Aluminum corrosion help...>>

[Heron]

The custom frame over my cockpit, being untreated aluminum, has corroded over the past 14 years. As I'm getting ready to replace the lace on cover, this would seem to be an ideal time to deal with this. How to clean up? Sanding appears necessary as the corrosion is pretty knarly. Then protective coatings? I've had friends use Protective Zoop seal on polished car manifolds and aluminum wheels, but they are now out of business. This appears to be a similar product:
https://www.summitracing.com/parts/ssl-1001
Homepage:
http://www.shineseal.com/index.htm

Any familiarity with this or anything similar?
Thanks for any input.
Here's a shot of how the frame looks now:

 

[sunchaser]

Several different painting products and preparation techniques will work, but the top will have to be disassembled to do it right.

In fresh water, unprotected Al for Biminis and enclosures is so so, but in salt water it can be a challenge. This is why polished SS is commonly used.

 

[Heron]

Several different painting products and preparation techniques will work, but the top will have to be disassembled to do it right.

No intention of painting as that will take me down a path that will not be pretty if (when) that coating fails. Disassembly other than removing the lace on cover, is not an option and this will have to be done on the boat. Boat is in fresh water...
At this point I'm thinking Sanding/polishing, then a sealer like that linked unless there are better ideas!

 

[RT Firefly]

Greetings,
Mr. H. Agree on disassembly but you're re-doing the lashing anyway...Perhaps a coat of a POR15 product would work... Stop Rust with POR-15 - We Know What Permanent Means!

Just saw your post above...I hear ya on the coating and I meant disassembly as in just removing the cover.

 

[Xsbank]

Aluminum in salt is problematic. If you use a coating it will eventually fail and the corrosion will be worse. Everybody has seen a Muir windlass that was painted/coated once and the surface is all lumpy and there is a white powder underneath? As soon as the coating is breached and you add a little water and restrict the oxygen, you get serious corrosion. The correct aluminum alloy will protect you from lots of corrosion but you still get spots where some surface corrosion appears. That seems to be what you've got.

I do not recommend aluminum for any "yacht," certainly I recommend that you never paint nor coat your aluminum. Aluminum windows are much better than wood but much harder to repair when they finally fail. On my boat, a previous owner glued non-skid strips on the deck (wet aluminum is very slippery with bare feet) but the alloy has corroded underneath, not enough to compromise the integrity of the Al, but it is very unsightly. I have been peeling it all off and it has left a mess.

If you do paint your aluminum, it takes very careful prep and you cannot subsequently ignore it. If a breach in the coating occurs, you will need to prepare and repaint the area immediately. I would say this is harder to do than with wood and takes as much attention.

If you insist on aluminum for some reason, weight or strength, get the correct alloy and leave it alone. The natural aluminum coating will protect it and its only maintenance is an occasional washing.

In your case, remove the canvas and then scrub the pipe with a scotchbrite pad. Depending upon the alloy it will form an aluminum coating quite soon. Wash it well and put the canvas back on. It will return to its existing state eventually but it will not be better if you paint.

Painted aluminum super yachts must be a nightmare - must be why they have such huge crews and why you and I don't have one!

My credentials:

 

[Heron]

I do not recommend aluminum for any "yacht," certainly I recommend that you never paint nor coat your aluminum.

In your case, remove the canvas and then scrub the pipe with a scotchbrite pad. Depending upon the alloy it will form an aluminum coating quite soon. Wash it well and put the canvas back on. It will return to its existing state eventually but it will not be better if you paint.

Painted aluminum super yachts must be a nightmare - must be why they have such huge crews and why you and I don't have one!

My credentials:

I agree.....No paint! I made a set of Weaver Bracket risers and stand-offs a few years ago and powdercoated them thinking this would work...Unfortunately, once that finish was breached I got the bubbling and peeling you refer to. My second set, I Plastidipped (a rubberized spray on coating) and they have held up nicely.. My window frames are anodized, so no issues after 28 years.

I think cleaning up as you say will work, and the best solution. I think a sealer, from what I'm reading, will buy me a few years.......

 

[Comodave]

You might check out Shark Hide. I have not used it just saw it on Ship Shape TV. They were polishing pontoon boats with it. I think it was supposed to leave a protective coating of some type.

 

[Xsbank]

Just stay away from any product that contains hydrofluoric acid!!!
Not hydrochloric but hydrofluoric. It polisheds aluminum beautifully but it will kill you in a particularly nasty way, it penetrates your skin and eats calcium. If it spills on you and you can get immediate help you might be ok but if you have a delay, there is no antidote and no stopping it. The first thing it does is eat your nail beds and your fingernails will fall off...then...never mind...

DO NOT USE IT!

 

[sdowney717]

https://www.amazon.com/dp/B0002LBKG...TF8&colid=2OSRFQ2URHVIT&coliid=I39AEPTEWAUEKM
Something like this, has UV protection and highly rated, people say it is good lasts at least a year.
I have been wanting to try it myself.

