This isn't directly case-related, but I suppose it's more likely to be used for making cases than anything else.
Sometimes you want a panel made of a particular material, but it would have to be so thick to acheive the required stiffness or strength that it would be too expensive, or too heavy, or just not available at all. What do you do? Make a sandwich!
In this case I wanted a long panel made of carbon fibre, but it would cost a lot to buy it in sufficient thickness. I therefore used two thin sheets with a core made out of aluminium honeycomb. I hadn't used honeycomb before, so I might not have done this quite right, but it worked.
Here are the materials I used:
Underneath you can see the honeycomb. It's 20mm thick with cells 19mm in diameter, which will result in very stiff panels, and probably strong enough to stand on. It came squished flat, and I expanded it by simply pulling it with my hands. That didn't give very even results - the proper way to do it is to use something like two strips of wood with nails at regular intervals to pull it apart evenly.
Above that is the carbon, which can be very thin here - I used 1mm, but 0.5mm would be fine for most purposes.
Standing on top is the two-part epoxy used to bond it all together (any epoxy will do).
To start, I cut the carbon into two equal sheets, one for each side, and trimmed a bit of honeycomb slightly larger. Then I mixed up enough epoxy to cover the panel to a depth of about 0.5mm (as I said, I haven't done this before, so that might not be an optimum amount), placed the honeycomb on top, then placed a heavy sheet of wood on top to hold it down (making sure the wood and the worktop underneath were perfectly flat).
After waiting about 7 hours for the epoxy to cure, I did the same for the other side, and waited another 7 hours...
I then trimmed the excess aluminium so the edge was flush all the way around. If the panel edge was not exposed then that would be sufficient, but for my purposes the edges were a little too sharp for comfort, so I squished them in a bit too, as you can see in the following photo:
It's a bit hard to see due to it being transparent, but the epoxy has been sucked up by surface tension to form reasonable-looking fillets.
And that's it. A panel like that is stiff like a solid peice of wood, but a fraction of the weight. Other materials can be used to reduce cost, or for different physical properties, or just to look different, e.g. glass fibre or aluminium for the skin with closed-cell foam, expanded polystyrene or wood for the core.
Sometimes you want a panel made of a particular material, but it would have to be so thick to acheive the required stiffness or strength that it would be too expensive, or too heavy, or just not available at all. What do you do? Make a sandwich!
In this case I wanted a long panel made of carbon fibre, but it would cost a lot to buy it in sufficient thickness. I therefore used two thin sheets with a core made out of aluminium honeycomb. I hadn't used honeycomb before, so I might not have done this quite right, but it worked.
Here are the materials I used:
Underneath you can see the honeycomb. It's 20mm thick with cells 19mm in diameter, which will result in very stiff panels, and probably strong enough to stand on. It came squished flat, and I expanded it by simply pulling it with my hands. That didn't give very even results - the proper way to do it is to use something like two strips of wood with nails at regular intervals to pull it apart evenly.
Above that is the carbon, which can be very thin here - I used 1mm, but 0.5mm would be fine for most purposes.
Standing on top is the two-part epoxy used to bond it all together (any epoxy will do).
To start, I cut the carbon into two equal sheets, one for each side, and trimmed a bit of honeycomb slightly larger. Then I mixed up enough epoxy to cover the panel to a depth of about 0.5mm (as I said, I haven't done this before, so that might not be an optimum amount), placed the honeycomb on top, then placed a heavy sheet of wood on top to hold it down (making sure the wood and the worktop underneath were perfectly flat).
After waiting about 7 hours for the epoxy to cure, I did the same for the other side, and waited another 7 hours...
I then trimmed the excess aluminium so the edge was flush all the way around. If the panel edge was not exposed then that would be sufficient, but for my purposes the edges were a little too sharp for comfort, so I squished them in a bit too, as you can see in the following photo:
It's a bit hard to see due to it being transparent, but the epoxy has been sucked up by surface tension to form reasonable-looking fillets.
And that's it. A panel like that is stiff like a solid peice of wood, but a fraction of the weight. Other materials can be used to reduce cost, or for different physical properties, or just to look different, e.g. glass fibre or aluminium for the skin with closed-cell foam, expanded polystyrene or wood for the core.
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