Paint removal from aluminium / re-anodizing

[npf1]

Anyone have any knowledge or experience of paint removal from aluminium and re-anodizing?

I've got 32 aluminium steps on the mast that were painted many moons ago. The paint on them is in poor condition and flaking off. As replacing that many steps is going to be rather expensive, I was wondering about the feasabilty of stripping the paint and getting them re-anodized.

Anyone know if this is possible? What stripper shoud be used that won't eat the aluminium?

Thanks in advance.

 

[rudolph_hart]

Anyone have any knowledge or experience of paint removal from aluminium and re-anodizing?

I've got 32 aluminium steps on the mast that were painted many moons ago. The paint is in poor condition and flaking off. A replacing that many steps is going to be rather expensive, I was wondering about the feasabilty of stipping the pain altogether and getting them re-anodized.

Anyone know if this is possible? What stripper shoud be used that won't eat the aluminium?

Thanks in advance.

Many years ago, I stripped a clumsily-painted aluminium boom on a 33 footer using Nitromors. The gold anodising on it was unaffected, and was good enough so I decided not to repaint it.

 

[greenalien]

Don't use anything containing caustic soda! (Sodium Hydroxide).

Any paintstripper containing Methylene Chloride will work on most sorts of paint, but it's very nasty stuff - keep it off your skin, wear eye protection and rinse it away with loads of water. It's always wise to try a small area first to make sure it does the job.

Note that the popular 'Nitromors' brand of paint stripper no longer contains Methylene Chloride, and reportedly doesn't work so well as a result.

 

[KellysEye]

Apparently it is possibel to reanodize a mast but you need a long tank to do it. It might be worth a call to the company that made the mast and ask if they or a contactor anodized the mast and can it be done again. Obviously all fittings need to be removed.

 

[Bosun Higgs]

Re-anodising a mast is impractical. You would need to strip the mast of all non ally fittings and yopu would need to polish the surface because defects would show up worse post anodising than beforehand. And then there is the cost opf transporting a yacht mast there and back.

If you still want to try, I believe Southampton Anodising used to do it.

 

[npf1]

Thanks for the responses so far, but to clarify, I'm NOT trying to ascertainthe feasability of re-anodising the mast, only the 32 steps that are attached to it. Needless to say, they will be removed from the mast first!

 

[alteredoutlook]

Re-anodising a mast is impractical. You would need to strip the mast of all non ally fittings and yopu would need to polish the surface because defects would show up worse post anodising than beforehand. And then there is the cost opf transporting a yacht mast there and back.

If you still want to try, I believe Southampton Anodising used to do it.

My thoughts exactly .........I'd just repaint them with 2 part epoxy paint

 

[Halo]

Anodising is stripped off commercially using a caustic solution. This process tends to dull the surface as the anodise layer goes 50% into the pre anodise surface and 50% on top so the re-anodised parts tend not to look as good as the originals. It should not cost much to do this if you can get them off (start at the top and work down?!) then it should be relatively easy to get them stripped at your nearest metal finsihing company - Google "anodising" to find one . You can get them re anodised after stripping and if you want a really tough coat then "hard anodising" to 40 microns is recommended.
I have had good success painting ally with hammerite special metals primer - it sticks like s**t to a blanket.
Hope this helps
Martin

 

[Watson47]

npf1 ... I understand that it is just the steps you wish to strip and re-coat.

I have just had all of my aluminium, engine crank cases, etc bead blasted in advance of re-painting. Absolutely top class surface for re-coating. In my case I am repainting with an engine enamel, but you have options to paint or re-anodise. I am also sand blasting the aluminium superstructure of my boat and have decided to re-paint using a Jotun system. (PM with your e-mail address if you would like me to send you the Jotun specification)

 

[npf1]

The mast is coming out for a re-rig so it's the ideal time to deal with the flaking paint on the steps. I'm a bit wary of re-painting them as it didn't work last time, possibly due to poor preparation or perhaps due to the forces on the paint when the steps are folded down for use. Plus, painting 32 two piece steps would be a real soul destroying job!

The steps I have look similar to this: http://www.baselinemarine.com/mw/mastwalker.html but I can't tell whether mine were originally anodised or not (the baseline ones aren't, but some other makes are).

Ideally, I like to dump them all in a bucket full of something to get the paint off, then give them to an anodiser. Or, even better, find a company that will do both.

Not too sure bead blasting would be economical as there will be 64 pieces requiring all four sides to be blasted, which, I would have though would take a lot of man hours. But I know nothing about bead blasting so perhaps it is an option.

watson47 - that engine looks fandabi

 

[Bosun Higgs]

Anodising is stripped off commercially using a caustic solution. This process tends to dull the surface as the anodise layer goes 50% into the pre anodise surface and 50% on top so the re-anodised parts tend not to look as good as the originals.

I did that with a black anodised mast on my Prout. Hot caustic soda solution and abrasive pads. A throroughly dodgy process - I was dressed up in plastic protective gear like someone from Porton Down. But it worked.

I painted the mast rather than anodising for the above reasons. Some water based etch primer. Two coats of epoxy primer sprayed on and then two coats of twin pack poly top coat.

Didnt want the black anodising under the paint in case I chipped the paint.

Wouldnt do the job again unless I was broke.

NPF1 - Do you ever use the steps? How often? Are they worth the effort or would it be better just to get rid and forget the rufty tufty bit about going up your own mast whilst single handing in the southern ocean?

 

[npf1]

NPF1 - Do you ever use the steps? How often? Are they worth the effort or would it be better just to get rid and forget the rufty tufty bit about going up your own mast whilst single handing in the southern ocean?

In an ideal world, I wouldn't have them, apart from two or three at the base and a couple at the top. But, the choice I have is keep the steps or have 96 (or is it 160 )holes in the mast to be filled with something. So, keeping the steps seems to be the best route. Hence, trying to work out the most economical way of doing it.

 

[smth448]

I repainted an Alloy mast many years ago. I removed all the paint quite easily with Nitromors. I didn't check if it contained caustic soda first but it didn't dissolve the mast so I assume it didn't. Took the paint off very easily.
I repainted it with International Perfection 2 pack polyurethane in a very fetching blue. I used International Primer of some description, I really can't remember what it was called but it was special stuff for aluminium. Some sort of etching primer I think.
Once finished the mast looked great, made the rest of the boat look even more tatty.
After I sold the boat a saw it a few years later and the finish on the mast was still OK.
So waht I would do is take all the steps off the mast and repaint them. It will be cheaper that anodizing. If you don;t want to put them all back just stick a pop rivet in each hole to fill it up.

 

[BACUS]

paint stripper

Blackfriar paint & varnish remover is ok on ali but check with there tech dept first.
Personally i would remove the steps, strip them and hunt out your local anodizer and ask him\her your best option and what the finish will be like, anodizing is not to costly.
Regards
Bacus