Corroded fasteners in aluminum lania

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Old 02-08-16, 05:09 PM
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Corroded fasteners in aluminum lania

Well guys I have been slopping bonder and SW Super Paint and Emulsa bond on my SW Florida stucco house for 6 or 7 weeks now and getting to the lanai area. I will never attempt to brush/roll perforated aluminum soffit again, what a pain

The lanai is 28 years old and made of brown structural aluminum, no idea what the finish is but it is factory. The finish is faded, discolored and looks bad.

The issue is the fasteners, small hex head screws which I assume are steel. The screw heads are rusty and have caused corrosion around them. I have found a Povia latex paint that is supposedly for lanai and pool enclosures.

I have been warned not to try and remove the screws as they will snap:NO NO NO:

I have done several searches and not sure how to treat the screws and corrosion any input on this would be greatly appreciated If it were smaller I would replace it, but it is 40X8 feet with 2 doors.

I am installing a new aluminum frame door and am going to use aluminum pull rivits
Jim SW FL
 
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Old 02-08-16, 06:39 PM
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I've had good luck treating small areas of rust like that with rust converter:

GEMPLER'S&reg Rust Converter One Quart | GEMPLER'S

You just remove any really loose flaky rust, paint the converter on, wait until it does it thing and dries, and then paint with latex paint.

I used it on my Bilco door when it started to rust, and it was easy to use and so far (couple of years) the treated area is still holding up.

Before trying the converter, I would remove loose rust, prime with rusty metal primer, and then paint, and the area would always start to rust again quickly.
 
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Old 02-08-16, 07:17 PM
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A rust converter would take care of screw heads leaving the corrosion around them. Any idea on the corrosion?

Thanks for the response always greatly appreciated. Jim
 
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Old 02-09-16, 02:37 AM
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I've had good luck and not so good luck with rust converters

I'd clean them up the best I could, apply the rust converter [or not] apply a solvent base primer over the screws and corrosion and then apply the SuperPaint. That should stop any further corrosion.
 
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Old 02-09-16, 06:15 AM
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Thanks for the response! I have had so so results with rust converters except Por 15. The only study I have found says that Rust Oleum rust reformer is best, they did not test all converters.

https://ncptt.nps.gov/blog/comparati...st-converters/

My go to paint for rust is Rust Oleum however it never seems to dry. I am thinking the Sherwin Williams brand rattle can rust control primer?

If I were doing this new I would use aluminum rivets, the steel screws are not the answer, little disclaimer I have a pneumatic riveter and a large selection of rivets.
 
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Old 02-09-16, 06:54 AM
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The corrosion around the screws (as opposed to the rust) is most likely from the contact of dissimilar metals (steel and aluminum). If you can't replace the steel fasteners (and I agree, they are likely to snap off) then the best you can do at this point is to keep water away from the junction of the two so there is no electrolyte to facilitate the galvanic corrosion. You can sand or wire brush the existing corrosion to improve the appearance and enhance the adhesion of the paint, but good coating of paint will be the best action to prevent further corrosion.

OTOH, if the screws are badly rusted, one has to wonder how long it will be before they fail. Is there room to install an aluminum rivet next to the screws and then try to remove the screws? If the heads snap off you are really no worse off at that point....
 
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Old 02-09-16, 09:18 AM
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Screws fail? Great, now I have something else to consider redoing anything on this will be very time consuming, there are a minimum of 600 screws.

I think I will wire brush and prime, then hope I pass before they fail, keep the hurricane insurance paid or sell the house.
Jim
 
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Old 02-09-16, 10:16 AM
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If they just have surface rust, no worry. If the heads are crumbling...
 
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Old 02-09-16, 06:35 PM
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I had a thought OH OH! I could disassemble this thing cut the corroded ends off each piece, paint and reassemble, then I would only have to buy a few pieces.

Somebody stop me I need help Jim
 
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Old 02-09-16, 07:55 PM
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Inside every small project is a big project waiting to slug you over the head and take all your money and time....
 
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Old 02-10-16, 04:13 AM
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More projects than not tend to grow before you get done
Sometimes you need to let the budget or time constraints win
 
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