles (think science fair volcano experiment).

H2CO3 --> H2O + CO2
So, is this a good thing, a bad thing or just you showing off?
(Sorry. You know I love you, Man.)
 
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Oct 22, 2014
13,136
CAL 35 Cruiser moored EVERETT WA
Thank you RG. Brought back memories of chemistry 101 and the mind numbing gorgeous red head that sat 2 rows up and 1 to the side. Man she had great looking legs.
 

SFS

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Aug 18, 2015
1,818
Hunter 31 Tampa Bay
Brought back some memories for me too, but they weren't as pleasant as a red head with great legs. Lewis adducts, pKa values, the whole 8.2296 meters. Nice to see name Arrhenius again though.
 

SFS

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Aug 18, 2015
1,818
Hunter 31 Tampa Bay
I can't think of a single time I giggled in class - way too many chemistry and physics classes. I've tried to make up for it since though, so it's not a 2017 thing.
 
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Oct 22, 2014
13,136
CAL 35 Cruiser moored EVERETT WA
Gave me a solid foundation. Reached the conclusion that a career in GeoChem - what I thought I wanted as a HS senior, would have me on the NorthSlope. I liked the Colorado skiing and the afterhour events. So took the knowledge and found a different path. CSM is a great school.
 
Oct 22, 2014
13,136
CAL 35 Cruiser moored EVERETT WA
The Chem analysis post explained the reason for bubbles when mixing acid with baking soda. Baking Soda can be a non toxic cleaner on your boat but needs to be nutralized after scrubing. A couple of us had chemistry classes and recognized the Nobel winners name. And I had a crush on a red head. It really is pretty simple when you think about it.

Oh and Happy New Year. Lemon Juice and Rum