Louisd75
Adventurer
@rruff
I was doing a little light reading of "Sandwich Structural Composites: Theory and Practice" (ISBN 978-0367441722, can't link directly to the Amazon page). They do a good breakdown of the common core materials early on in the text. Regarding PVC, "PVC foam contains carbon dioxide gas under pressure, so outgassing can occur at elevated temperatures over time -- that is, the gas diffuses from the closed cells and migrates to voids or unbounded areas in the laminate. In some instances, outgassing has been blamed for delamination and blistering in the sandwich construction, especially in parts made at elevated cure temperatures or finished in dark colors and in direct exposure to the sun." It only mentions that as an issue for PVC cores so far, I haven't read up on XPS yet but I'm kind of jumping around the book. Light colors *may* be enough to avoid the issue.
That said, Total Composites and Fiber-Tech also discuss the temperature issue in related to dark panel colors. TC only does one core material and white panels (though at least *some* of their rigs have black decals applied to the panels). Fiber-Tech's warranty fine print states "This warranty is void upon application of dark colors to the panel" but doesn't differentiate between the different core materials, it's a blanket warranty statement. These two cases make me wonder if it's potentially an epoxy/resin/adhesive issue as well, but I'm not that far into the book
Personally, I've been going back and forth for a while now for building vs buying my panels. I'm still a little ways off from needing to move on the choice, but I read through the build threads and one thing that sticks out is the amount of time and labor involved. I'm all for saving some coin, but my time off is precious enough that farming the work out to someone who does it for a living may be better for myself and my project.
On the topic of the book, it's definitely interesting though it's also a bit technical and dry. I'm pretty sure it's meant to be a text book for a college level engineering course. One of the takeaways that I'm finding is that you can ballpark core and skin properties to come up with general statements, but there are so many variables that you really need to test each formulation, perhaps to the point of each batch, to know the actual panel properties.
I was doing a little light reading of "Sandwich Structural Composites: Theory and Practice" (ISBN 978-0367441722, can't link directly to the Amazon page). They do a good breakdown of the common core materials early on in the text. Regarding PVC, "PVC foam contains carbon dioxide gas under pressure, so outgassing can occur at elevated temperatures over time -- that is, the gas diffuses from the closed cells and migrates to voids or unbounded areas in the laminate. In some instances, outgassing has been blamed for delamination and blistering in the sandwich construction, especially in parts made at elevated cure temperatures or finished in dark colors and in direct exposure to the sun." It only mentions that as an issue for PVC cores so far, I haven't read up on XPS yet but I'm kind of jumping around the book. Light colors *may* be enough to avoid the issue.
That said, Total Composites and Fiber-Tech also discuss the temperature issue in related to dark panel colors. TC only does one core material and white panels (though at least *some* of their rigs have black decals applied to the panels). Fiber-Tech's warranty fine print states "This warranty is void upon application of dark colors to the panel" but doesn't differentiate between the different core materials, it's a blanket warranty statement. These two cases make me wonder if it's potentially an epoxy/resin/adhesive issue as well, but I'm not that far into the book
Personally, I've been going back and forth for a while now for building vs buying my panels. I'm still a little ways off from needing to move on the choice, but I read through the build threads and one thing that sticks out is the amount of time and labor involved. I'm all for saving some coin, but my time off is precious enough that farming the work out to someone who does it for a living may be better for myself and my project.
On the topic of the book, it's definitely interesting though it's also a bit technical and dry. I'm pretty sure it's meant to be a text book for a college level engineering course. One of the takeaways that I'm finding is that you can ballpark core and skin properties to come up with general statements, but there are so many variables that you really need to test each formulation, perhaps to the point of each batch, to know the actual panel properties.
