Uh oh! Is this corrosion?

[wetwhopper]

Hi all. Its been awhile. Hope to find your fish lockers full and your and your spirits high.

As I was applying Sharkhide to my hull I started noticing some white blotches forming on my hull. When you rub some of the larger ones with your fingers you can feel them very slightly. I wash my hull thoroughly with fresh water and apply 2 coats of Sharkhide annually. While the majority of my fishing is done in salt, my boat has never spent the night in it.

I will be calling Koffler on Monday for their take, but want to have a little knowledge before talking to Joe. I don't know if Koffler acid etches their boats. Any thoughts? Thanks!

[kmorin]

w'whopper, the second photo shows aluminum with mill scale on it; therefore the boat in the photo was not etched to remove the mill scale as mill scale is shown in the photo.

For the 1/millionteenth time:
#1 mill scale is porous, (but shiny)
#2 mill scale holds water vapor, (even when hauled on the trailer)
#3 mill scale has a small galvanic (electrical potential difference) differential from underlying aluminum alloy,
#4 mill scale supports small cells of crevice corrosion that are initiated by the galvanic differences plus water
#5 mill scales 'starter' cells become crevice corrosion depending on humidity (cell renewal)
#6 removing mill scale (or storing a boat in the desert) will eliminate this cause of corrosion to marine alloys.
#7 little white flowers are the visual indication of the above items happening before your eyes.

I think I'm this site's mill scale gnat-zee, so my hard line is to be taken will all the salt you'd like: but

.....you're welcome to look at the many other posts (here) of even name brand boats with this problem, not to mention the several posts I've made about being approached by owners of new, name brand boats in this area with this identical problem. And there are a few images of my 'old' boats that are thirty or forty years old that are still just dull grey aluminum; since they were etched when they were built.

I have not seen any fully acid etched boats with this condition. I have seen it on mill scale covered boats quite frequently so I think etching would a good step? I'm prepared to be in error, I very often find myself there, but even if the many large scale builders continue to refuse to etch- my take is they're wrong to take that stance with their boats.

Cheers,
Kevin Morin

[wetwhopper]

Hey Kevin. Thanks for the response. Yes, I get that there's corrosion (mill scale) forming on my hull and I'll take your word that the boat hasn't been acid etched... I guess what I need to determine is, what now?

I did call Joe (Koffler Boats in Oregon) and forwarded him the same pics I posted on this thread. He assured me it was nothing to worry about... Just to keep an eye on my zinc and replace when needed. He says all aluminum boats form light marine corrosion.

He's always been a guy that I trust but assuming it's something I should be worried about, what's your advice? I looked you up and you have far too many threads for me to read through in this lifetime and to be honest I'm not much of a boat builder. I like to drive them, do my basic maintenance and fish. Could you assume I'm a engineer moron and lay things down for me in a " lay mans language" kinda way. thanks for your patience.

[kmorin]

w'whopper,

Even if the builder is willing to accept corrosion, you don't have to. Unfortunately this fellow is in error, or Pacific and the other high end boats wouldn't bother to etch would they? ( I know that plenty don't bother to etch, but who you gonna believe? Them..... or your lying eyes?) I notice the builder is willing to alloy YOUR boat to corrode, wow that's one generous guy!

I've mentioned too many times here that other factory builders have similar lines, but those of us who acid etch don't show any flowers decades after the build- you decide it's your boat.

Etch the boat to eliminate corrosion, that's as simple as I can put it!

Cheers,
Kevin Morin

[Chaps]

If you are going to etch it you need to get the layers of shark off first

[kmorin]

Chaps, good point- I wonder if the SharkSkin on the mill scale is what's stopping drying out the cells?

"Coated In"?

cheers,
Kevin Morin
Kenai, AK

[wetwhopper]

O.k. now were getting somewhere. I'm all for acid etching. Didn't know that was still an option. Now I just need to research on how to do it and what the cost is.

Also, stop using Sharkhide till the boat is fully acid etched.

Now were talking.

Thanks : )

[Chaps]

Chaps, good point- I wonder if the SharkSkin on the mill scale is what's stopping drying out the cells?

"Coated In"?

cheers,
Kevin Morin
Kenai, AK

I don't know, aluminum with mill scale seems to have a mind of its own and whether its coated or bare it tends to do the white pimple thing if it was not removed by the builder (or somebody).

By the way, wetwhopper, shark can be removed with lacquer thinner, use a spray gun to wet out a portion of the hull with it and then rub with a cloth towel that is also wet with the thinner. If you have a thick build-up it will take some work.

GO HAWKS!

[wetwhopper]

Lacquer thinner. check!

Bring on the Packers or Cowboys!

Also, is there anyone with a good reputation that specializes in acid etching used hulls in Washington?

[Rendog]

Hi guys I am a new member, just minutes old!

