Thread: Protecting new unpainted aluminium boat

Contact Quintrex and ask them.

http://www.quintrex.com.au/SiteInfo/Feedback

They should know what the options are.

Rob

Whether to paint or not?

The whole idea of using aluminium to build boats is that as it corrodes - the layer formed protects it from more corrosion!. (But NOT electrolysis which is a totally different kettle of fish from this question).

When you paint it - the idea is to prevent the surface corrosion occurring - and allow the paint to protect the alloy.

Then when the paint gets damaged, chipped etc - from traveling on unsealed roads and beaching the boat etc - well the corrosion starts then stops again as the alloy does what it does and forms a self protective layer of aluminium oxide.

Its important if you do paint it, to protect it - to select a paint that has NO METAL content. e.g old lead based paints, and also copper based anti fouling paints... these should be specifically avoided at all costs.

The metals (lead & copper) have a lower(higher?) valence value (on the periodic table of elements) to the metals contents of aluminium alloy.

As a result - in salt water specifically - the metal in the paint and the aluminium hull can form a wet cell battery (2 dissimilar metals in an electrolyte) and the last thing you need is the aluminium giving up its electrons - to the other dissimilar metals - or the start of electrolysis &/or galvanic corrosion.

In essence this will eat your hull away (under the paint) & if you do any google searches under keywords Quintrex & Corrosion - you will find many forums posts on boating forums, of owners asking why does my quintrex aluminium boat turn to white powder under the paint (usually at waterline) and terms like leaking pin hole corrosion etc etc.

Rather than get into a bun fight about it... I'll just say that paint on a qunitrex is a bad idea - it will hide a multitude of corrosion (& other electrolysis / galvanic corrosion events) sins occurring under the paint, until the damage is already done and you likely won't see / notice them, until its to late!.

Why?

Coz in order to get that famous flared bow..... that quintrex market, you need highly ductile / malleable alloy to stretch form without cracking!.

Highly malleable / ductile aluminum is often not well suited to use in a marine (saltwater) environment.

Add to that quintrex have zero idea how to wire an aluminium boat - and its a sure fire recipe for an early demise of your hull.

I've had this argument on forums with quintrex - and been banned for telling it like it is before today (and their lawyers threaten me even).

Suffice to say this - if it were ME - I'd leave it unpainted.

I'd also pay VERY special attention to how the thing is wired & what zinc (or hydralloy/Mercury) sacrificial anodes you have on your outboard etc.

If you use it in salt water - then for goodness sakes - don't leave it with the trailer hitch (bow) end down on the ground, out in the open, with a galvanized anchor and chain, sitting in a pool of water in the bow...and the battery connected (unless you want it to turn to white powder in your driveway and blow away in the wind).

Quintrex design and build a great vessel BUT you do have to look after them if you want longevity out of them.

Painting them in many cases will just shorten the service life immeasurably - rather than prolong it IMHO.

There are special paints (interlux) that will work and you have to etch prime it first etc - or if its a clear coat, acid wash it (With diluted phospohoric acid) to remove the coating of aluminium oxide first, and that phosphoric acid is damned nasty stuff - absorbs thru your skin lungs eyes and anywhere else it can get too - and dissolves your bones. Best avoided at all costs.

100 times - I say whatever you do - don't paint it!

Lastly, regarding the wiring (specifically of quintrex).

Anyone builds aluminium hulled boats (or steel hulled for that matter) (and knows what they are doing) (and I've built one before today) will tell you that when installing gen sets and 240 volt power, will tell you that voltage at sea in a marine environment with the salt etc will kill you tootsweet.

In such vessel's - the hull is ALWAYS the earth.

For some godly unknown reason Qunitrex - (coz they obviously know no better) wire them up like a 4wd....with 12V battery systems - as if the electrons all behave different because its DC and only 12Volt.

They insulate the hull entirely from the electric system.

