Hi, I am new to Aluminumalloyboats.com and this is my first post. I have been reading through some of the threads and have come across quite a bit of info regarding mill scale on aluminum. I have come to the conclusion that ideally an aluminum boat should be acid etched to eliminate the mill scale, to avoid corrosion.
I am in the process of getting a boat built on Vancouver Island where I live and the manufacturer that I plan on using does not etch their boats. Should I be concerned by this? Is this a deal breaker, or can I easily etch it myself after I purchase it? I don't want to throw names out there, but this manufacturer is very popular and has built hundreds of boats with many happy customers.
I appreciate any replies/suggestions.
Cheers!
Is etching necessary on a new hull?
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gandrfab
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Re: Is etching necessary on a new hull?
Welcome, 
you have come to the right place.
you have come to the right place.-
kmorin
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Re: Is etching necessary on a new hull?
submerged, as the self-appointed mill scale gnat-zee of the AAB.com site; I'll take a stab at a reply.
Your question seems to question bring up the question; Who's boat is it? Is this your boat? you're paying for it so you own it? Or is this boat the builders' property until he says it's yours? Maybe the question is "When does it become your boat?"
In the first instance you might be able to influence the issue of etching if you're inclined? but in the second instance perhaps the builder is not willing to accommodate your requirements (you did mention that YOU had concluded about mill scale) in which case you'll have to decide if you feel if etching is 'necessary'?
There is not much to discuss about etching a finished boat, because you can etch or have the boat etched- anytime - on the exterior surfaces. The discussion comes about the non-accessible surfaces and if they are etched or have retained mill scale?
So you could offer to have he mill scale removed (at your expense) before the sheet is cut, after it is cut but before its tacked up, or after it welded to a certain stage? It would be pretty hard to control and etch of finished cabin spaces or below decks or inside fuel tanks after they're built or welded out. The tanks can be managed but the other two general categories are kind of hard to imagine that you can get the mill scale off after a certain stage of the build.
Deal breaker? It's your deal, how convinced are you and of what? I'm not trying to be difficult but that's what it boils down too. Do some major builders etch or clean materials all before or during construction, yes, do other even more builders not even bother; YES! What do you see of the corrosion on brand new high dollar boats where there's mill scale left on and in them? I've seen plenty examples that seems to indicate this builder's view is short sighted, but you're the one making the deal so only you can decide if there is no way to get your conditions met if that breaks the deal?
You can get the outside etched yourself anytime you want to spend/do that work. The question becomes what about the interior surfaces, could the builder make an accommodation, at some stage, allowing those material surfaces that will be covered in final construction to be stripped mechanically or chemically of mill scale? Once you explore your own 'bottom line' then the builder's willingness (or not) to meet your needs, you can decide all your own questions.
a few more cents of opinion on the subject of mill scale on new builds.
Cheers,
Kevin Morin
Kenai, AK
Your question seems to question bring up the question; Who's boat is it? Is this your boat? you're paying for it so you own it? Or is this boat the builders' property until he says it's yours? Maybe the question is "When does it become your boat?"
In the first instance you might be able to influence the issue of etching if you're inclined? but in the second instance perhaps the builder is not willing to accommodate your requirements (you did mention that YOU had concluded about mill scale) in which case you'll have to decide if you feel if etching is 'necessary'?
There is not much to discuss about etching a finished boat, because you can etch or have the boat etched- anytime - on the exterior surfaces. The discussion comes about the non-accessible surfaces and if they are etched or have retained mill scale?
So you could offer to have he mill scale removed (at your expense) before the sheet is cut, after it is cut but before its tacked up, or after it welded to a certain stage? It would be pretty hard to control and etch of finished cabin spaces or below decks or inside fuel tanks after they're built or welded out. The tanks can be managed but the other two general categories are kind of hard to imagine that you can get the mill scale off after a certain stage of the build.
Deal breaker? It's your deal, how convinced are you and of what? I'm not trying to be difficult but that's what it boils down too. Do some major builders etch or clean materials all before or during construction, yes, do other even more builders not even bother; YES! What do you see of the corrosion on brand new high dollar boats where there's mill scale left on and in them? I've seen plenty examples that seems to indicate this builder's view is short sighted, but you're the one making the deal so only you can decide if there is no way to get your conditions met if that breaks the deal?
You can get the outside etched yourself anytime you want to spend/do that work. The question becomes what about the interior surfaces, could the builder make an accommodation, at some stage, allowing those material surfaces that will be covered in final construction to be stripped mechanically or chemically of mill scale? Once you explore your own 'bottom line' then the builder's willingness (or not) to meet your needs, you can decide all your own questions.
a few more cents of opinion on the subject of mill scale on new builds.
Cheers,
Kevin Morin
Kenai, AK
kmorin
Re: Is etching necessary on a new hull?