I could not believe what Wetwhopper had posted as I believe I am having the exact same problem that I just discovered 2 days ago! Of course when you spend a fortune on a boat and then all of a sudden you see this mill scaling corrosion, it is very worrisome when you are not sure what it is! The funny thing is my boat has not been in the water since early October, it did not show any signs of corrosion in late November and then suddenly I just notice it. I am sure its been happening right in front of me, just not noticeable until now. A difference from most is that my boat has only been in the ocean once, the day I took delivery. The rest of the time its been in one of the cleanest freshwater lakes in Canada. I also trailer the boat to and from the lake which caused me to think the diesel particulate from my diesel truck may have cause this, but its mainly from the water line and below. I know it can not be from the batteries as I took them out for storage over winter.

Being new to forums, I hope this is not considered hijacking and I thank kmorin for the info he provided Wetwhopper. I am with Wetwhopper on if there is there anyone with a good reputation that specializes in acid etching used hulls in Washington? Luckily despite living in Canada, I live just minutes from the WA boarder so any info can help the two of us.

I have attached a few pictures just for comparison with Wetwhoppers photos. If anyone thinks it any different please let me know. As for me, I think I'll be calling around Monday morning looking for a place that etches Aluminum for the both of us! I threw in photo of my pride and joy, a 2014 Edge Marine with a Yamaha F200XB, Yamaha T9.9 and a Lowrance electronic package.

Sincerely,

John

[wetwhopper]

Welcome John. That's one fine looking boat you have.

Im with you. It's very disheartening. Hopefully we both caught in time that it won't too big a deal. I was under the impression that you could maintain aluminum By washing your hull thoroughly with fresh water and applying Sharkhide a few times a year. My garage is too small for a boat larger than 17' and knowing my boat would be sitting in the driveway played a big factor in choosing aluminum over glass.

I live two blocks from the ocean which probably doesn't help either. I don't mind if the boat doesn't look pretty and oxidizes some, but The whole mill scale thing sucks!

Let's knock our heads together and see what we can figure out? I think the,guys have pointed us in the right direction but am waiting for a few more members who are also knowledgable to join the conversation with their ideas !

I'm praying this isn't going to cost a gazilion dollars either (while I take a cold shower throwing hundred dollar bill down the drain) lol. There goes my down riggers for next year!

[wetwhopper]

John, check your zinc plate also. Your boat is new enough where I doubt you'd need to replace but you made need to scuff the surface of it for it to work optimally?

[Rendog]

Wetwhopper, thanks for the compliment on the boat! Although I do not use it to its full capability as its only in the lakes, I absolutely love it! Tons of room, rides beautifully, and its the apple in my eye, after the kids and wife of course!

I checked the zincs and they appear to be fine (second photo from the bottom I believe on my original post), but then again being new to boating at this level as well I would not know what bad zincs look like. lol…..

So i have a good article for you to read from kmorin from around 2012. It appears that this problem is more common than we might think as it sounds most major boat manufacturers do not etch the aluminum.

http://aluminumalloyboats.com/viewtopic.php?f=4&t=4139

Although I am still researching as much as I can, it appears that all is not lost for us! The etching process does not sound overly hard but safety practices with the etching acid are a must. It also sounds like we can mechanically remove the mill scaling, but it could be harder to maintain a uniform look than etching.

I know of a smaller boat manufacturer in the Spokane area which I will be calling on Monday to see if he is willing to take on the job of etching and restoring a nice look to the boat. I realize that maybe a little far for you to travel but I will let you know either way.

John

[Rendog]

Wetwhopper, In talking with some guys on Sportfishing BC forum, a few have had the same problem there as well. They seemed to indicate that it could be the Chromium used in the 5086 aluminum alloy, which of course would suggest the problem may never go away. They also seemed to indicate that it got to a certain level over the years and then no longer spread. If that is the case then it might suggest the metal integrity has not been harmed and its just purely cosmetic.

Maybe if kmorin is still reading he might have a bit more to add to it.

Just thought you might find that bit interesting.

John

[kmorin]

I'd like to make a fairly wide sweeping statement so you guys have some relative ease of mind with this thread.

First, note that a main line builder has declared this level of corrosion is 'no big deal' and this is someone with lots of boats to his name, on the other hand I've argued this level of corrosion is important. So if you don't know the metal from long experience yourselves, and two more experienced people seem to be offering (seemingly) conflicting statements or at least points of view, what can you do to become more relaxed about your boats?

I've not tried to give the impression that these beginning corrosion sites will scuttle your boat. (For that you need to look more closely at another thread where the boat has severe corrosion due to copper ion impregnated deck plywood!) So let's resolve these points of view, as best I'm able, in writing- note: I am a poor writer so the results need you each to have some patience and a bag of salt to go with my comments.