When I built my alloy boat - the electrical engineer and naval architect supplied instructions for wiring (to avoid galvanic corrosion as well as electrolysis) and comply with the code for passenger safety.

The very FIRST thing it says is "the hull is the earth and the earth pole of the battery MUST be equi-potentially bonded to the alloy hull structure".

This normally occurs when you bolt your OB on. The transom clamps / brackets etc - are all bonded to the head and electrical system of the OB, via an earth strap inside the cowl... when the securing bolts go thru the transom, they contact the alloy hull and equi-potentially bond it to the earth of the OB body & thus electrical system...

This is how it SHOULD be!

Not so Quinitrex, they go to great lengths to use insulators on the transom (that white bread cutting board material) and special insulation yellow goo on all the bolts so that there's zero electrical contact between the hull and the actual OB.

In a qunitrex usually the hull is NOT the earth... and if ever there's a short - well being only 12 volts, it WON'T kill you.

However - sitting at home in your shed (or outside in the elements) - with salt ocean water spray all over the hull and water trapped in the bottom if the bows down & bung not out - and the battery in and connected - you now have a nice little galvanic cell set up that will & does eat away at your hull metal...

In essence if you don't disconnect the battery (& take it out) when stored - your nuts - with a quintrex.

Paint won't fix a lower grade alloy used to get the ductility to form that fancy flared bow, nor a bodgey wiring job from the factory.

It will hide the damage occurring tho - until its too late - the boats out of its 12 month warranty period and you have your self a lemon colander for a boat - one that turns to white powder in your driveway and blows away in the wind!

Heck I've had all the threatening emails from quintrex and their lawyers etc to tell me to shut up and desist from running their boats down on the internet etc and have told em before today to knock emselves out and sue my sorry butt off - I don't care.

I it was anything but a quintrex - you might get away with painting it.

At the end of the day - you'd be FAR and away better off NOT painting it - is my advice (and the advise got from my naval architect when building my aluminium vessel).

My 2nd vessel (a commercial charter boat) was clear coated and you can't stop it from oxidizing under the clear coat - in fact it looks worse than unpainted when it happens.

So...

Naval architect.
Master 5 (me)

You do whatever floats your boat - but just don't post up asking how to fix all the pin holes at waterline in your quintrex boat in 2 years time - when the warranty's dusted and Quintrex don't want to know you from Adam is all.

I am 100% sure you'll get conflicting advice.

All I can tell you is, they don't know squat!

Quintrex = good boat, but don't paint it! My 2C

Others mileage will no doubt vary.

Cheers

The way I read it the OP doesn't intend to paint the Quintrex.

He just wants some clear protective coating to put over it to keep the shine - wax, clear coat etc.

I hear what you say and totally agree with your comments, having had a couple of alloy boats (Dehavilland) but I don't think it's in line with the original question.

Rob

Yep clear coat is what I have on my vessel now - but it was built that way in 2000 - so 13 years old now...and the parts that have oxidized are more than the parts that are clear, so it look like a bad dose of measles.



Basically they acid washed it and clear coated it.



You might be able to see it starting around the bow section.

It's more even all over now... but thats after 13 years, and some of those, swinging on a mooring in the tropics for 12 months at a time.

Honestly they are better left unpainted - that's what all the cray skippers do....

Just sayin.

Interesting........

If ever I buy a small aluminium runabout, I definitely not painting the freak'n thing!

Simon

A lot of the Quinnies are, painted.

They now export a huge amount of them to the USA.

Because they are relatively cheap and look like a glass boat with that "carolina flared bow" and the paint - the yanks seem to love them.

The big difference between them and us is of course - they have so many huge man made dams and lakes, they have freshwater to burn compared to us...

Just about every man nad his dog has a freshwater lake holiday cabin / house... with a boat (and boat house) on it.

Not all the yanks live by the ocean and fish in the sea....