Thank you for the feedback kmorin. I have not yet purchased the boat, so perhaps I do still have some bargaining power. The boat builders up here tend to be a bit on the arrogant side...It's sort of like they're doing you a favor by building you a boat at any cost. However I do think I will press them a little harder to (please remove the mill scale). Like you suggested, I can offer to compensate them for the extra trouble. It would be nice to have it removed from all surfaces. I guess in the end it would be up to me to trust that they actually did it.
I suppose I need to man up and have this conversation with the builder. It's slightly intimidating when talking to a person about changing a product that they are so proud of. Especially when they insist their way is best.
I suppose I need to man up and have this conversation with the builder. It's slightly intimidating when talking to a person about changing a product that they are so proud of. Especially when they insist their way is best.
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gandrfab
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Re: Is etching necessary on a new hull?
Nut up and don't be a push over, Self employed and managers are hard to push around.
The learning curve my 1st few years in business was something else, most of my customers are self employed or management
I may not be able to get my point across on a keyboard, but I have been in hundreds of verbal matches with customers, from selling a pair of rod holders to full towers to fixing a lawn mower,and with my recent move welding on airplanes.
The more people you have to deal with the better you get at dealing with people.
And remember, "Be nice." It goes a long way.
The learning curve my 1st few years in business was something else, most of my customers are self employed or management
I may not be able to get my point across on a keyboard, but I have been in hundreds of verbal matches with customers, from selling a pair of rod holders to full towers to fixing a lawn mower,and with my recent move welding on airplanes.
The more people you have to deal with the better you get at dealing with people.
And remember, "Be nice." It goes a long way.
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kmorin
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Re: Is etching necessary on a new hull?
submerged,
Since there are several stages where the process can be done to the different parts or surfaces that may be covered in later stages, and an overall white metal etch before rigging and after all welding.... I think it would be possible to find a common ground on this issue or question. But if the firm has a long waiting list for work, and doesn't want to change their practices then you may have an impasse?
IN terms of "trust a builder to do what you've asked?" There is the school of thought in contracting that various stages are paid only when an inspector- you or a surveyor- approve the previous stage of work and give the go ahead for the next stage. This could be seen by a builder where clients have just 'let them build' - to be intrusive. But we go back to the idea of who's boat is this and when would it become yours? At the signing and down payment -its yours? Or when you make the final payment -it yours?
I don't know the practices there AND it would be a major inconvenience for them to stop work waiting while you traveled to see an stage inspection. On the other hand, they can see if a stage is coming up and notify you in advance, commonly done, and you're there to see the bilge framing is cleaned of mill scale before the deck goes down. Since you're paying, and they're offering the service; it seems reasonable to me to be able to negotiate before you sign the contract and your input needs to be in the wording of the contract. But that's just my few cents for my money- I wouldn't mind shopping builders if one didn't provide the boat to the level I wanted; if I was paying.
In the final consideration its your money, why buy what you don't' want? If they did 80% of the boat you want would you buy? If they did 90% or 95% - I'm offering an argument that; at some percentage of disagreement you'd refuse to do business with their firm. So again, this is encouragement to set you goals of performance for their services, make sure its written in the contract with provisions for inspection and if you don't get what you need to do business - don't. That is your final leverage - your refusal to buy- but a firm with a waiting list may not find your stance liveable and you'd be forced to move on to an other builder.
At least you can voice your concerns, explain you've seen online lots of pictures of welded metal boats with mill scale and humidity corrosion, you want to etch or buff the scale off, and you'd like to have a discussion about the three or four times in your build this could happen with the least impact on the schedule- still getting your desired results and you'd like a draft of their building contract to go to your solicitor to review it. Not sure if that will be seen as argumentative or not? But all of it seems reasonable to me.
I think there's a difference between minimum standards in an owner or prospective client and that same person being confrontational or argumentative. To me everything is on the table until the deal is struck. What if you wanted their 29'er instead of their 28'er? Are they going to say -"No! you look like the 28'er type of guy?"
What if you wanted one or another brand of instrument or engine or some other variable? Wouldn't you be accommodated? So if you're told "NO; under no circumstances will we consider removing the mill scale from any surface except the weld zones" (hopefully they do that on their own!!?) and you try to show your willingness to pay and accommodate their work schedule- you may have to live with your own conditions and find another builder??
Not sure I understand the idea that you're not the customer, and the business axiom " the customer is always right (even when he's wrong) " is one that seems to apply? I admit I've had potential owners walkout on me on lots of deals, but they were usually price not services. IF you're willing to pay their price PLUS the added to handle your materials the way you want and the builder won't- well- there's other builders.
Cheers,
Kevin Morin
Kenai, AK
Since there are several stages where the process can be done to the different parts or surfaces that may be covered in later stages, and an overall white metal etch before rigging and after all welding.... I think it would be possible to find a common ground on this issue or question. But if the firm has a long waiting list for work, and doesn't want to change their practices then you may have an impasse?