The surface corrosion is about 0.001" to 0.006" deep, initially, so if you have a 0.125" (not likely) bottom it will take a long time (three or four decades at the present rate) to put the boat at risk and if the boat is thicker (?) well the time gets longer- right? Therefore...... what the builder mentioned above is observing is; this shallow and slow acting corrosion is "OK" by him, since you've already paid him for his boat, and it will not put holes in the boat for a longer than he'll be responsible for this boat, in years, at this rate of corrosion.

If you divide the current pit depth by the thickness and for the sake of argument say that the rate will remain constant- then it will take a long time to pit through. So is there a risk today: NO.

What have I said? I say that any corrosion is the beginning of the end and I don't and wont' tolerate corrosion if I don't' have too- and I don't. I offer my couple hundred boats that are all baby's butt smooth with dull gray, (no mill scale) unpitted, no white chalky flower finish, and they're as old as the time it COULD take for the corrosion you're showing in pictures to pit through.

So while one point of view is "this is no big deal" my point of view is "this can become a big deal, if you have thousands of $ in your boat??? why put up with it?" The other fellow, and plenty of other builders, already have your thousands so now..... it's your problem. I'm saying that you might want to deal with the problem when its shallow as opposed to deep, which the other builder is not denying comes with time, if allowed to continue?

Your boat; you decide.

What is happening is that two different BLIND people with two different points of view are discussing an elephant: I have my arms around the trunk of and this builder that is mentioned has a hold of the ear. I tell you that the animal is a huge muscular tube and he's saying that the animal is a big, thin, flat skin covered disk. I'm hoping this word picture gives the current readers of this thread the idea that we're not all discussing the same topic from the same point of view?

Do you notice that the advise given #1 acknowledges it's corrosion, #2 argues it's inevitable, #3 is not concerned with your boat? #4 is not looking for a solution for your white spotted boat? I do, and I can't say I find that stance acceptable to me as a boat builder. But I'm only speaking for myself and my work, obvious the other fellow is speaking for his work.

Your boat; you decide.

NEXT

After re-reading this thread a bit, I also see a confusion among the several (general) types of aluminum corrosion. Aluminum can corrode from stray current (#1) where the hull or parts end up acting as anodes for improperly installed electrical system this is ALL a zinc system cant protect: galvanic corrosion #2 where different metals are in contact physically or in water with the aluminum: and last, a series of several versions of crevice corrosion #3.

Since aluminum corrosion has a common chemical (read; molecular level) action and therefore all three general types are related at some degree of explanation (molecular level), this subject can be confusing to those who 'just want to drive' boats.

I don't have time to write a layman's text on aluminum corrosion so I suggest that if you have not, you could search the site for topics/threads where we've tried to help others' inquiries into this fairly technical subject.

I try to give rules of thumb, basic layman's termed replies, but when you're discussing chemical events things have to be pretty exact in order to tell the truth.

Chaps, is there a correlation between these shown pits and some water content? Could the 'below the waterline' location show a metal salt in solution in that body of water that is enhancing a galvanic cell when the boat is hauled and the water runs off, it drips in repeated surface tension location and therefore could be 'salting' a cell location in the mill scale? Just conjecture.

Aluminum Alloy Boats Service and Safety NOTICE:
A note to anyone planning to use lacquer thinner in any way, correct PPE is required even outdoors as the vapor is a solvent for your organs, ingested in the lungs this vapor can and will reek havoc on your organs (kidneys first I think?) and so the minimum is a face sealed (rubber only) half face, APR (air purifying respirator) with organic vapor (charcoal based) chemical cartridges. This is not the same exact cartridge for use with acid etch. If you do not have training with industrial PPE, get the training before taking risks with your health. The chemicals discussed here are toxic, solvents, and can and will kill or maim you if not treated correctly. If you don't understand how to handle them...

DON'T DO IT.

We have lots of threads discussing safety, acid use, brands, types methods and suggestions to look for tanker truck service companies who use aluminum cleaners all the time in their work. The services to wash a 40' over the road tanker with acid and a 25' skiff are not unrelated.

rendog, the idea that a given alloy component Chromium is the reason for this surface spot corrosion is not valid as near as I understand the Chrome components' relative reactivity within the metal alloy. Copper... yes, but then 5086 is without. I agree this idea applies to 6063 underwater, or 6061 in some underwater applications, but 5086? I can't see the chrome contribution to reaction- the copper in both alloys (lots in 6063) will 'rot it out' (corrode away) over time.

I've seen lots of boats that don't have this surface spot corrosion ever happen. Those boats had no mill scale left on to initiate the problems shown. ALL the boats I see with this seem to have mill scale, so that leads me to focus on the mill scale not the underlying alloy's composition. Maybe if someone showed spot corrosion on an etched boat, I could begin to look at other causes, I'm not a chemical engineer or metallurgist, but logically, I see the common thread being mill scale left on the material.