Painted quintrex boats in a freshwater lake don't suffer the same corrosion / galvanic cell problems - that we here who fish in the ocean seem too!.

That's coz the electrolyte (saltwater) part of the wet cell battery is missing.

All alloy boats are prone to this in saltwater and thats coz the outboards have dissimilar metals, bronze or brass bushings, stainless prop shafts, and aluminium castings for leg parts etc etc... put that on a aluminium boat and put it in saltwater and without the right sacrificial anodes - the hull would be toast in a short span of time.

You see it a lot in marina's, where it only takes one vessel with shore power, and leaky stray current - for the underwater gear on neighboring boats (stern drive legs - props and rudders and rudder posts etc) to all get eaten away in say 6 months...

But freshwater lakes... the old painted quinnie might well last a few generations without issue.

Saltwater is the killer!

Say you swing that alloy boat - on a mooring in the ocean (or pen it in a marina with galvanized steel fittings (bolts) on the timber pylons under the water!.

You have an alloy hull and a zink and steel bolt in close proximity in an electrolyte - the very definition of a wet cell battery (With the mooring the galvanized chain and anchor or steel engine block).... these all set up a wet cell battery effect, when in an electrolyte...2 or more dissimilar metals immersed in an electrolyte.

It's ONLY the sacrificial anodes that keep the alloy hull in tact by giving up their electrons first... and protecting the hull.

Few people consider this - when penning their alloy boat for 4 weeks holiday in the canals and marina where they are staying for eg...

pained alloy boats are OK, IF you wash them thoroughly with fresh water after use in the ocean or estuary's, to remove the salt after each use, allow them to both drain and dry, keep them under cover (in a shed), with the bow raised and bungs out, and if possible disconnect the battery or better remove it from the boat altogether.

Wire them correctly they would last even longer.

Use a better quality marine grade alloy in the first place (then you couldn't stretch form that fancy flared bow) and they would last longer again.

In freshwater they could well be the ultimate boat in so many ways.

If you are aware of the potential for problems and take care to avoid them...then they can be a fine boat for a hell of a long time.

Too many people are not aware is all.

Thanks for detailed comments!

The 2nd poster was right though - I am getting an unpainted tinnie so was really after advice on whether it is a good idea to seal the bare aluminium with anything. I was hoping to preserve some of the original look of the shiny 'new' aluminium look. I am NOT painting my boat otherwise.

would value any thoughts/advice on this thanks
Sean

Originally Posted by Timless Timber

There are special paints (interlux) that will work and you have to etch prime it first etc - or if its a clear coat, acid wash it (With diluted phospohoric acid) to remove the coating of aluminium oxide first, and that phosphoric acid is damned nasty stuff - absorbs thru your skin lungs eyes and anywhere else it can get too - and dissolves your bones. Best avoided at all costs.

isn't phosphoric acid in coke a cola and a bucket load of fertilizers not to mention milk
so a bit hard to avoid at all costs
don't get wrong it is an acid and if you intend to use it you should look up the appropriate material handling information especially respirators but i think claiming that it will dissolve your bones if wash your boat is a bit sensationalist

Phosphoric acid | National Pollutant Inventory
nasty maybe but no mention of turning you into an invertebrate

sean
I Know a few guys that use lanox but it gets expensive they seem to recon it works well though i use it on the out board and it works well on that (my boat is painted)
they also wash down with ct 18 truck wash after use in salt water as its suppose to have a salt neutralizer in it
hope this helps

cheers
Harty

Sorry - my Bad.

