Sacrificial Anode: Zinc vs Aluminum

[Peahead]

I have always used zinc anodes on my outboards ( and sometimes on tabs ) but wondering about what others think of using the aluminum anodes. Apparently West M. seems to be pushing them due to being better for the environment and I think they are cheaper. Also they should not be used with aluminum boats.

Makes me think I should just forget about paying for more zinc and just bond up my metal parts to a neighbours aluminum boat and 'sacrifice' his boat ! lol

 

[Foxsea]

I have always used zinc anodes on my outboards ( and sometimes on tabs ) but wondering about what others think of using the aluminum anodes. Apparently West M. seems to be pushing them due to being better for the environment and I think they are cheaper. Also they should not be used with aluminum boats.

Makes me think I should just forget about paying for more zinc and just bond up my metal parts to a neighbours aluminum boat and 'sacrifice' his boat ! lol

http://www.martyranodes.com/content/martyr-resources/Aluminum Anodes.pdf

Aluminum alloy anodes (aluminum, zinc and indium) look like a winner!

 

[MRACER]

I use magnesium for my alumn boat, but I think they are the best anode no matter what boat--more money though?

 

[searun]

Interesting read, thanks for sharing. I place a lot of zincs on my boat. Far cheaper than the alternative.

 

[Peahead]

I use magnesium for my alumn boat, but I think they are the best anode no matter what boat--more money though?

My understanding is that:
-Aluminum for saltwater and brackish water
-Zinc for saltwater
-Magnesium for FRESHWATER

From what I have read, I can't find a reason to buy zinc anode over aluminum if you don't have an Aluminum boat ( last longer, cheaper, lighter and more effective as sacrificial anode to protect corrosion)


If Magnesium is considered a freshwater use I suspect in saltwater it wouldn't last very long


http://www.martyranodes.com/content/martyr-products-services/custom-anodes/index.php

 

[MRACER]

If Magnesium is considered a freshwater use I suspect in saltwater it wouldn't last very long

tHAT IS A GOOD THING, NOT A BAD THING..TOLD YOU IT WAS MORE EXPENSIVE, but what is your boat and motors worth vs. 35.00 mag anodes?

 

[ReelSlim]

I agree with MRACER about it being a good thing. If you pull your boat each year and the zincs still look new then I would be worried. They are supposed to be the weakest link as a sacraficial anode. If your boat is in the salt a lot you can be sure you are loosing electrons somewhere! lol And unfortunately if not from your zincs then it will be your leg or tabs or whatever else it can rob from that isn't bonded to an anode. I change mine every second season for the number of days mine is in the water each year. I have never tried the aluminum anodes but would like to hear the results from people that do use them. Although longer life is not an advantage to me.

 

[Peahead]

If Magnesium is considered a freshwater use I suspect in saltwater it wouldn't last very long

tHAT IS A GOOD THING, NOT A BAD THING..TOLD YOU IT WAS MORE EXPENSIVE, but what is your boat and motors worth vs. 35.00 mag anodes?

Thanks MRACER. I appreciate your input as thats why I started this thread. Obviously I totally agree with your $35 anodes vs your motors cost of course but I am wondering if thats a mute point in this case ... if my boat is being protected properly with zinc.
SO the main question I have then is: Are you saying that if my zincs are deteriating at a fairly fast rate that my motors are still at risk for not being properly protected whereas if I had a magnesium anode, there wouldn't be that risk ? I have always been one to consider just adding more zinc if I felt they were deteriating quickly ( and obviously doing regular re and re ).

My zincs get eaten fairly fast because I moor all year. As long as zinc does it's job and protects my motor I likely wouldn't choose magnesium because for me that would mean $200 haul outs every time I wanted to do my anodes and my time to do that. At the rate I change my zincs now, I am not sure I could keep up with changes at the rate magnesium may need. With needing my boat on the hard for all those extra anode changes, you are certainly correct about extra costs to use them. Of course if my zincs are not protecting my boat properly and I am risking getting corrsion (where a magnesium anode would prevent that) then I would switch to magnesium and spend the money on all those extra haul outs.

I have read that Aluminum is MORE efficient as an anode ( compared to zinc) AND lasts longer - is that possible I wonder.

 

[MRACER]

Peahead- For your application I think you are doing the right thing--As ReelSlim stated- the last thing you want is long lasting "zinc's"--My alumn boat is on the trailer 90% of the time, so I want the quickest corroding anodes possible for the short time it is in the salt. The lighter weight makes me feel better for gas consumption!lol-- no really..I never even knew there was such a thing as mag anodes prior to owning a metal boat- Used Zincs on my trawler and was always happy--you might look at a hooka set up for your boat with a light dry suit (would pay for itself with the first zinc change)

 

[searun]

So not to sidetrack your thread here, but on a slightly related note has anyone found a cheap supplier of zincs. I have a lot on my boat and because I'm moored year round go through a few sets each year.

