Aluminium Oxide

[Seagoon]

G'day all,

Am in the final stages of my tinnie painting preparation. Have found that what i though was just surface pitting is actually more sinister, and rather much deeper than 1st thought - about 0.5mm or so. Have got the aluclean doing its job thanks to some encouragement and advice from a fellow FR :-) just had to add more elbow grease and a wire brush :-)

But, there is still rather a lot of oxide in the pitts. Im not worried about it, so long as i know that the paint is gonna stick to it. Will be doing the etch/prime/fill/topcoat type of approach.

Is there any product that converts aluminium oxide so that paint will stick to it reliably and longish term? With steel you can by the converter that neutralises the rust so that you have something stable to paint. If the paint will stick to the al oxide, then thats fine.

I have attached some photos of the boat, for interests sake. One is of it after stripping and before the wire brush. The next is after wire brushing, showing some pitting that was a result of a stainless steel bimni fitting on a rail, and the last is a test etching of a small spot. The etchant certainly cleans the Al, and removes some oxide too. Am planning more experiments with it b4 final etching.

Thanks for any comments.

[vision21]

I know a mob that may help, not sure if its O.K to post the web details here though.

[Geoff]

I know a mob that may help, not sure if its O.K to post the web details here though.

Vision 21 PM Swordfisherman or Mrs S. They can advise

Regards

Geoff

[Geoff]

Jon I think there are two other aspects that you may want to take into consideration.

A reoccurance of the problem

I have limited knowledge on this aspect but understand it is caused through electrolysis.

This is an electrical charge going through the boat & when in contact with salt water it attacts the softest part of the aluminium.

On my previous boat it had a self destructing replaceable anode . This being the softest spot the electrolysis attacted this area & left the rest of the boat alone.

Also , I always disconnected the battery when the boat was at home

Perhaps there are other raiders more knowledgeable than I who can advise

Filling in the pitting to provide a smooth surface

Prior to painting my boat it had some arears that needed attention. Good quality body filler seem to do the job , I used Plastie Bond. Available from most hardware stores. With all the banging & bouncing over the waves it never came away

Regards

Geoff

[vision21]

Thanks Geoff I will get onto that.

Cheers

Tony.

[Guest]

Tony has the go ahead to post it up as per our PM and we thank him for asking first

Cheers Stewy

[Geoff]

Jon Just for comparison , here is the anode on my boat , 3.5 years old & 133 hours on the water & it has taken quite a beating

Regards

Geoff

[vision21]

This is a company that has some fantastic steel and aluminium treatments I have always called them for advise otherwise you end up spending heaps of time looking through the site.

ppc.au.com [not .com.au]

[Seagoon]

Thanks everyone for your input :-)

Geoff, you aint wrong! With that amount of corrosion, think of how well it has protected your boat! I must look into that, absolutely.

Im getting close now! Plan to etch and paint this weekend :-)