# Garage doors



## skinne9 (Nov 21, 2009)

Any recommendations for priming this aluminum garage door? The bottom panels basically peeled off in sheets today, I was planning on hitting it with seal_grip alklyd and then peel stop. Weird thing is the other door has no paint failure.

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## skinne9 (Nov 21, 2009)

oops


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## skinne9 (Nov 21, 2009)

Pics

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## Schmidt & Co. (Nov 6, 2008)

I'd use Seal Grip acrylic instead. Obviously you'll need to remove as much of the loose stuff as you can first .


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## MikeCalifornia (Aug 26, 2012)

Yep, no oil!! Saponification is my guess.


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## skinne9 (Nov 21, 2009)

Crap I already hit 1 panel with the rattle can oil, what is Saponification? What would be the best way to remove the sealer I put on?

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## skinne9 (Nov 21, 2009)

Guess I'll sand as much of it off and hit with the acrylic. What do think about the peel stop on top of the seal grip acrylic

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## MikeCalifornia (Aug 26, 2012)

Saponification occurs when the zinc in galvanized metal reacts with an alkyd paint. A soapy film develops and off pops the coating. I would just use a nice DTM, two coats and your done. Problem will be the same issue down the road in a different location though.


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## journeymanPainter (Feb 26, 2014)

MikeCalifornia is right. Another thing to do is sand every square inch of the doors, then hit it with a semititious primer, then your top coats

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## TJ Paint (Jun 18, 2009)

galvanized, use wb

Seriously most any quality wb primer would work, I'd go for one that is good at bonding. The main thing is to get everything very clean. Aluminum has a rust that is hard to see. Cleaning well should remove that.


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## Gough (Nov 24, 2010)

journeymanPainter said:


> MikeCalifornia is right. Another thing to do is sand every square inch of the doors, then hit it with a semititious primer, then your top coats
> 
> Sent from my SGH-T989D using Tapatalk


I know we've been over this before, but in our experience, WB primers substantially outperform *cementitious * primers in these applications.


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## mustangmike3789 (Jun 11, 2011)

skinne9 said:


> Pics
> 
> Sent from my HTC One using PaintTalk.com mobile app


im not so sure that saponification will occur on aluminum. it is normally a reaction over zinc coated or galvanized surfaces and concrete. a reaction occurs from the alkali in the zinc or concrete and the oils in the paint that will form a layer of soap and cause poor adhesion. some modified alkyds are designed to prevent this from happening.
I feel that the reason for the failure on the doors is from osmosis causing osmotic blistering.
if you look at the bottom of the failure in the first photo, you can see a white powdery substance that appears to be aluminum oxide and in the second photo, osmotic blistering. you can remove the blisters and probably find more of the oxide under it.
since salts are hydroscopic, they will attract moisture through the coating and cause the aluminum to corrode, forming blisters from a build up of oxides (salts) and push/burn the coating from the surface.
remove as much of the loose coating and wire brush any bare areas removing the oxides. solvent clean these areas with a non hydrocarbon solvent and paint it with a good acrylic paint.
etching primers can be used for better adhesion on aluminum or pro-cryl primer is another good option.


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## journeymanPainter (Feb 26, 2014)

Gough said:


> I know we've been over this before, but in our experience, WB primers substantially outperform *cementitious * primers in these applications.


Peace of mind is why I would do it.

PS Gough, do you ever sleep?

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## Gough (Nov 24, 2010)

journeymanPainter said:


> Peace of mind is why I would do it.
> 
> PS Gough, do you ever sleep?
> 
> Sent from my SGH-T989D using Tapatalk


Late flight from SoCal....


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## Gough (Nov 24, 2010)

skinne9 said:


> Any recommendations for priming this aluminum garage door? The bottom panels basically peeled off in sheets today, I was planning on hitting it with seal_grip alklyd and then peel stop. Weird thing is the other door has no paint failure.
> 
> Sent from my HTC One using PaintTalk.com mobile app


We probably got started on the wrong foot, since these are aluminum, not galvanized. I think the likely culprit is "aluminum corrosion":


http://www.mpigroup.co.uk/publishing/fitzs-atlas-of-coating-defects/translation/4-coating-defects/


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## Bender (Aug 10, 2008)

I'm going with a simpler explanation. I think it's residue from the factory. Probably machine oil.


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## slinger58 (Feb 11, 2013)

Bender said:


> I'm going with a simpler explanation. I think it's residue from the factory. Probably machine oil.


And I remember the days when you didn't have to be a chemist to be a danged old house painter.


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## skinne9 (Nov 21, 2009)

Thank god there's paint talk for us younger guys

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## slinger58 (Feb 11, 2013)

skinne9 said:


> Thank god there's paint talk for us younger guys
> 
> Sent from my HTC One using PaintTalk.com mobile app


I hear ya, Brother. :jester:


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## journeymanPainter (Feb 26, 2014)

Luckily I have a laundry list of people or places I can go to as well. I usually come back with the same result, just a stop over thinking the prep comment

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## mustangmike3789 (Jun 11, 2011)

journeymanPainter said:


> Luckily I have a laundry list of people or places I can go to as well. I usually come back with the same result, just a stop over thinking the prep comment
> 
> Sent from my SGH-T989D using Tapatalk


I would agree on some of it even though surface prep is the cause of 75% of all paint failures if you eliminate applicator error. Aluminum is a different beast due to its ability to protect itself with oxides that can be difficult to remove or paint over without adhesion problems.


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## Bender (Aug 10, 2008)

mustangmike3789 said:


> I would agree on some of it even though surface prep is the cause of 75% of all paint failures if you eliminate applicator error. Aluminum is a different beast due to its ability to protect itself with oxides that can be difficult to remove or paint over without adhesion problems.


Not trying to argue with you but wouldn't it be more consistent?


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## journeymanPainter (Feb 26, 2014)

Wouldn't what be more consistent?

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## Bender (Aug 10, 2008)

The failure, if it was an oxide problem.


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## skinne9 (Nov 21, 2009)

Yeah looks like I'm the 3rd coat on this door, if I would've been the first would've been cleaned properly and dtm, but primed with seal_grip today and 2 coats of acri-shield and there happy with it. 

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## skinne9 (Nov 21, 2009)

The other door had nothing wrong with it except color fade. That was easy.

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## Gough (Nov 24, 2010)

skinne9 said:


> The other door had nothing wrong with it except color fade. That was easy.
> 
> Sent from my HTC One using PaintTalk.com mobile app


Are both of them exposed to the same conditions year 'round?

Maybe the bad one was made on a Monday or a Friday?


http://skeptics.stackexchange.com/q...uilt-on-a-monday-or-friday-have-lower-quality


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## Bender (Aug 10, 2008)

Gough said:


> Are both of them exposed to the same conditions year 'round?
> 
> 
> 
> http://skeptics.stackexchange.com/q...uilt-on-a-monday-or-friday-have-lower-quality


No, the one on the left goes to Disneyland once a year:whistling2:


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## slinger58 (Feb 11, 2013)

Bender said:


> No, the one on the left goes to Disneyland once a year:whistling2:


That's shameful. LMAO.


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## mustangmike3789 (Jun 11, 2011)

Bender said:


> Not trying to argue with you but wouldn't it be more consistent?


Not necessarily. I do thousands of salt test every year and they can vary in random patterns or stay constant in a single structure just like sweat drops or finger prints.
Aluminum protects itself by passivation by producing a layer of aluminum oxide especially if it is contaminated. If any of these salts are left on the surface, they will attract moisture through the coating since organic coatings are permeable and allow moisture to pass through them. Osmosis is a natural balance when salt is present. If a certain level of salt is left on the surface under the coating, it will self balance by building the balance on the outside of the coating also and continue to build causing the blisters. Salts will continue to pull moisture from the air just like a fine steakhouse dry aging steaks with salt blocks in their cooler.
Passivation happens almost immediately on aluminum and stainless steel. You can see this happen on some stainless as you drag your fingers across the surface of stainless and watch the trails on the steel chase your fingers accross the surface and blend back with no trace of the smears. 
If this were caused by machine oils, I dont think that it would have held up very long at all, just like trying to protect an area not to be painted by spraying it with WD-40. Some paints will stay over the oiled surface without any signs but poor adhesion but others will wrinkle and pull away or fisheye. Also, it looks like a heavy build of oxidation in the photo and the blisters are not likely caused by oils on the surface.


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## mustangmike3789 (Jun 11, 2011)

slinger58 said:


> And I remember the days when you didn't have to be a chemist to be a danged old house painter.


Im not a chemist or an old house painter so your still good.


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## Bender (Aug 10, 2008)

mustangmike3789 said:


> Not necessarily. I do thousands of salt test every year and they can vary in random patterns or stay constant in a single structure just like sweat drops or finger prints.
> Aluminum protects itself by passivation by producing a layer of aluminum oxide especially if it is contaminated. If any of these salts are left on the surface, they will attract moisture through the coating since organic coatings are permeable and allow moisture to pass through them. Osmosis is a natural balance when salt is present. If a certain level of salt is left on the surface under the coating, it will self balance by building the balance on the outside of the coating also and continue to build causing the blisters. Salts will continue to pull moisture from the air just like a fine steakhouse dry aging steaks with salt blocks in their cooler.
> Passivation happens almost immediately on aluminum and stainless steel. You can see this happen on some stainless as you drag your fingers across the surface of stainless and watch the trails on the steel chase your fingers accross the surface and blend back with no trace of the smears.
> If this were caused by machine oils, I dont think that it would have held up very long at all, just like trying to protect an area not to be painted by spraying it with WD-40. Some paints will stay over the oiled surface without any signs but poor adhesion but others will wrinkle and pull away or fisheye. Also, it looks like a heavy build of oxidation in the photo and the blisters are not likely caused by oils on the surface.


Very interesting.
Thank you


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## skinne9 (Nov 21, 2009)

Gough said:


> Are both of them exposed to the same conditions year 'round?
> 
> Maybe the bad one was made on a Monday or a Friday?
> 
> ...


Yep same conditions.

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## SemiproJohn (Jul 29, 2013)

mustangmike3789 said:


> Not necessarily. I do thousands of salt test every year and they can vary in random patterns or stay constant in a single structure just like sweat drops or finger prints.
> Aluminum protects itself by passivation by producing a layer of aluminum oxide especially if it is contaminated. If any of these salts are left on the surface, they will attract moisture through the coating since organic coatings are permeable and allow moisture to pass through them. Osmosis is a natural balance when salt is present. If a certain level of salt is left on the surface under the coating, it will self balance by building the balance on the outside of the coating also and continue to build causing the blisters. Salts will continue to pull moisture from the air just like a fine steakhouse dry aging steaks with salt blocks in their cooler.
> Passivation happens almost immediately on aluminum and stainless steel. You can see this happen on some stainless as you drag your fingers across the surface of stainless and watch the trails on the steel chase your fingers accross the surface and blend back with no trace of the smears.
> If this were caused by machine oils, I dont think that it would have held up very long at all, just like trying to protect an area not to be painted by spraying it with WD-40. Some paints will stay over the oiled surface without any signs but poor adhesion but others will wrinkle and pull away or fisheye. Also, it looks like a heavy build of oxidation in the photo and the blisters are not likely caused by oils on the surface.



Very interesting information. Thanks for the explanation.


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