 

[profisher]

I use zinc anodes and either brush (stainless brush) them once a month when the boat comes out of the water for maintenance and bottom cleaning. The zincs that are hard to brush completely clean I will brush on Muriatic Acid to take off the scale. If you don't remove the scale that builds up over time they are not working very effectively. I'm happy when they look worn and pitted, they are working.

 

[Island Fish Lifter]

On my Pursuit, I installed large slab zincs on each trim tab, then bonded each motor. Made the OEM zincs last a long time.

 

[Peahead]

I use zinc anodes and either brush (stainless brush) them once a month when the boat comes out of the water for maintenance and bottom cleaning. The zincs that are hard to brush completely clean I will brush on Muriatic Acid to take off the scale. If you don't remove the scale that builds up over time they are not working very effectively. I'm happy when they look worn and pitted, they are working.

Wow, out for maintenance once per month ?! You must be trailering her cause at Vancouver's haul out prices, that would be a huge chunkof change each year (Wish I had still had a driveway to store my trailer otherwise I would have kept the trailer just for boat maintenance !

On my Pursuit, I installed large slab zincs on each trim tab, then bonded each motor. Made the OEM zincs last a long time

Yes that was my thinking, just add more zinc.....then you would expect each zinc to deteriate slower ( because more zinc to do the same work) Wouldn't your motors already be bonded though ....being electrical start ?

It was also my thinking that given a zinc anode is new or clean and it is properly installed/bonded, the deteriating slower could also mean less electrical current in the marina therefore less deteriation in that situation is actually good news because it would likely be telling you the marina is relatively "clean" of stray electrical

 

[Peahead]

Still looking for some Aluminum anode info - anyone used Aluminum with any pros/cons ?

 

[Dave S]

Still looking for some Aluminum anode info - anyone used Aluminum with any pros/cons ?

I have aluminum anodes on my Yamaha. They break down faster but as said by others, that's a good thing. Nothing bad to say about em.

 

[Peahead]

I have aluminum anodes on my Yamaha. They break down faster but as said by others, that's a good thing. Nothing bad to say about em.

Thanks Dave , excellent.

 

[searun]

On my Pursuit, I installed large slab zincs on each trim tab, then bonded each motor. Made the OEM zincs last a long time.

I have the round style ones on my trim tabs. Are the one's you have mounted those large thick slabs designed to be attached to the transom of commercial boats? Wondering how they mounted up. Sounds like a good idea worth looking into - sorry for all the questions.

 

[Dave S]

pulled these off last summer. The anode top left is zinc, the rest were aluminum.

 

[Foxsea]

Still looking for some Aluminum anode info - anyone used Aluminum with any pros/cons ?

Here's some FAQ info:http://www.performancemetals.com/anodes/AnodeFAQs.shtml (check out the powerpoint under Useful Documents at the end. - great explanations.)

I bought jobber zincs for my Suzuki outboard but the mechanic nixed them for the following reason: Older anodes for outboard units were made of zinc but in response to corrosion problems, Mercury and Johnson/Evinrude/OMC started selling the aluminum anodes in the early 1990’s. Other manufacturers like Suzuki and Yamaha have long-since switched to aluminum alloy too. If you use jobber zinc anodes you could invalidate your warranty! For outboards and sterndrives, always buy the OEM parts. A few more bucks but the peace of mind is worth it. Remember to keep anodes clean and change the internal engine anodes, as well. Dave S. has put up that great graphic that totally convinced me of the value of the aluminum anodes. Thanks, Dave.

 

[Peahead]

Here's some FAQ info:http://www.performancemetals.com/anodes/AnodeFAQs.shtml (check out the powerpoint under Useful Documents at the end. - great explanations.)

I bought jobber zincs for my Suzuki outboard but the mechanic nixed them for the following reason: Older anodes for outboard units were made of zinc but in response to corrosion problems, Mercury and Johnson/Evinrude/OMC started selling the aluminum anodes in the early 1990’s. Other manufacturers like Suzuki and Yamaha have long-since switched to aluminum alloy too. If you use jobber zinc anodes you could invalidate your warranty! For outboards and sterndrives, always buy the OEM parts. A few more bucks but the peace of mind is worth it. Remember to keep anodes clean and change the internal engine anodes, as well. Dave S. has put up that great graphic that totally convinced me of the value of the aluminum anodes. Thanks, Dave.

Thanks Dave S and Foxsea,

Yes that anode photo Dave posted does tell a story for sure. I installed OEM (Yamaha) anodes on my 200 HPDI but I didn't realize that Yamaha switched - so as you suggest ( Yamaha switched to aluminum) I must have aluminum on there now. Well after seeing the photo Dave posted ( and the other posts about aluminum) I am going to return the Martyr zincs I just bought.

On my other boat with twin 150's its very noticable that one leg anode is 25%-30% eaten and the other one on the other leg is about 5-10% eaten. I think you guys have prety much allowed me to figure out why now = one is zinc, one is aluminum !