IN terms of "trust a builder to do what you've asked?" There is the school of thought in contracting that various stages are paid only when an inspector- you or a surveyor- approve the previous stage of work and give the go ahead for the next stage. This could be seen by a builder where clients have just 'let them build' - to be intrusive. But we go back to the idea of who's boat is this and when would it become yours? At the signing and down payment -its yours? Or when you make the final payment -it yours?
I don't know the practices there AND it would be a major inconvenience for them to stop work waiting while you traveled to see an stage inspection. On the other hand, they can see if a stage is coming up and notify you in advance, commonly done, and you're there to see the bilge framing is cleaned of mill scale before the deck goes down. Since you're paying, and they're offering the service; it seems reasonable to me to be able to negotiate before you sign the contract and your input needs to be in the wording of the contract. But that's just my few cents for my money- I wouldn't mind shopping builders if one didn't provide the boat to the level I wanted; if I was paying.
In the final consideration its your money, why buy what you don't' want? If they did 80% of the boat you want would you buy? If they did 90% or 95% - I'm offering an argument that; at some percentage of disagreement you'd refuse to do business with their firm. So again, this is encouragement to set you goals of performance for their services, make sure its written in the contract with provisions for inspection and if you don't get what you need to do business - don't. That is your final leverage - your refusal to buy- but a firm with a waiting list may not find your stance liveable and you'd be forced to move on to an other builder.
At least you can voice your concerns, explain you've seen online lots of pictures of welded metal boats with mill scale and humidity corrosion, you want to etch or buff the scale off, and you'd like to have a discussion about the three or four times in your build this could happen with the least impact on the schedule- still getting your desired results and you'd like a draft of their building contract to go to your solicitor to review it. Not sure if that will be seen as argumentative or not? But all of it seems reasonable to me.
I think there's a difference between minimum standards in an owner or prospective client and that same person being confrontational or argumentative. To me everything is on the table until the deal is struck. What if you wanted their 29'er instead of their 28'er? Are they going to say -"No! you look like the 28'er type of guy?"
What if you wanted one or another brand of instrument or engine or some other variable? Wouldn't you be accommodated? So if you're told "NO; under no circumstances will we consider removing the mill scale from any surface except the weld zones" (hopefully they do that on their own!!?) and you try to show your willingness to pay and accommodate their work schedule- you may have to live with your own conditions and find another builder??
Not sure I understand the idea that you're not the customer, and the business axiom " the customer is always right (even when he's wrong) " is one that seems to apply? I admit I've had potential owners walkout on me on lots of deals, but they were usually price not services. IF you're willing to pay their price PLUS the added to handle your materials the way you want and the builder won't- well- there's other builders.
Cheers,
Kevin Morin
Kenai, AK
kmorin
Re: Is etching necessary on a new hull?
I am now working with a different builder who has agreed to acid etch all of the aluminum before welding. The boat is going to cost a bit more, but I think it's worth it. This builder is also making a complete custom boat which has given me more things to consider, such as hull thickness and flotation.
This boat is going to be 18' plus the 2' pod with an 8' beam. I have the option of 1/4" bottom and 3/16" sides, or 3/16" bottom and 5/32" sides. The latter would be cheaper to build and more economical to tow and run, but would I notice a big difference in ride quality and durability?
My next question is whether or not flotation is necessary. The builder usually puts spray in foam in the smaller boats <20' , and no flotation in boats >20'. He has agreed to do whatever I wish. I have read that foam flotation leads to corrosion and extra weight so I'm leaning towards no flotation. However is this a reckless thing to do in an 18' boat? It will have a self bailing deck with 32" sides and a 10" bulwark around the bow.
I appreciate all the feedback I got on the mill scale topic and I'd really like to hear any thoughts on these next questions.
This boat is going to be 18' plus the 2' pod with an 8' beam. I have the option of 1/4" bottom and 3/16" sides, or 3/16" bottom and 5/32" sides. The latter would be cheaper to build and more economical to tow and run, but would I notice a big difference in ride quality and durability?
My next question is whether or not flotation is necessary. The builder usually puts spray in foam in the smaller boats <20' , and no flotation in boats >20'. He has agreed to do whatever I wish. I have read that foam flotation leads to corrosion and extra weight so I'm leaning towards no flotation. However is this a reckless thing to do in an 18' boat? It will have a self bailing deck with 32" sides and a 10" bulwark around the bow.
I appreciate all the feedback I got on the mill scale topic and I'd really like to hear any thoughts on these next questions.
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goatram
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Re: Is etching necessary on a new hull?
In the States it is required for boats 20' and under. I am completely comfortable not having Flotation on current boat and on my old 21' Northriver. If the Boat sinks I don't want her back. 
