Could you build a re-inforced box-girder like structure out of rigid polystyrene foam by sandwiching it with carbon fiber tape + epoxy?
Carbon-fiber plated foam core is filthy expensive, but raw polystyrene board and carbon fiber tape are pretty cheap individually.
Maybe any light aircraft/surfing people would know.
The buckling mode involves squashing the filler, which is why surfboards and stuff are (classically) made of fibreglass over balsa with the grain oriented along the shortest axis of the board--it's far stronger in that direction.
You wouldn't have that advantage with foam, but it might work OK if the foam were strong enough. Of course, "strong" and 'styrofoam' aren't usually used together. ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Polyamide foam (nylon) is used for radomes on the Eurofighter and for the core of the tailfin of Airbus planes. I have some samples which I obtained for use as an "invisible" substrate when prototyping microwave antenna designs (a trick I learned from a Nokia paper).
John
Yeah, I guess the "reinforced" foam would be much stronger in the compression-direction. Might need to use carbon-fiber rods or something, like rebar.
It's nothing important I just want a lightweight custom modular table for my model choo-choos, and don't really own any woodworking equipment.
It's fun to think about a table incorporating carbon fiber, anything's possible with enough $$$ thrown at the problem even a table made completely of composite plate. Best guess for the price on that would be into the thousands for a 4x8.
I'll probably contract this job out, it's not a large one and the custom benchwork guys (they exist!) could likely use the money. I much prefer doing wiring and working on models I can fit on a small worktable than looking like I'm re-framing my house.
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I'm not sure carbon fiber would bring a lot to the party other than cool lo oks. They make kayaks out of layered plastics with a weaker and lighter pl astic as a core and a sturdier, but heavier plastic on the outside for stre ngth. I thought that fiberglass over foam was a common technique for thing s like surf and body boards.
I've seen hollow plastic tables which won't hold much weight. They flex te rribly. Giving them a core and stronger covering would certainly be strong er, but less flexible. When the limit is reached it would just fold. Look at the construction of a sumac tree. The core is all pith with the only r eal strength in the outer section.
The concept is doable, but I don't think tape would work. The point is for the outer layer to have compression strength and the inner layer provides spacing to provide gain, i.e. leverage.
A layer of plywood, even just 1/4 inch with a lattice of 1x4 underneath, on edge will provide lots of strength. Secure 1x4 to the edges as a frame an d you've got a nice train board. My dad made something like that when we w ere kids.
-- Rick C. + Get 1,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
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looks. They make kayaks out of layered plastics with a weaker and lighter plastic as a core and a sturdier, but heavier plastic on the outside for st rength. I thought that fiberglass over foam was a common technique for thi ngs like surf and body boards.
terribly. Giving them a core and stronger covering would certainly be stro nger, but less flexible. When the limit is reached it would just fold. Lo ok at the construction of a sumac tree. The core is all pith with the only real strength in the outer section.
or the outer layer to have compression strength and the inner layer provide s spacing to provide gain, i.e. leverage.
on edge will provide lots of strength. Secure 1x4 to the edges as a frame and you've got a nice train board. My dad made something like that when we were kids.
and that is basically what you get in a ikea table top or if you want to fe el like a hacker a hollow core interior door
Some of the construction foam insulation boards are stiff enough that you can pour concrete against 'em without crushing, but there's no long-stick internal structure in a foam (more-or-less, it's bubbles packed together) so the compressive strength is compromised: all the bubble walls form pre-kinked columns, with poor performance regardless of materials used.
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r nl looks. They make kayaks out of layered plastics with a weaker and lighte r plastic as a core and a sturdier, but heavier plastic on the outside for strength. I thought that fiberglass over foam was a common technique for t hings like surf and body boards.
x terribly. Giving them a core and stronger covering would certainly be st ronger, but less flexible. When the limit is reached it would just fold. Look at the construction of a sumac tree. The core is all pith with the on ly real strength in the outer section.
for the outer layer to have compression strength and the inner layer provi des spacing to provide gain, i.e. leverage.
, on edge will provide lots of strength. Secure 1x4 to the edges as a fram e and you've got a nice train board. My dad made something like that when we were kids.
feel like a hacker a hollow core interior door
For a train table, a couple of hollow core doors would do pretty well. The y are usually truly hollow however and so have only the strength of the thi n door material. Put anything remotely heavy on it and the surface will bo w easily. It's also very easily dented. Ideal would be a foam core, thin laminate for looks and fiberglass surface for toughness.
