Aluminium boat with corrosion

[Bait_drifta]

Hey guys, 

looking at a second hand  aluminium boat  to purchase first  big boat I will own. It has  corrosion ( paint bubbling)  around the fixtures and flaking off the rear of the boat . The boat is around 18yrs old. 
 

My question is  if I clean up these areas ( etch primer and paint )  and use nylon washes,  tel gel and  rubber backing will that stop the progression of the corrosion spreading?

Also when I lifted the floor I found a stray sinker rolling around under  the floor. Now I know this can cause electrolysis, but how long does it take for it to actually happen?  

 Add some photos for reference. 

Edited January 1, 2023 by Bait_drifta

[noelm]

Yes, that can be cleaned, but it's not a 5 minute job, every speck of corrosion has to be removed. Yes you can use propriety products and insulating washers to help keep corrosion away, but, it doesn't always work. The sinker is impossible to say, there is so many variables.

[Rebel]

Walk away.

You don't need some one elses  nightmares.

Keep looking.

Cheers.

[slowjigger]

Electrolysis is caused by stray current. Galvanic corrosion is caused by different metals being in contact. If the sinker was rolling around and it was a dry area, then there may not have been any corrosion. 

Those pictures don't look too bad for an 18-year-old boat and given that they are not in structurally important areas. Just don't use anything ferrous when cleaning up the corrosion prior to panting. Also etch primer has to be coated with undercoat prior to the final finishing coat. 

[rickmarlin62]

If you lift the floor check for corrosion patches or pinholing in hull and stays  if none you have no probs  the other spots are just cosmetic

[jeffb5.8]

My boat is a 2016 and I have the same corrosion on the ladder mount and a few popping up around fixture points, hard to stop but mine haven’t gotten any worse.

one day I will strip them back and paint but for now with 3 kids I will just keep using it and the kids don’t care.

[Yowie]

My first boat was a Quintrex, and it lasted 42 years until it was at the point of no return. It had many corrosion spots like that, and worse. Pin holes do eventuate in the floor over time. Look at the underside for signs of scraping over rocks and sand banks.

[Fab1]

Me when I saw that.

[Fab1]

Plenty of boats to pick and choose from if you’re patient.With boats it’s always a buyers market.

[Bait_drifta]

Thanks for all  your feed back guys. I will be taking it out for a test run,  I suppose when we get back to the ramp and let the bungs out if there is water in it, it isn’t water tight (maybe due to pins). 

As for the cosmetic stuff I don’t mind fixing that side of things. Also I’m hoping to get e pre-sale inspection done, so an expert eye can potentially pick anything I’m over seeing. 

[Bait_drifta]

12 hours ago, Fab1 said:

Plenty of boats to pick and choose from if you’re patient.With boats it’s always a buyers market.

It’s definitely starting to cool down the boat market is. I’m after a particularly boat so I don’t see many come up. 

[Bait_drifta]

17 hours ago, Yowie said:

My first boat was a Quintrex, and it lasted 42 years until it was at the point of no return. It had many corrosion spots like that, and worse. Pin holes do eventuate in the floor over time. Look at the underside for signs of scraping over rocks and sand banks.

Eventually it will  happen. Hopefully I can get a few years out of it before it does get to that stage. 

[Bait_drifta]

21 hours ago, rickmarlin62 said:

If you lift the floor check for corrosion patches or pinholing in hull and stays  if none you have no probs  the other spots are just cosmetic

 

After doing a bit more research online,  I know what kind of stuff to look for now. 

[Bryant fish]

Check it out properly if you're  happy buy it and use it you're  buying used it won't be perfect as long as price is ok don't worry about cosmetics especially if it's for fishing 

[Fab1]

8 hours ago, Bait_drifta said:

It’s definitely starting to cool down the boat market is. I’m after a particularly boat so I don’t see many come up. 

Well in that case you know your options.Buy it or keep looking for that particular boat if it ever comes up again.Personally I’d widen my horizons and keep looking but it’s your money and your choice.

Good luck with whatever way you go.

[Rebel]

This project is going to end up in Tears.

Cheer.

[frankS]

Sounds if the boat is around the same age as my Savage Scorpion

When I got it there were all sorts of different nuts bolts holding various objects on, mild steel brass etc and there was that sort of corrosion in many areas, I have slowly removed all ( I think ) the offending alian fixtures . I haven't bothered re painting the corroded surfaces as I am just too old to be bothered and as the hull is still in great shape the boat will see my life time out.

Just make sure there are no pit holes in the hull and do as you say clean the affected areas up and re paint and the boat should see you right for several years.

I use plastic tube to isolate the nuts and bolts from the alloy , just cut skinny sections of appropiate size hose or tube and place over bolt and it acts as a protective washer.

Don't be fooled in believing Duralex etc will fully isolate self tapping screws. If the screw is holding the object properly it IS in contact with the alloy. Use the stuff by all means as it does help but it is NOT fool proof. To be double certain there is no contact between different metals multi metre each screw etc .

How about some photos of the boat.

Frank

[campr]

Many years ago I spoke to a retired engineer who was one of oz top metallurgists who told me electrolysis occurs as a chemical reaction between 2 different metals in contact with each other.   The interesting thing he told me was that the heat created by machining (drilling,  grinding etc) can be enough to slightly change the structure of the metal worked (especially aluminium) and therefore create dissimilar metal within the same metal with a slight chance of electrolysis.