John Risser aka goatram
33' RBW with twin 250 Hondas (Aliens)
2015 Ford F350 Dually
Master of R&D aka Ripoff and Duplicate
33' RBW with twin 250 Hondas (Aliens)
2015 Ford F350 Dually
Master of R&D aka Ripoff and Duplicate
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kmorin
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Re: Is etching necessary on a new hull?
sub, I don't think the durability question is too much to say no. A 3/16" bottom 0.160" topsides 20' LOA skiff would be fine for as long as you breath, and probably the great grandchildren too.submerged wrote: but would I notice a big difference in ride quality and durability?
However, ride quality is not so simple to answer. So let's say the thickness change of a 1/16th inch of metal on the bottom and 20-30thou' on the topsides isn't as much as having one more person in your boat? So, no, it won't effect ride quality near as much as the design of the bottom's V the chines arrangement and the outboard's install. Will weight effect 'ride'? yes it can but the small amounts you're discussing are not going to be major ride issues.
Let's say you build lighter wt? go thin? Well if that rides 'too hard' add some fuel. Add some gear if you need more displacement.
My only concern with the thickness is to confirm the builder is using a slightly different (tighter) framing on the thinner material? If so, then there is one more consideration- it may be more expensive in labor to frame in thinner material? So the few pounds of initial material may be saved if the labor to frame thinner material is 'that much greater' than framing the same size for thicker materials? If the labor will remain the same?? (ask?) then go thinner it won't be a enough lighter to make a difference and will last just fine.
As to foam. Chaps mentioned our CG requires foam (even in welded plate boats!!! ) under 20'-0" LOA. Your boat is probably 20' LOA so I'd say you can get by without it?
I want to run around my pet peeve about foaming metal boats- one more time!
#1 to put a deck in welded boat you weld in the deck.
#2 to confirm the welds are are water AND VACUUM tight the entire bilge/below decks area is air pressure tested to about 2.5 to 3.0 psig.
#3 if the deck makes a tank that is pressure and vacuum proof - when does the foam do its job of 'displacing water'?
#4 tearing the bottom open is not happening, all welded aluminum boats will bounce/glance/ricochet/slide off of all 'tearing underwater obstructions'
#5 When in the world does the foam ever show up as a necessary design feature?
#6 How is foam a safety feature when the entire welded structure is a bullet proof welded, pressure tested, metal bubble?
What am I missing? I've never added foam to any boat I've built and they've never needed it, I've seen them awash, rolled in the surf, driven over by large tenders, abandoned in a dry breaking surf on a rock shore but I've not seen any time since my first boat in 1976-7 where foam in an air tested void would improve one of my boats' performance- and I wholly totally and completely think the regulation (re:foam) is easily demonstrably idiotic.
Now let's move to corrosion for a quick review.
there are two main types we're concerned with inside a boat. One is galvanic or different types of metal together- like a SS bolt into aluminum- not much of a battery but it is a battery. Next is crevice or its close cousin 'poultice' corrosion both operate similarly and that is where foam can (all kinds) can be a major contributing factor.Anytime there is a very narrow or almost flat fit between aluminum and anything, including other pieces of aluminum we have a space called a crevice where water will 'wick' into the void by capillary action. Once in there the water looses oxygen to the metal's oxide first- then the water becomes acidic and the metal becomes anodic (an anode/cathode cell between the metal and water) and the cell is born and keeps 'working' by adding small amounts of water - EVEN humidity of the ambient air.
So, if you spray or put cast foam blocks of foam into the bilge of a metal boat, and properly vent the deck with an atmospheric vent/breather/temp expansion vent tube (this is correct building practice on sealed deck boats) there is a potential for the humidity in the air to condense in the cold bilge plates (hull under waterline) and leave a few drops of water to wick under the foam and begin the crevice cell.
I have repaired others' skiffs with foam where they did not air test the voids holding foam and found that in a few seasons some of these net skiffs had 'rotted' out from inside their tanks. I've also cut open and modified my own work only to find some voids completely dusty and dry and other showing some waterline from past presence of water in the bilges. But not leaving foam in my voids I've not found any with corrosion cells started.
What so many boat owners don't seem to comprehend, and I'm not saying you have this misconception, is that the foam in a void cannot perform any safety feature contribution until that void is torn open and seawater is allowed inside. What exact state is the boat in at that point? Why again is foam added? I get the distinct sense that its' like worrying if the windshield wipers will work under water- maybe not but why would it matter then?
Again, these are opinions of the very opinionated AAB.com mill scale gnat-zee, who has more than a few ideas that are not widely accepted so they require lots of salt to go with my few cents of opinion.
Cheers,
Kevin Morin
Kenai, AK
kmorin
Re: Is etching necessary on a new hull?
Which builder are you going with now? I've spoken with the guys at Silverstreak about a 18' Hard top...expensive.