Help me understand this
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TuckerTavern
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Help me understand this
This is a new sash that we got 2 or 3 years ago. We primed with Sherwin Williams recommended primer and then 2 coats of SW exterior paint. Why is this happening?
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phil
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Re: Help me understand this
was the wood dry right through when you painted it? maybe the wood was dry on the surface but had high moisture content, and then got warm and the "steam" found a way out? Just a guess..
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TuckerTavern
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Re: Help me understand this
phil wrote:was the wood dry right through when you painted it? maybe the wood was dry on the surface but had high moisture content, and then got warm and the "steam" found a way out? Just a guess..
I mean, I think so? It certainly felt dry and sat in our parlor for several weeks before we began painting it. I'm so put out, that was pricey paint!
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Casey
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Re: Help me understand this
what type of wood? What type of primer?
The artist formerly known as Sombreuil
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1918ColonialRevival
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Re: Help me understand this
It looks like a moisture issue. Like it was trapped underneath in the wood and worked its way out, splitting and lifting the paint with it.
Re: Help me understand this
it could be a moisture issue but if it sat in your warm dry house for weeks BEFORE priming and painting, that shouldn't be the problem...is it pine? could be pitch leeching out...did you prime with oil primer? perhaps you've already done this but I would send a photo to the sash maker and see what they think...
sorry you're having this issue...yup, that's a drag...
....jade
sorry you're having this issue...yup, that's a drag...
....jade
Re: Help me understand this
Do you have any 'better' pic(s)? It's hard to tell if you have cracking as well as staining, etc.
New sash, check. Dry when painted, check...has this been outdoors? How long since it was painted?
If the paint is NOT cracked, it does look like pitch coming out, just from a distance.
SW exterior paint...was it DURATION? We need the brand of primer/paint, please. Oil vs. alkyd is important.
Another thought ....could there have been ANYTHING on the wood prior to painting? We (painters) usually 'rough up' a surface (a relative term!) with some sandpaper before priming....a manufactured piece like that may call for 150 or 180 grit...just to break any "mill glaze" (debatable, but still a good idea) and hopefully take out any foreign *stuff* that may be on the wood. You won't see any sanding scratches if you use 150 grit or higher, prime, and 2 topcoats, and it goes without saying that we NEVER touch glass with sandpaper
Will check back for more pics...
New sash, check. Dry when painted, check...has this been outdoors? How long since it was painted?
If the paint is NOT cracked, it does look like pitch coming out, just from a distance.
SW exterior paint...was it DURATION? We need the brand of primer/paint, please. Oil vs. alkyd is important.
Another thought ....could there have been ANYTHING on the wood prior to painting? We (painters) usually 'rough up' a surface (a relative term!) with some sandpaper before priming....a manufactured piece like that may call for 150 or 180 grit...just to break any "mill glaze" (debatable, but still a good idea) and hopefully take out any foreign *stuff* that may be on the wood. You won't see any sanding scratches if you use 150 grit or higher, prime, and 2 topcoats, and it goes without saying that we NEVER touch glass with sandpaper
Will check back for more pics...
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TuckerTavern
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Re: Help me understand this
If we don't get rain I'll try to get better pictures tomorrow and the other information people asked for.
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phil
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Re: Help me understand this
If you buy wood that is freshly milled, it has a high moisture content from when it was a tree. then the normal process is to sticker and stack it to let dry. the dry time could vary depending on the environment. You can use fans or heat to help and a lot of wood is kiln dried. the rule of thumb is an inch a year so if they were 2" thick planks they would take two years but it can vary. the tree might be more wet if cut in the fall compared to summer. typically you will see the boards do some bending and twisting and then the next step is to straighten them before use by jointing and thickness planing, then they can be used. this dry process is normally a matter of months or years unless it is forced.
even when dried if you split those boards into strips then you'd see some warpage from the wood normalizing. wood has internal stresses and after you ripped a board into strips you may notice them moving bending curling and twisting until they find their happy place again. this happens because the wood has had some of the stresses removed where you cut them.. wood normally has some stresses within itself. so a woodworker would rip the lumber to his rough size , let this twisting happen and then joint and plane, otherwise his perfectly straight boards would normalize and go twisty even after it is processed into straight and supposedly usable lumber.
If you skip the drying step, or take it when the moisture hasn't dropped enough the wood will appear pretty normal but since it hasn't been allowed to and you can make things out of it, but then what happens is warpage occurs as the wood is still normalizing.
if you take a board and put it in the rain for a few days it gets wet on the outside and if you bring it in a few days it will be dry to the touch, but inside the wood, that is different and it takes time. firewood is best if it is a year or two old.
also if your dry wood is not stored in a place with suitable humidity it is going to change when it's environment changes.. so your windows could be made perfectly but then stored in a warehouse that had a leaky roof for example.. then they would suck up the humidity from around them.