I meant Hydroflouric acid.

http://www.sciencelab.com/msds.php?msdsId=9924296

Potential Acute Health Effects:
Very hazardous in case of skin contact (corrosive, irritant, permeator), of eye contact (irritant, corrosive), of ingestion. Liquid
or spray mist may produce tissue damage particularly on mucous membranes of eyes, mouth and respiratory tract. Skin
contact may produce burns. Inhalation of the spray mist may produce severe irritation of respiratory tract, characterized by
coughing, choking, or shortness of breath. Severe over-exposure can result in death. Inflammation of the eye is characterized
by redness, watering, and itching. Skin inflammation is characterized by itching, scaling, reddening, or, occasionally, blistering.
Potential Chronic Health Effects:
Non-corrosive for skin. Non-irritant for skin. Non-sensitizer for skin. Non-permeator by skin. Non-irritating to the eyes.
Non-hazardous in case of ingestion. Non-hazardous in case of inhalation. Non-irritant for lungs. Non-sensitizer for lungs.
CARCINOGENIC EFFECTS: Not available. MUTAGENIC EFFECTS: Not available. TERATOGENIC EFFECTS: Not available.
DEVELOPMENTAL TOXICITY: Not available. The substance may be toxic to lungs, mucous membranes, skin, eyes, bones
teeth. Repeated or prolonged exposure to the substance can produce target organs damage. Repeated or prolonged contact
with spray mist may produce chronic eye irritation and severe skin irritation. Repeated or prolonged exposure to spray mist
may produce respiratory tract irritation leading to frequent attacks of bronchial infection. Repeated exposure to a highly toxic
material may produce general deterioration of health by an accumulation in one or many human organs.

That's a little more detail....

Nasty stuff.

Just need the right name for it.


Cheers

Originally Posted by seanlark

Thanks for detailed comments!

The 2nd poster was right though - I am getting an unpainted tinnie so was really after advice on whether it is a good idea to seal the bare aluminium with anything. I was hoping to preserve some of the original look of the shiny 'new' aluminium look. I am NOT painting my boat otherwise.

would value any thoughts/advice on this thanks
Sean

Like some sort of varnish or something like that?

Originally Posted by Timless Timber

Sorry - my Bad.

I meant Hydroflouric acid.

http://www.sciencelab.com/msds.php?msdsId=9924296



That's a little more detail....

Nasty stuff.

Just need the right name for it.
[/FONT]

Cheers

I thought you had mixed that up. I use Phosphoric Acid at work and there are no special safety precautions beyond the normal ones associated with corrosive chemicals. Same as caustic, which is another chemical used in a different step on the same cleaning job.

I have heard some horrific stories about Hydroflouric acid tho. It is used for pickling stainless steel and I don't have any for that reason. It is extremely dangerous.

Dean

I'm finding this more 'n more, as I get older Dean, I mean one thing and say (or type) another.

I just figure they are 'brain pharts' or something.

My kids and my Missus (SWMTSWTP) pick me up on it, more and more frequently of late.... and what REALLY worries me is, there's a history of Dementia/Alzheimer in my family.

I subscribe to "if you don't use it, you lose it" and I am afraid.... I'm losing it more 'n more each day.

Harty and RC thanks for comments - yes I was after some sort of clear finish or 'varnish' to be able to spray on the new unpainted tinny hoping to maintain the new-look lustre of the boat. I have read they use something on the exterior of big buildings that have been cladded with aluminium and it works well to keep them looking shiny and clean and almost maintenance free.

In regard to use of LANOX or similar I would have assumed it would not dry and may 'wash off' over time? Am I wrong on that? Maybe it dries to a thin film? Whatever one uses it obviously needs to be able to take something of a water, wind and salt and sometimes bump belting.

I have also emailed Quintrex for advice and asked my local Quintrex dealer who thinks there may be something. They previously asked Quintrex but I don't think heard back on it.

thanks
Sean

Have a look at NZ Surtees boats they use a brushed aluminium finish with Nyalic coating. Nyalic, the worlds most advanced nylonic clear coat solution for marine, architectural and industrial corrosion protection

Quinnies are pretty reliable boats, nice choice. I would paint the inside though. Having had 2 pack epoxy on a Stingray plate alloy - never ever again - look great but a nightmare to protect from stone chips while towing.