Flexofold Anodes

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tross

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Following on from the Folding / feathering thread. Quandary mentioned his Flexofold is eating Anodes at quite a rate. I have the same problem. But the end of the season it has all but disappeared - but the strange thing sis the sail leg anode is hadly touched? Where before when I had the old prop the leg anode was about 50% used.

Anyone had / got this issue?
 
My issue is similar but not as enhanced. I've had fixed props on my saildrives for 10 years and the saildrive anodes seem to last for years. A couple of years ago I fitted two 2-bladed Flex-o-folds and I changed the prop anodes this year because they were well used. The saildrive anodes are still fine.

I thought that the Flex-o-fold anodes might be similar to the saildrive anodes and only need changing every 3 or 4 years but that is not the case.

Richard
 
While I have found Darglow an excellent company to deal with, I have one annoying gripe. My address is PA postcode (Paisley) but is categorisd as Highland. When I need a prop anode (aluminium weighing just a few gms.) Darglow steadfastly refuse to mail it, even at my risk, claiming that Royal Mail is unreliable so I have to pay a carrier rate to Highlands more than doubling the price of the part. I have a daughter living in England who I plan to use as a mailbox but it is far from handy.

Like others I found that the zinc leg anodes did not degrade but this year I am using aluminium to match that on the prop. On advice here (Vyv) I have painted the prop. in the hope of extending anode life. We shall see in about a month.
 
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Yes I find the Flexofold anode lasts only about 6 months, which reminds me to arrange a diver to fit new one before the winter. Suitable anodes stocked by local chandler so no postage issue.
Saildrive anode lasts forever, but special stripper compatible ones very expensive.
 
Certainly I found that a well adhered coat of antifoul (Hammerite special primer and Velox plus) reduced significantly the rate of removal of my zinc anode on a Featherstream, now in its third year without replacement
 
tross said:
Following on from the Folding / feathering thread. Quandary mentioned his Flexofold is eating Anodes at quite a rate. I have the same problem. But the end of the season it has all but disappeared - but the strange thing sis the sail leg anode is hadly touched? Where before when I had the old prop the leg anode was about 50% used.

Anyone had / got this issue?
Click to expand...


Surely this is normal . A relatively small zinc anode in close proximity to and connected electrically to a copper alloy ( nickel aluminium bronze ??? ) propellor with a large surface area is going to be consumed fairly quickly. They form an electrochemical cell with about 0.7 or 0.8 volt driving the reactions which occur.

The saildrive anode on the other hand is attached to the aluminium alloy sail drive leg which is only about 0.2 volt on the galvanic scale different in addition to being almost completely covered with an impervious coating. You would not expect it to consumed at a very significant rate, in fact the main electrochemical threat to it comes from the small amount of exposed propellor shaft.
If the previous prop was causing a greater rate of loss of the saildrive anode it was probably because the insulation of the prop hub was deteriorating. The new prop should be completely insulated from the prop shaft and be having no effect at all on the leg anode.
 
I experience the same issue. I’ve used Primacon plus Trilux33 for a few years and it’s helped prolong the life of the anode, subjectively. This season I used Hammerite Special Metals primer plus Trilux and I’ll see the result in a few weeks.


dunedin said:
Saildrive anode lasts forever, but special stripper compatible ones very expensive.
Click to expand...

I buy standard 1-piece saildrive anodes and simply drill a through hole to accommodate the Ambassador Stripper drive dowel.
 
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Thanks to everyone for all the feedback.
The other issue I have is the antifoul loss. Last year much of the antifoul on the blades and body had gone. This season I stripped the whole thing down, keyed it with 80 grit paper, cleaned it with acetone ( twice) used Hammerrite undercoat as per the recommendations here, carefully applied trilux ( rather than velox) and when it was puled out a week ago to have it bum cleaned - blow me most of the antifoul had gone! It not come of in flakes but lots of little 3-4mm jagged spots showing the bare prop . It looks like something below the hammerite is forcing it off . I was wondering if it was some sort of galvanic reaction

any thoughts ?
 
acetone can have contaminants in it; personally I would finished by washing with water containing a v small amount of detergent (such as Fairy Liquid or Decon if you can get it), then several rinses with distilled / deionised water and then allow it to air dry for 2-3 hours before priming with Hammerite special metals
 
tross said:
Thanks to everyone for all the feedback.
The other issue I have is the antifoul loss. Last year much of the antifoul on the blades and body had gone. This season I stripped the whole thing down, keyed it with 80 grit paper, cleaned it with acetone ( twice) used Hammerrite undercoat as per the recommendations here, carefully applied trilux ( rather than velox) and when it was puled out a week ago to have it bum cleaned - blow me most of the antifoul had gone! It not come of in flakes but lots of little 3-4mm jagged spots showing the bare prop . It looks like something below the hammerite is forcing it off . I was wondering if it was some sort of galvanic reaction

any thoughts ?
Click to expand...

This is one of the many photos I have taken of my prop with Velox. This was end of 2014 season, as lifted before washing. No fouling whatsoever but some loss of the Velox in a very characteristic pattern. To me this indicates some cavitation erosion, absent on the back face of the prop. Is this similar to yours?

 
I was surprised to only get 1 year from the anode but it sounds quite typical. One or two chandlers eg Force 4 sell them for quite a lot less than the £40 odd Darglow charge. But Darglow are good about mailing replacement bolts quickly, good service.
 
Thanks for the photo Vic, and thank you all of the other that chipped in.

The anti fouling loss on mine it across the whole surface where the surface "holes are graeter than the remaing antofoul. I was only alowed a short time inspection time when she was lifted out for a bum wash.

I will try and get a photo when she comes out later
 
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