Surfriding Marine Grade Aluminum

[DAG]

Can make your part out of each grade and see how long each lasts :wall:

I started the thread in hopes someone has attempted parts successfully or unsuccessfully using a corrosion resistant alloy without the need to anodize. Regardless of what "part" it was.

What are you making......... From my understanding, Anodizing does not add strength. It is just a coating that is applied electrostatically... Can be removed with EZ-Off over cleaner and heat.

I'm not making just 1 part thus the generalized question, yes some need to be structural some don't. All I wanted to know was quote "what grade aluminum is going to hold up to saltwater corrosion without being anodized"

I don’t think anyone said anodizing adds strength? Although it has been miss interpreted hardness and especially surface hardness is not the same as strength. Tempering an alloy, however, will change both hardness and strength may be where some of the confusion lays.

You say you've sourced 5086 cheap and ask is there anything better, the question is better for what exactly. Grades of aluminum are chosen depending on application. For example you wouldn't try to form or weld seven series and you wouldn't use five series in certain structural applications as it has a lower tensile strength. Each grade has its merits and usage.
Chris.

I specifically asked "what grade aluminum is going to hold up to saltwater corrosion without being anodized" AKA If I make something, anything, for instance a bypass fitting will it show signs of corrosion regardless of other factors, temper, hardness, yield factors. Agreed everything corrodes, but I'm not looking for a 100+ year lifecycle. And no I'm not planning on making bypass fittings… or am I

 

[DAG]

From the looks of it no one here actually knows the answer, or just confused by the question. Yes anodizing helps prohibit corrosion obviously. And Obviously getting parts anodized is not free. If a part hold up to corrosion well without being anodized why pay the added cost. Because its pretty? Because no one every question it before? Because we need our bypass fittings to withstand 36,000psi tensile strength?

 

[yamanube]

From the looks of it no one here actually knows the answer, or just confused by the question. Yes anodizing helps prohibit corrosion obviously. And Obviously getting parts anodized is not free. If a part hold up to corrosion well without being anodized why pay the added cost. Because its pretty? Because no one every question it before? Because we need our bypass fittings to withstand 36,000psi tensile strength?

Probably because it is less expensive to have a less corrosion resistant alum. anodized than go with a higher quality alloy.

 

[MCrider]

If your looking for saltwater resistant why don't you go with S.S.?

 

[Big Kahuna]

you can anodize something in your kitchen!

 

[yamanube]

If your looking for saltwater resistant why don't you go with S.S.?

Or a fiber reinforced nylon?

 

[madness maker]

in the next few months i plan to build an all aluminum 12' mini sprint jet boat, entire hull will be aluminum 1/8" and some 3/16" sheet, i plan on using 5052 and 5086 sheets, and welding with 4043 rod. not coating anything and will be used in salt water, (flushing/cleaning after each use) will not be kept in water when not in use. seems to be what alot of guys who run these boats use.
Super-Corrosion-Resistant
Easy-to-Weld Aluminum (Alloy 5052)


With excellent corrosion resistance and goodformability, this alloy is similar to Alloy 5086 but also has good weldability for a wider range of applications.



Super-Corrosion-Resistant


Aluminum (Alloy 5086)


Choose this marine-grade aluminum alloy for its excellent corrosion resistance and good formability

 

[LimitedSlip7]

Aluminum bronze. There ya go, no need to anodize. As an added bonus, marine life won't grow on it. It's a PITA to machine though. Technically it's only 10% aluminum, but if you are looking for an aluminum that is impervious to corrosion and don't want to anodize it, you're not going to find it. Just use 6061 and have it anodized, it's not that expensive.

 

[DAG]

haha

 

[DAG]

Probably because it is less expensive to have a less corrosion resistant alum. anodized than go with a higher quality alloy.

This is probably the real answer... higher quality alloys cost more money

Its hard for me to believe someone manufactures and ANSI spent the time to have a underwriter's test and wright a spec for a "super-corrosive-resistant" grade aluminum and it still needs additional treatment to slow corrosion further. I have my options about that

 

[skinny]

in the next few months i plan to build an all aluminum 12' mini sprint jet boat, entire hull will be aluminum 1/8" and some 3/16" sheet, i plan on using 5052 and 5086 sheets, and welding with 4043 rod. not coating anything and will be used in salt water, (flushing/cleaning after each use) will not be kept in water when not in use. seems to be what alot of guys who run these boats use.
Super-Corrosion-Resistant

Easy-to-Weld Aluminum (Alloy 5052)


With excellent corrosion resistance and goodformability, this alloy is similar to Alloy 5086 but also has good weldability for a wider range of applications.