I have since drilled any holes in my boat on slower speeds in short bursts to minimise heating  just in case it makes a difference.   Just passing on as an interesting possibility.   Ron 

[noelm]

One of the issues in mass produced boats, is the use of different grades of aluminium, the hull is made from a certain grade, factory made fittings can be made out of cheaper grade, bow rails different again, add to that quick/poor prep before painting, and paint bubbles are just a matter of time! Doesn't matter how much you wash the boat or anything else, it's just a fact of life, that insidious corrosion never sleeps.....

[Welster]

We have gone to quite a bit of trouble to minimise the bubbling a few different methods.

Drilling out fixing points. Using nylon screws washers snd nuts instead of self tapers, aluminium rivets in others. Using sikka flex on some fittings and Tefgel on the few spots with self taping screws.  
 

My thoughts are most of the bubbling paint is caused by paint damage and imperfections. Boat builders take little care putting in self drilling screws damaging the paint around the fixing. As soon as the moisture and air can get under the edge where the paint is damaged the aluminium can oxidise just like on an unpainted boat. It lifts the paint and keeps spreading as it goes.  
 

As frustrating as it is it will happen to all aluminium boats over time.  It will take longer and happen less on boats put together with care.  

I think the aluminium they use for the ladder brackets is rubbish (maybe cast?).  

FYI on my boat we had bubbling soon after purchase.  The manufacturer claimed they use “grease” around the fixings the install because Tefgel is to messy. We never saw any evidence of any “grease” anywhere when removing fittings. 

[dunc333]

the pics bait drifter has  shown look like a classic  quintrex standard shit factory fitout job. i dont know why they keep so much re sale value ,but they do .

[Bait_drifta]

On 1/4/2023 at 8:18 AM, frankS said:

Sounds if the boat is around the same age as my Savage Scorpion

When I got it there were all sorts of different nuts bolts holding various objects on, mild steel brass etc and there was that sort of corrosion in many areas, I have slowly removed all ( I think ) the offending alian fixtures . I haven't bothered re painting the corroded surfaces as I am just too old to be bothered and as the hull is still in great shape the boat will see my life time out.

Just make sure there are no pit holes in the hull and do as you say clean the affected areas up and re paint and the boat should see you right for several years.

I use plastic tube to isolate the nuts and bolts from the alloy , just cut skinny sections of appropiate size hose or tube and place over bolt and it acts as a protective washer.

Don't be fooled in believing Duralex etc will fully isolate self tapping screws. If the screw is holding the object properly it IS in contact with the alloy. Use the stuff by all means as it does help but it is NOT fool proof. To be double certain there is no contact between different metals multi metre each screw etc .

How about some photos of the boat.

Frank

That’s a nice looking boat Frank S, thanks for the tips. It seems pretty common with alloy boats after posting on the page. As for pitting I will be going over again this weekend when I go for a sea trail. It’s an older model stacer 525 around 2004-2005. 
 

[Bait_drifta]

On 1/5/2023 at 5:38 PM, Welster said:

We have gone to quite a bit of trouble to minimise the bubbling a few different methods.

Drilling out fixing points. Using nylon screws washers snd nuts instead of self tapers, aluminium rivets in others. Using sikka flex on some fittings and Tefgel on the few spots with self taping screws.  
 

My thoughts are most of the bubbling paint is caused by paint damage and imperfections. Boat builders take little care putting in self drilling screws damaging the paint around the fixing. As soon as the moisture and air can get under the edge where the paint is damaged the aluminium can oxidise just like on an unpainted boat. It lifts the paint and keeps spreading as it goes.  
 

As frustrating as it is it will happen to all aluminium boats over time.  It will take longer and happen less on boats put together with care.  

I think the aluminium they use for the ladder brackets is rubbish (maybe cast?).  

FYI on my boat we had bubbling soon after purchase.  The manufacturer claimed they use “grease” around the fixings the install because Tefgel is to messy. We never saw any evidence of any “grease” anywhere when removing fittings. 

Yea it’s all about production now no care factor, Manufacturers say anything to make themselves look good. Never heard of grease before that’s a strange one. 

[Bait_drifta]

On 1/4/2023 at 5:23 PM, campr said:

Many years ago I spoke to a retired engineer who was one of oz top metallurgists who told me electrolysis occurs as a chemical reaction between 2 different metals in contact with each other.   The interesting thing he told me was that the heat created by machining (drilling,  grinding etc) can be enough to slightly change the structure of the metal worked (especially aluminium) and therefore create dissimilar metal within the same metal with a slight chance of electrolysis.

I have since drilled any holes in my boat on slower speeds in short bursts to minimise heating  just in case it makes a difference.   Just passing on as an interesting possibility.   Ron 

That’s for the info Ron, definitely be taking it on board  if I was to do any mods on the boat.

[Bait_drifta]

17 hours ago, dunc333 said:

the pics bait drifter has  shown look like a classic  quintrex standard shit factory fitout job. i dont know why they keep so much re sale value ,but they do .

Well the boat is a stacer so pretty much out of the same factory, so i’v heard.