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Post by freeflow on Mar 6, 2017 22:31:28 GMT
I had some bad calcium deposits built up on my new to me, fresh water 2003 43DS. 3 blade Maxprop feathering prop. I used some white vinegar, lime away, but the real winner was simple, The Works toilet bowl cleaner. this is what I started with...prior to last season. There was a very rough profile with up to 1/8" of lumpy calcium carbonate deposition....this pic doesn't show the poor state it was after another season on Lake Michigan...  anyway, my research came up with some good links and info that explained the process to me.... www.corrosionpedia.com/definition/200/calcareous-coatingDefinition - What does Calcareous Coating mean? A calcareous coating is a layer that consists of calcium carbonate and other salts deposited on the substrate's surface. When the surface is cathodically polarized, as in cathodic protection, this layer is the result of the increased pH adjacent to the protected surface. In other words, it is a layer that contains a mixture of calcium carbonate and magnesium hydroxide deposited on surfaces that are cathodically protected against corrosion, due to the protected surface's increased pH adjustment. The importance of calcareous deposits to the effective, efficient operation of marine cathodic protection systems is generally recognized by engineers and scientists concerned with cathodic protection in submerged marine environments. A calcareous coating is also known as a calcareous deposit." "However, a calcareous deposit also hinders thermal conductivity, which is unwanted in connection to a heat exchanger. Thus, it is important to find a solution in which calcareous deposits do not precipitate on the surface. |
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Post by heatherina on Mar 6, 2017 23:34:44 GMT
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Post by vsergio on Mar 7, 2017 1:25:57 GMT
I hope you realize that the product you used is 15-20% hydrochloric acid (also known as muriatic acid). While dissolving the carbonates you are also chemically etching the prop (HCL dissolves Cu, Zn and Tin).
In simple terms, every time you clean brass (marine Bronze) with HCl the prop will lose weight. Scale deposits in fresh water will not affect the performance of your prop. As far as being an insulator and as such reducing the galvanic protection of the zinc anodes, there is nothing to worry about since the permeability of the scale is sufficient to ensure the anodes are sacrificial.
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Post by freeflow on Mar 7, 2017 13:45:46 GMT
Thank you for the reminder and yes I am very aware of the chemistry. I did a Fresh Water Rinse immediately after applying the works , and vinegar (acetic acid)and getting the calcium loose. I do feel that mechanically there is a huge difference and detriment to having the calcium buildup on the prop micro cavitation, friction losses, and the hinderance of mechanical function of the Feathering will definitely affect the prop performance whether it is fresh or saltwater.
I will be polishing the prop with Brasso after all the calcium is removed. Polishing the prop will also remove some of the bronze ions.
The roughness and profile of the calcium and crusted prop blades was absolutely detrimental to laminar flow around the prop
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Post by freeflow on Mar 9, 2017 20:50:53 GMT
a few more chunks to get off, but the prop feathering works much smoother now...  |
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Post by vsergio on Mar 10, 2017 7:29:30 GMT
Looking at the pics of your prop....sorry... have to say... wow. The bronze shows signs of de-metallization already! Anyway, since its a feathering prop make sure you inject the correct grease in to the movement. This will ensure the blades move proper. If you want to protect your prop against further scale deposits you can apply PropSpeed. Works awesome on feathering props (I have a Variprop , very similar to yours).
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Post by freeflow on Mar 10, 2017 12:47:59 GMT
Yes.....I cleaned the prop to get to the sets screws to insert a zerc to grease it up....with the correct tube of grease as provided by Maxprop.
As far as demetalization. ( is that a word?) Lol. Ok..whatever...it is still metal....some ions are lost when polishing too..don't put too much weight in a poorly lit photo
.also...the scale defensively is adverse to prop performance. ..salt or fresh water irregardless of salinity.
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Post by alenka on Mar 14, 2017 20:52:16 GMT
Freeflow,
Do you happen to know what size prop you have on your 43DS?
I think my Maxprop is a little undersized.
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Post by freeflow on Mar 14, 2017 21:04:59 GMT
Freeflow, Do you happen to know what size prop you have on your 43DS? I think my Maxprop is a little undersized. Hello, I will dig around to see if I can find the model. I do not know the size. I've owned this boat for a short while and I am learning it's components. After cleaning the prop off I learned it is a max prop. I did not see any identifying marks as to model. I will measure it when I return to the boat soon and report back. |
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Post by alenka on Mar 14, 2017 21:12:39 GMT
Thanks
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Post by freeflow on Mar 16, 2017 1:50:55 GMT
here is the size.....?..this is with a Yanmar 4JH-TE  |
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Post by Chris Meyer on Oct 5, 2023 13:03:49 GMT
I had some bad calcium deposits built up on my new to me, fresh water 2003 43DS. 3 blade Maxprop feathering prop. I used some white vinegar, lime away, but the real winner was simple, The Works toilet bowl cleaner. this is what I started with...prior to last season. There was a very rough profile with up to 1/8" of lumpy calcium carbonate deposition....this pic doesn't show the poor state it was after another season on Lake Michigan... anyway, my research came up with some good links and info that explained the process to me.... www.corrosionpedia.com/definition/200/calcareous-coatingDefinition - What does Calcareous Coating mean? A calcareous coating is a layer that consists of calcium carbonate and other salts deposited on the substrate's surface. When the surface is cathodically polarized, as in cathodic protection, this layer is the result of the increased pH adjacent to the protected surface. In other words, it is a layer that contains a mixture of calcium carbonate and magnesium hydroxide deposited on surfaces that are cathodically protected against corrosion, due to the protected surface's increased pH adjustment. The importance of calcareous deposits to the effective, efficient operation of marine cathodic protection systems is generally recognized by engineers and scientists concerned with cathodic protection in submerged marine environments. A calcareous coating is also known as a calcareous deposit." "However, a calcareous deposit also hinders thermal conductivity, which is unwanted in connection to a heat exchanger. Thus, it is important to find a solution in which calcareous deposits do not precipitate on the surface. How did you apply the toilet bowl cleaner? Rag, paint brush? If I remove my prop, can I soak overnight in this solution? |
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