Super-Corrosion-Resistant


Aluminum (Alloy 5086)


Choose this marine-grade aluminum alloy for its excellent corrosion resistance and good formability

You have time to build something else?? LOL

 

[Flash-FX]

My experience with (6061,5052, and cast) aluminum & salt water is best to leave it bare. Polishing looks great and helps reduce porosity. Blasting is easiest for older parts that had been exposed to salt already (less work). But which ever way you go, they must be fresh water rinsed then coated with some spray that soaks into the pores of the metal. After every time you ride. Nothing lasts forever.


Powder coating is good for office furniture that doesn't get wet....

 

[Big Kahuna]

Amsoil makes a great spray..... Seadoo does also.

 

[aytee]

the only way you'll get away with using bare alum to be resistant is polish it, and keep coating it with something to prevent direct contact with the bare alum... bare alum itself will not last... doesn't matter the grade... so either you polish it very regularly and coat it with something like Amsoil metal protect (as stated) every time you ride or just buck up and get it anodized and don't worry about it... there is another product i know of that is widely known in the trucking industry called Sharkhide that does an awesome job at protecting alum...

as far as your pushed question... no there is not any bare grade of alum that is more impervious to corrosion than another, the grade is nothing more than the alloy build up of that part to give it the structural properties required for that part

 

[Idok]

whatever waterdawg made his handlepoles out of is raw aluminum...Mine is going to on 5 years and still looks perfect (maybe a slight tarnish, but thats it)

100% salt use

 

[DAG]

whatever waterdawg made his handlepoles out of is raw aluminum...Mine is going to on 5 years and still looks perfect (maybe a slight tarnish, but thats it)

100% salt use

great! good to know

 

[LimitedSlip7]

Actually the alloying elements have quite a bit to do with the corrosion resistance, but you can only improve it so much.

 

[QuickMick]

This is probably the real answer... higher quality alloys cost more money

Its hard for me to believe someone manufactures and ANSI spent the time to have a underwriter's test and wright a spec for a "super-corrosive-resistant" grade aluminum and it still needs additional treatment to slow corrosion further. I have my options about that[/QUOTE



5086 is not "higher quality" than 6061, its just different. The statement above is inaccurate, 5086 is in fact cheaper than 6061 (over here at least) therefor it would be cheaper to make my parts from 5086 even if I still anodized them.
The question you have asked is the same as asking "Whats the best ski for me" without any other information, it would depend on what type of usage ie sit down, standup, racing, freestyle etc. etc. This is why I gave you the answer I did. However to give you a more specific answer to your your specific question yes, it will be fine in the marine environment for a decent amount of time I know this because I use it for certain applications. Selecting the right grade of material for a given job is all part of the manufacturing process don't be fooled into thinking one grade suits all.
Chris.

I thought that to achieve grade 6061 was just to heat treat it an it turns brittle and is not easy to form. I do not know off hand with out looking up in
Sect II what grade 6061 is that has not been heat treated.
I would think 5052 would work as good with out any ill effects with the heat affected zone of a weld, if your welding it.

But like you said, it depends on what the OP is building/making.

 

[LimitedSlip7]

I thought that to achieve grade 6061 was just to heat treat it an it turns brittle and is not easy to form. I do not know off hand with out looking up in
Sect II what grade 6061 is that has not been heat treated.
I would think 5052 would work as good with out any ill effects with the heat affected zone of a weld, if your welding it.

But like you said, it depends on what the OP is building/making.

No, the 6061 calls out the alloying element and percentages of alloying elements; the O, T4, T6 etc calls out the heat treatment.

Welding aluminum will soften the metal around the HAZ, and must be re-heat treated to restore full strength.

 

[QuickMick]

No, the 6061 calls out the alloying element and percentages of alloying elements; the O, T4, T6 etc calls out the heat treatment.

Welding aluminum will soften the metal around the HAZ, and must be re-heat treated to restore full strength.

Yea I knew the T6 6061 was heat treated. HAZ is most often the weak link in heat treated material and 2 1/4, 5 & 9 chrome metals if not heat treated/stress relived after welding. But then again a hand pole isnt holding 10,000 PSI.