Klasse High Gloss Sealant Glaze is a highly concentrated acrylic formula glaze for new cars and oxidation-free surfaces. High Gloss Glaze provides an additional protective layer over the All-In-One with an exceptionally brilliant mirror-like shine. High Gloss Sealant Glaze creates an elastic, non-chip, shrink-proof, heat and scratch resistant - protective seal against ultraviolet rays, salt water, acid rain and industrial pollutants for up to 12 months. Use this glaze on all paints with or without clear coats, glass, fiberglass, Plexiglass, plastics, metal surfaces, enamel, tiles, Formica and all non-porous surfaces. It is anti-static, non-abrasive and contains no ingredients harmful to paint, metal or plastic.

Look at these large lizard creatures wrestle.
From a friend I have in Thailand.
https://www.facebook.com/clipdonjung/videos/951803588190583/

 

[Heron]

https://www.amazon.com/dp/B0002LBKG...TF8&colid=2OSRFQ2URHVIT&coliid=I39AEPTEWAUEKM
Something like this, has UV protection and highly rated, people say it is good lasts at least a year.
I have been wanting to try it myself.

I use Klasse (all in one in the red bottle) on all my cars and have for years. It is pretty amazing for a UV paint protection system. If you have shiny gelcoat I'd say go for it, though use the all in one. The sealant you linked too is very hard to use. Not sure it would be appropriate for this UV protected aluminum as it seems to be an acrylic film and not an etching type metal protectant...

 

[sdowney717]

I use Klasse (all in one in the red bottle) on all my cars and have for years. It is pretty amazing for a UV paint protection system. If you have shiny gelcoat I'd say go for it, though use the all in one. The sealant you linked too is very hard to use. Not sure it would be appropriate for this UV protected aluminum as it seems to be an acrylic film and not an etching type metal protectant...

I suppose clean the aluminum of all corrosion would the first step.
I would scrub it with a scratchy nylon scrunge and dish soap, unless there is a chemical cleaner?

Sure why not use a UV acrylic waterproof sealant?
Under your cloth cover, it should last even longer with no direct UV exposure.

 

[Heron]

I suppose clean the aluminum of all corrosion would the first step.
I would scrub it with a scratchy nylon scrunge and dish soap, unless there is a chemical cleaner?

Sure why not use a UV acrylic waterproof sealant?

I think that's the way. Need to look into possible chemical cleaners...

Having had a bad experience with Polyglow (acrylic sealer) that was pretty deteriorated when I bought the boat, I think I'll stay away from those products....They are miserable to remove when they start to go..

 

[sunchaser]

I've had 3 SeaRays, all used anodized powder coated Al liberally that showed no signs or deterioration in fresh water. I've been around small to mega yachts made of Al and painted, all looked great. Yes, don't scratch them without redoing the finish correctly.

But these are different issues than working with a dozen or so pieces of Al tubing. Heron, if you want to spiff it up to first class and forever, have you priced out SS tubing?

 

[Bacchus]

Heron

My $0.02...

Prep steps & associated effort will depend on what final finish you are shooting for.
I posted a good reference on Metal Buffing & Polishing in the TF Library Misc Section... a lot of detail that might not apply - of interest might be the "hour-glass" shaped buff that might prove helpful if you are wanting to use a drill vs hand work w/ compounds for the prep.

I have seen ref to Alumetron products but can't provide any actual experience.
I've considered using it on an alum fishing boat but so far it's just a consideration.

 

[Heron]

Heron

My $0.02...

Prep steps & associated effort will depend on what final finish you are shooting for.
I posted a good reference on Metal Buffing & Polishing in the TF Library Misc Section... a lot of detail that might not apply - of interest might be the "hour-glass" shaped buff that might prove helpful if you are wanting to use a drill vs hand work w/ compounds for the prep.

I have seen ref to Alumetron products but can't provide any actual experience.
I've considered using it on an alum fishing boat but so far it's just a consideration.

Thanks for the tip on the hour glass shaped buff.
http://www.stewmac.com/Luthier_Tools/Tools_by_Job/Tools_for_Finishing/Buffing/Foam_Polishing_Pads.html
Might make that part of the job easier. Your link, though interesting, has the "Boat surcharge" and may (or may not) be better than a simple (Mother's) metal polish. The actual alumetron part of that kit may also be similar to the Sealants mentioned previously though the description is that of a coating. I Think going for the Polished shiny look would be labor intensive...I think a cleaned up brushed finish will be fine, then a sealant of sorts.

Stainless would be nice, but the Cost would be prohibitive I'd imagine, to duplicate..

 

[Bacchus]

Steve
"I Think going for the Polished shiny look would be labor intensive...I think a cleaned up brushed finish will be fine, then a sealant of sorts.

Stainless would be nice, but the Cost would be prohibitive I'd imagine, to duplicate.."

Agree - you might consider a good wax as the sealant...
Collinite does offer a Metal Cleaner/Wax that might be worth a try - I have used and like other Collinite products but no experience w/ their metal wax

 

[Heron]

Don.....You gave me an idea. The Hour shaped buffs make polishing look pretty easy. Just ordered a few to polish the lower, outer rails to a shine. There is little to no pitting on these and should shine up nicely and easily with the buffs. They are the most visible parts of the framing. The inner frame, under the cover has a lot of Pitting so maybe just a clean-up to brushed and a seal there...

Thanks!

 

[cardude01]

Aluminum corrosion help...>>

I recently sanded all the bubbling powder coating off my aluminum windows. It was a pain, and I though about re coating with something, but have decided to leave them bare. I do coat the frames periodically with Woody Wax, which leaves a film over the aluminum that beads up water and is supposed to protect aluminum.


They look pretty good from 10 feet.

 

[Xsbank]

If you polish the aluminum it will look amazing, for a short while, then it will redeposit itself with aluminum oxide which is what it is designed to do to resist corrosion. Then you can polish it again, and again, and again until the aluminum is all worn away. The purpose of choosing the correct alloy is to let it develop that coating and it's distinctive grey patina. The dull grey looks crappy on a yacht but some people (8^)) like it.

My opinion in using it on a yacht is it is cheap, looks good for a year or a few until the boat is off warranty. Then, any coated aluminum starts to look like crap but the builder doesn't care. The mess is left to the subsequent owner to fix. Usually, that fix is a compromise.

We have a friend with a Coastal Craft, aluminum. Excellent boat that he commutes with but when he ordered it, he had it painted. He completely regrets that decision now, his coated boat looks like crap. The paint is all bubbling and the white powder is rampant.

There is a boat near me where the builder masked off all the openings and sand blasted the entire boat. It looks uniform and amazing (although it still looks very grey!). You could try a variation of that on your piping?

 

[Heron]

If you polish the aluminum it will look amazing, for a short while, then it will redeposit itself with aluminum oxide which is what it is designed to do to resist corrosion. The purpose of choosing the correct alloy is to let it develop that coating and it's distinctive grey patina. The dull grey looks crappy on a yacht but some people (8^)) like it.

Hence the sealant. There are good reviews (in the car scene) of shine and gloss being maintained for quite some time with the right sealing after polishing. I don't have the option of choosing another alloy. Had I (and not the PO) contracted for this 14 years ago, stainless would have been the choice...and likely not excessively more expensive as most of the cost was obviously in the labor to design and build this frame..

I do like the look of sandblasted aluminum though...

 

[cardude01]

I didn't polish my window frames. Just lightly sanded with fine grit paper on the final step for a brushed finish. It looks ok to me.

 

[Heron]

I didn't polish my window frames. Just lightly sanded with fine grit paper on the final step for a brushed finish. It looks ok to me.

Sounds like a good plan. Bet removing that powdercoat was a PITA! Consider a sealant as mentioned an it'll probably look good longer...

 

[Gordon J]

so what your saying is...

Just stay away from any product that contains hydrofluoric acid!!!
Not hydrochloric but hydrofluoric. It polisheds aluminum beautifully but it will kill you in a particularly nasty way, it penetrates your skin and eats calcium. If it spills on you and you can get immediate help you might be ok but if you have a delay, there is no antidote and no stopping it. The first thing it does is eat your nail beds and your fingernails will fall off...then...never mind...

DO NOT USE IT!

I shouldn't use hydroflouric acid to clean the mustache off my hull.

Gordon

 

[Heron]

I shouldn't use hydroflouric acid to clean the mustache off my hull.

Gordon

Use Oxalic acid....Cheap and effective.....

Save the calcium...

 

[Seevee]

Use Oxalic acid....Cheap and effective.....

Save the calcium...

Heron,

Is the Oxalic acid a product to get rid of corrosion or what? How do you use it?

 

[Heron]

Heron,

Is the Oxalic acid a product to get rid of corrosion or what? How do you use it?

I buy it in powder form from Ebay/Amazon. A few $$ for a few lbs. Mix an ounce in a 1 qt spray bottle. Useful to remove Tannin and brown water stains from the hull. Does not hurt paint or gelcoat. Works similarly to the commercial stuff at $20/Qt.

 

[Seevee]

I buy it in powder form from Ebay/Amazon. A few $$ for a few lbs. Mix an ounce in a 1 qt spray bottle. Useful to remove Tannin and brown water stains from the hull. Does not hurt paint or gelcoat. Works similarly to the commercial stuff at $20/Qt.

Heron,

For stains I use muriatic acid diluted, or a product called Phoz. Both excellent for stains on hulls, and neither hurt the hull.

Was hoping for a product that would dissolve corrosion.

 

[Bacchus]

Heron,

Is the Oxalic acid a product to get rid of corrosion or what? How do you use it?

Oxalic acid works on (iron) rust stains (& tannin on hull) - never used it or heard of it working on alum??