Aluminium porthole frames shedding white crystals

[KAL]

Result! SWMBO has actually ordered me onto the forum!

We have ally portlights, some of which seem to shed white crystals onto the upholstery below.

They are not leaking, but the crystals build up over the course of a couple of weeks then fall off.

Can anyone suggest a treatment for this? Is it a case of wiping down with some proprietary agent, or vinegar or tin foil, or some such?

Helpful suggestions eagerly sought.

Thanks!

 

[VicS]

Result! SWMBO has actually ordered me onto the forum!

We have ally portlights, some of which seem to shed white crystals onto the upholstery below.

They are not leaking, but the crystals build up over the course of a couple of weeks then fall off.

Can anyone suggest a treatment for this? Is it a case of wiping down with some proprietary agent, or vinegar or tin foil, or some such?

Helpful suggestions eagerly sought.

Thanks!

I got our in house paint technologists to do a couple for a friend a few years ago.

Their solution was to grit blast with a soft grit to remove all the oxide etc without removing any metal.

Etch prime and then spray with chlorinated rubber paint.

 

[KAL]

Thanks Vic.

Seems like a major job...much appreciate the reply.

 

[alant]

Result! SWMBO has actually ordered me onto the forum!

We have ally portlights, some of which seem to shed white crystals onto the upholstery below.

They are not leaking, but the crystals build up over the course of a couple of weeks then fall off.

Can anyone suggest a treatment for this? Is it a case of wiping down with some proprietary agent, or vinegar or tin foil, or some such?

Helpful suggestions eagerly sought.

Thanks!

Souds like aluminate crystals.
Has your wife been cleaning them with any caustic/high pH type stuff?
Should only use water to wipe with.

 

[KAL]

Nope. Not cleaned at all, except for a wipe off with a damp scotchbrite every so often.

I was wondering whether a thin smear of Vaseline once cleaned, might have a temporary effect?

 

[Iliade]

Probably, but then you'll inevitably get the stuff on something precious. Why not a wipe of varnish after cleaning off the salts? (Automotive lacquer might be best as it is very clear and tires quickly.)

 

[KAL]

I might try a rub down with some autosol polish first, then give it a go.

 

[[2574]]

We replaced all of our windows last year (Nauticat Pilot house so a lot of big windows £ouch!)

The manufacturer of the new windows advised freshwater wash followed by a wax product at least twice yearly to protect the metal (aluminium?) frames.

 

[Tranona]

I might try a rub down with some autosol polish first, then give it a go.

I sprayed mine matt black. Probably not a permanent solution but can be done in situ. Long term solution is to remove them and have them refurbished with the frames blasted and powder coated.

 

[skipmac]

First I think you should confirm what the white crystals are. From the description I'm assuming the aluminum frames are not anodized, painted or treated in any way. If so, then most likely it is aluminum oxide from the metal reacting but oxide is usually powdery and not large crystals. Any chance there's salt water leaks that are drying on the inside of the windows forming salt crystals?

Not that I'm recommending one put unidentified, possibly noxious powder into their system but personally I would get a small sample off the window and touch it to the tip of my tongue to see if it was salty (and of course expectorate and rinse after).

If you're certain it's corroded aluminum IE aluminum oxide comparable to iron oxide aka rust and you want a proper, long term solution there's two options.

The most time consuming would be to remove the windows strip the frames and take them to a powder coater. Easier and DIY is to paint. Be sure to start with the correct aluminum primer. I use a yellow chromate (Petit two part Alumoprotect is good) but I think there are some other types that work. Follow with a compatible paint in your (or more appropriately SWMBO's) favorite color et voila.

 

[KAL]

First I think you should confirm what the white crystals are. From the description I'm assuming the aluminum frames are not anodized, painted or treated in any way. If so, then most likely it is aluminum oxide from the metal reacting but oxide is usually powdery and not large crystals. Any chance there's salt water leaks that are drying on the inside of the windows forming salt crystals?

Not that I'm recommending one put unidentified, possibly noxious powder into their system but personally I would get a small sample off the window and touch it to the tip of my tongue to see if it was salty (and of course expectorate and rinse after).

If you're certain it's corroded aluminum IE aluminum oxide comparable to iron oxide aka rust and you want a proper, long term solution there's two options.

The most time consuming would be to remove the windows strip the frames and take them to a powder coater. Easier and DIY is to paint. Be sure to start with the correct aluminum primer. I use a yellow chromate (Petit two part Alumoprotect is good) but I think there are some other types that work. Follow with a compatible paint in your (or more appropriately SWMBO's) favorite color et voila.

An incredibly detailed response. Thanks.

 

[KAL]

I sprayed mine matt black. Probably not a permanent solution but can be done in situ. Long term solution is to remove them and have them refurbished with the frames blasted and powder coated.

Ouch!

 

[KAL]

We replaced all of our windows last year (Nauticat Pilot house so a lot of big windows £ouch!)

The manufacturer of the new windows advised freshwater wash followed by a wax product at least twice yearly to protect the metal (aluminium?) frames.

That sounds like an eminently sensible starting point. Thanks Robih.

 

[Tranona]

Ouch!

Hence the matt black paint - last time I actually used a pot of blackboard paint. Easier than spraying and still looked good.

 

[skipmac]

An incredibly detailed response. Thanks.

Very welcome. Just hope a detailed response also translates into helpful (and maybe even accurate).

 

[Hydrozoan]

First I think you should confirm what the white crystals are. From the description I'm assuming the aluminum frames are not anodized, painted or treated in any way. If so, then most likely it is aluminum oxide from the metal reacting but oxide is usually powdery and not large crystals. Any chance there's salt water leaks that are drying on the inside of the windows forming salt crystals?

Not that I'm recommending one put unidentified, possibly noxious powder into their system but personally I would get a small sample off the window and touch it to the tip of my tongue to see if it was salty (and of course expectorate and rinse after). ...

Would not a simpler test be to see if the material dissolves in neutral fresh water – which it should readily do if it is salt (NaCl) crystals, but not readily if it is aluminium oxide?

(I’m not suggesting that especially to avoid touching the tip of the tongue against aluminium oxide with the subsequent spitting and rinsing you suggest, but because I’m not sure if I – or the OP – would necessarily be able to distinguish the tastes with certainty – I haven’t tried, admittedly - whereas the dissolution test should be clear cut.)

 

[skipmac]

Would not a simpler test be to see if the material dissolves in neutral fresh water – which it should readily do if it is salt (NaCl) crystals, but not readily if it is aluminium oxide?

(I’m not suggesting that especially to avoid touching the tip of the tongue against aluminium oxide with the subsequent spitting and rinsing you suggest, but because I’m not sure if I – or the OP – would necessarily be able to distinguish the tastes with certainty – I haven’t tried, admittedly - whereas the dissolution test should be clear cut.)

Easier? But, but you would have to go find a glass, AND fresh water and give up the chance to possibly put a noxious substance in your mouth. Where's the fun and adventure in that?

On the other hand, yes Al oxide is insoluble in water so guess that would be a good test, just not very exciting. :sleeping: