# Storm Door Traps Heat



## Betheweb (Jul 26, 2016)

This is kind of a cross post from the DIY site, but I thought maybe it would make more sense here. 

I painted an entry door for a customer. The paint all blistered up apparently because of the sun and the storm door trapped the heat. Should I be using some special high heat paint in this situation? Painting a door with a storm door in front of it seems like a pretty simple thing. Is there a technique you use to make it work or do you just turn down those jobs?


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## Betheweb (Jul 26, 2016)

It has warts.


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## journeymanPainter (Feb 26, 2014)

Betheweb said:


> This is kind of a cross post from the DIY site, but I thought maybe it would make more sense here.
> 
> I painted an entry door for a customer. The paint all blistered up apparently because of the sun and the storm door trapped the heat. Should I be using some special high heat paint in this situation? Painting a door with a storm door in front of it seems like a pretty simple thing. Is there a technique you use to make it work or do you just turn down those jobs?


The film is forming before the solvents can evaporate.
Sand the door down, mud and prime as required, either paint the door after sunset, remove the door and paint in a shaded area, or create temporary shade

Sent from my SM-G903W using Tapatalk


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## Epoxy Pro (Oct 7, 2012)

2 choices really. 1 leave storm door cracked open until paint dries. 2, if storm door has a screen crack it open.

Storm doors with glass will heat the door up fast and cause this. Sand it down and repaint. 

Storm doors are nice but can cause damage.


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## Epoxy Pro (Oct 7, 2012)

More or less you need airflow between the storm door and entry door.


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## Betheweb (Jul 26, 2016)

Weird thing, though is I painted it in May and she says it was fine all summer. It only blistered in the fall.


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## NACE (May 16, 2008)

Was the door previously painted? If not, what did you clean it with and what did you prime it with?


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## Epoxy Pro (Oct 7, 2012)

Metal, wood or fiberglass door?


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## PACman (Oct 24, 2014)

New door or repaint? One coat of superduperhyper paint and primer in one or two?


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## Gough (Nov 24, 2010)

Betheweb said:


> Weird thing, though is I painted it in May and she says it was fine all summer. It only blistered in the fall.


What is the exposure of the door, N,S,E,or W? How much, if any, roof overhang?
Later in the season, with the sun lower in the sky, some surfaces end up heating up more than they do in the height of summer.

For more than you probably want to know, you can read up on Lambert's Cosine Law:

http://thesolarbucket.blogspot.com/2014/01/lamberts-cosine-law.html


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## CApainter (Jun 29, 2007)

What product did you use? If it can't tolerate the heat load during summer, there is a possibility the film was compromised. It may have taken the cooler fall weather to begin the expansion and contraction of the coating due to moisture permeation through the waterborne film matrix.


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## Betheweb (Jul 26, 2016)

That's a good point. This was just a color change. It was previously painted and the old paint was not in bad shape. So the last guy who painted it was able to make it work. I put on 3 coats of SW Resilience gloss. I wasn't getting great coverage with that red color. I remember I had finished up the other work, but I had to make a special trip back to do another coat on the door. There is a metal awning over the door, so that gives it some protection. I have to read that cosine stuff, but Gough makes an interesting point about the angle. the house faces southwest.


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## CApainter (Jun 29, 2007)

The TDS requires a 24 hr. dry time before recoating. Did you wait that long?

Permeability comparison:

SW Resilience Acrylic Gloss-16.3 Perms (low permeability)

BM Aura Exterior Semi Gloss acrylic-46 Perms (higher permeability)

This may explain the need to allow the SWR to dry overnight in order to remove solvents that could be trapped in a low permeable film if second coated too soon. In comparison, the BM allows 4 hr. recoat.


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## Betheweb (Jul 26, 2016)

Very cool. I never gave much thought to actually quantifying the permeability of paint and doing something useful with it. It's always been kind of a vague concept in my brain. 

I remember I was doing some other interior work. The third coat was definitely a different day, but I likely might have tried to squeeze the first two coats into one day. When I go to fix it, it'll be interesting to see if it is red or blue under those bubbles.


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## Betheweb (Jul 26, 2016)

But, on the other hand, SW Multi-Purpose primer has an even lower permeability and you can top coat it in an hour...


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## chrisn (Jul 15, 2007)

CApainter said:


> What product did you use? If it can't tolerate the heat load during summer, there is a possibility the film was compromised. It may have taken the cooler fall weather to begin the expansion and contraction of the coating due to moisture permeation through the waterborne film matrix.


 
Say what?:laughing::blink::blink:

waterborne film matrix?


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## CApainter (Jun 29, 2007)

Betheweb said:


> But, on the other hand, SW Multi-Purpose primer has an even lower permeability and you can top coat it in an hour...


Given that the SW Resilience and Multi purpose primer do share similar VOC g/l, DFT, perms, and SBV%, the only thing I can think of, that may impact the speed of their film forming coalescing properties, is that one is an Acrylic resin while the other is a latex resin base. Also, different vehicles may be used in one product verses the other. The MSDS didn't seem to describe the vehicle solvents for the multi primer.


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## CApainter (Jun 29, 2007)

chrisn said:


> Say what?:laughing::blink::blink:
> 
> waterborne film matrix?


I'm just trying to seem relevant amongst the PT Millenials (still can't spell it correctly), even though I know they look at us Boomers as wash ups. But it gives me purpose.


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## PACman (Oct 24, 2014)

dang am i stuck in the matrix again?


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