If the tree is knotty or some species just twist more. Generally if it is a big tree like the trunk of a giant fir, then the wood has less stress, if the grain is figurative or if the tree had a lot of branches, then there is more uneven stress thus more warpage.
So this is about the paint and maybe that was too many words
but I wanted to make the point about the wood's moisture content , the surface moisture is different than the internal moisture content. the internal content might not change much over a few weeks but if the moisture is in there and you seal it with paint , it'll find its way out and look something like what you have.
a quick check is usually to cut a piece and then touch the endgrain to see if it feels damp, if it does feel damp then it isn't dry enough.. that might not matter on a fence so much as a piece of furniture.
I wouldn't think a window manufacturer would use wood that hadn't acclimatized properly because they would know about warpage and that is their enemy.. a warped window will be rejected.
it could still definitely be a possibility. So a question. Did you notice any warpage of them? because that might be another sign if they used lumber that was too green. If it wasn't that, then that maybe it just wasn't good paint or maybe it didn't soak in right or something. Was the painting done on a hot sunny day? maybe it dried before it had a chance to really penetrate?
another cause of poor adhesion is "mill glaze" when boards are put through the blades of jointers and thickness planers the blades sort of beat the oard and leave a sort of hardened smooth surface.. You can sand or even pressurewash or just use the wood and allow the hunidity and rain to remove the mill glaze but if you go straight to painting it wont' stick as well because the wood is too smooth to hold onto the paint well.. so if you build a set of stairs with fresh wood from home depot you are often best to not paint them for a while so that they dry out and "fuzz up a bit" then the paint sticks better.
Phil
even when dried if you split those boards into strips then you'd see some warpage from the wood normalizing. wood has internal stresses and after you ripped a board into strips you may notice them moving bending curling and twisting until they find their happy place again. this happens because the wood has had some of the stresses removed where you cut them.. wood normally has some stresses within itself. so a woodworker would rip the lumber to his rough size , let this twisting happen and then joint and plane, otherwise his perfectly straight boards would normalize and go twisty even after it is processed into straight and supposedly usable lumber.
If you skip the drying step, or take it when the moisture hasn't dropped enough the wood will appear pretty normal but since it hasn't been allowed to and you can make things out of it, but then what happens is warpage occurs as the wood is still normalizing.
if you take a board and put it in the rain for a few days it gets wet on the outside and if you bring it in a few days it will be dry to the touch, but inside the wood, that is different and it takes time. firewood is best if it is a year or two old.
also if your dry wood is not stored in a place with suitable humidity it is going to change when it's environment changes.. so your windows could be made perfectly but then stored in a warehouse that had a leaky roof for example.. then they would suck up the humidity from around them.
If the tree is knotty or some species just twist more. Generally if it is a big tree like the trunk of a giant fir, then the wood has less stress, if the grain is figurative or if the tree had a lot of branches, then there is more uneven stress thus more warpage.
So this is about the paint and maybe that was too many words
but I wanted to make the point about the wood's moisture content , the surface moisture is different than the internal moisture content. the internal content might not change much over a few weeks but if the moisture is in there and you seal it with paint , it'll find its way out and look something like what you have. a quick check is usually to cut a piece and then touch the endgrain to see if it feels damp, if it does feel damp then it isn't dry enough.. that might not matter on a fence so much as a piece of furniture.
I wouldn't think a window manufacturer would use wood that hadn't acclimatized properly because they would know about warpage and that is their enemy.. a warped window will be rejected.
it could still definitely be a possibility. So a question. Did you notice any warpage of them? because that might be another sign if they used lumber that was too green. If it wasn't that, then that maybe it just wasn't good paint or maybe it didn't soak in right or something. Was the painting done on a hot sunny day? maybe it dried before it had a chance to really penetrate?
another cause of poor adhesion is "mill glaze" when boards are put through the blades of jointers and thickness planers the blades sort of beat the oard and leave a sort of hardened smooth surface.. You can sand or even pressurewash or just use the wood and allow the hunidity and rain to remove the mill glaze but if you go straight to painting it wont' stick as well because the wood is too smooth to hold onto the paint well.. so if you build a set of stairs with fresh wood from home depot you are often best to not paint them for a while so that they dry out and "fuzz up a bit" then the paint sticks better.
Phil
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TuckerTavern
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Re: Help me understand this
OK, I used a latex primer and the paint was Resiliance. I went by the paint brand that the sash maker suggested and followed SW's recommendation for primer. I didn't notice any warping or anything amiss really. There's no mildew, just areas of paint loss on most of the surfaces but especially on the bottom rail. The sash is pine, I believe.