Cheers,
Kevin Morin
Kenai, AK

[wetwhopper]

Kmorin, I sure appreciate your free advice and your time. I will definitely take heed, put the down riggers on hold and get this mill scale issue resolved Asap! My wife says I can't have a fort (hardtop) till I retire (at least ten years away). This boat has to last and I'd love to pass it down to my sons. Thanks again. I'll be looking for a reputable outfit who has some expertise in removing mill scale and acid etching the boat. Oh boy! Another adventure!

[wetwhopper]

Rendog, thanks buddy and I'll be sharing any info or resources I come up with reg our situation.

[gandrfab]

OH no , I have used about a gallon of lacquer thinner a year for the last 13 years to clean marks and hand prints of my pipe before I weld it.

[Chaps]

I appreciate Kevin's sentiments on protecting oneself when using potentially harmful chemicals and warning labels should be heeded.

By all rights I should be dead considering the stuff I've inhaled over the years, case in point I used to work summers when I was in high school refinishing bowling lanes when the product applied was traditional lacquer (1960's). The atmosphere inside of the building was so volatile that we typically had to get a permit from local fire departments in order to do the jobs and they would station a crew with a firetruck outside in the event the place went off needless to say each season at least a couple of bowling alleys somewhere in the country would blow with the roof ending up in the parking lot.

That's when I learned the benefits of drinking whiskey after work. It was about the only thing that would wash the lacquer dust down your throat. PPE's? Hah, never knew about 'em, probably the only thing available back then was surplus WW1 gas masks Still kickin' on social security!

[Marcus]

Do you leave the A/B switch on or the batteries connected? Just curious

I have a 17' Koffler Baybee that I've heavily used in saltwater and it doesn't look like that at all. Your bow eye looks particularly crusty. My bow eye looks like new. I rinse heavily with fresh water after every use (no soap, just rinse) and the boat is stored in my garage. I remove and brush the zinc every year, and touch it up with the brush every few months. The zinc has not deteriorated much at all. Boat is 3 years old and I have 300-400 fishing days on it, mix of salt and fresh. I fish salt all summer and freshwater the rest of the time. there is no crustiness anywhere on the hull, there are darker areas where the mill scale has rubbed off that are oxidizing faster, particularly around the water line, but these areas and the boat overall are very smooth to the touch and there is no flowering or pitting anywhere.

Koffler is building me a 23/26 offshore baybee this year, hopefully should start soon. I sent Joe a 225 honda in a crate last month. Last time I was at the shop there were a few 15-20 year old alaska saltwater charter boats and landing craft type boats they were reconditioning (new paint, new upholstery, etc...) and repowering, they get good long term reliability out of their hulls.

Marcus

PS EDIT - your boat is still very shiny overall compared to mine - when I say "doesn't look like that at all" what I mean is that your photo appears to show crusty white powdery areas, particularly on the bow eye and extruded keel chine- I don't have any crust on mine like that

[wetwhopper]

Marcus, I had a 16' Alumaweld that was going on 12 years old without Sharkhide sitting outside on my driveway with no probs (maybe they were acid etched back then?). I don't know... Other than the fact that I live close to the beach. I'm fanatical about rinsing the boat off and flushing the motors after every use. Yes, I leave both batteries in the boat qwith the perco switch in the off position. I crab the boat in the winter and fish spring summer and a little early fall, but the boat has very low hours overall.

Good luck with the new build. I love my 20' Baybee. It gets pretty snotty out here on the coast and she rides very nice Always willing to handle what I throw at her. I wish I could show Joe the boat in person. Eugene is a good four hour trip each way.

I'm hoping to find someone who has the know-how to remove the mill scale and then acid etch the boat. I'll be interested to see what kind of $ were talking about. I'm pretty frazzled that I'm going to have to put non-bling money into a boat that's only four years old.

[kmorin]

to remove the mill scale and then acid etch the boat.

Wetwhopper, acid etching removes the mill scale; that's why its done.

Cheers,
Kevin Morin
Kenai, AK

[wetwhopper]

Lol!
Right! I knew that. Kevin do you know anyone in Washington who does a reputable job acid etching the whole boat including the inside of the hull?

[kmorin]

no, BUTT......
Since painting aluminum usually has sand blasting and or at least etching as a preliminary step, maybe a company that does boat painting would take that on? If you can find a company that will paint the boat...(?) that company may be willing to give a cost to just etch? No real contact in WA - except here on the site. Also you may contact the other skiff builders to see if anyone them will do that job?

Cheers,
Kevin Morin
Kenai, AK

[Chaps]

Acid washing is (or can be) a DIY type of job or like Kevin mentioned, take it to a big rig truck wash where they acid wash aluminum fuel tanks and milk tankers