I have a shallow desk made up from two saw horses, two 1x4 and a hollow cor e door. It was at the lake house so a girl friend could work from there in stead of home. People like being right next to the water. I may use it fo r a work space soon.
-- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
I don't suppose they make doors 14" deep and 10' long...
Yes. I had a racing catamaran made that way, fibreglass sandwich. Fully rigged 14' cat which weighed only 50kg...
My neighbour at the time was a retired composite plastics engineer who had invented many fabrication techniques, and he pointed out that the glass foam sandwich of the same weight as a thinner carbon-reinforced glass sheet had about the same strength but much greater toughness. You could almost poke your finger through the CRP but it was difficult to penetrate the glass sandwich without a large hammer.
So the layered construction does have advantages.
I've seen Nomex honeycomb being used as sandwich filler too.
CH
Hollow doors, or that Ikea hollow tabletop "Linnmon" which is basically the same thing, but with less wood at the edges because no hinges or latches are needed.
-- Jasen.
If you have a flat spot, you can lay out a sheet of plywood, apply Liquid Nails to it, and put a sheet of foam and another layer of adhesive, then another sheet of plywood. 4 x 8 foot foam and thin plywood are widely available construction materials.
Just be sure to test the glue against a sample of the foam, it might dissolve.
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ool looks. They make kayaks out of layered plastics with a weaker and ligh ter plastic as a core and a sturdier, but heavier plastic on the outside fo r strength. I thought that fiberglass over foam was a common technique for things like surf and body boards.
lex terribly. Giving them a core and stronger covering would certainly be stronger, but less flexible. When the limit is reached it would just fold. Look at the construction of a sumac tree. The core is all pith with the only real strength in the outer section.
is for the outer layer to have compression strength and the inner layer pro vides spacing to provide gain, i.e. leverage.
th, on edge will provide lots of strength. Secure 1x4 to the edges as a fr ame and you've got a nice train board. My dad made something like that whe n we were kids.
to feel like a hacker a hollow core interior door
They are usually truly hollow however and so have only the strength of the thin door material. Put anything remotely heavy on it and the surface wil l bow easily. It's also very easily dented. Ideal would be a foam core, t hin laminate for looks and fiberglass surface for toughness.
core door. It was at the lake house so a girl friend could work from ther e instead of home. People like being right next to the water. I may use i t for a work space soon.
split one of half and glue in a piece of trim will be close
What kind of strength are you looking for? Weight? Carbon Fibre gives you some advantage in strength/weight but if weight is not a big issue normal fiber glass would work and is a lot cheaper.
Most composite books have a diagram that shows a 2t core thickness gives you +6 stiffness, +2.5 strength at +.03 weight.
4t is +36, +8.2 at +.06 weight. That's for a solid foam core. Unless you really need the weight savings I would not recommend honeycomb core unless you have done it before or want to learn. The foam core wont have much compressive strength. You have to pay special attention to bolts going through the core. Connector loading has to be carefully considered.The fiber is gonna have most strength in tension. Lots of info on the web.
-- Chisolm Texas-American Building composite experimental aircraft.
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cool looks. They make kayaks out of layered plastics with a weaker and li ghter plastic as a core and a sturdier, but heavier plastic on the outside for strength. I thought that fiberglass over foam was a common technique f or things like surf and body boards.
flex terribly. Giving them a core and stronger covering would certainly b e stronger, but less flexible. When the limit is reached it would just fol d. Look at the construction of a sumac tree. The core is all pith with th e only real strength in the outer section.
t is for the outer layer to have compression strength and the inner layer p rovides spacing to provide gain, i.e. leverage.
eath, on edge will provide lots of strength. Secure 1x4 to the edges as a frame and you've got a nice train board. My dad made something like that w hen we were kids.
t to feel like a hacker a hollow core interior door
. They are usually truly hollow however and so have only the strength of t he thin door material. Put anything remotely heavy on it and the surface w ill bow easily. It's also very easily dented. Ideal would be a foam core, thin laminate for looks and fiberglass surface for toughness.
ow core door. It was at the lake house so a girl friend could work from th ere instead of home. People like being right next to the water. I may use it for a work space soon.
-shelves/
When I was a kid, my dad made a desk for me from hollow core doors, I think it took two, one for the top and one for the four verticals. A few pieces of wood across the bottoms and some rails across the front, add some home made drawers and presto! A complete desk with drawers. It even had suppor ts under the center drawer to store a drafting board (commonly used in thos e days). I've kept it all these years. The only issue was the drawers wer e made a bit too snug and as the wood swells from humidity they stick prett y badly. Lots and lots of lubricating soap help but doen't fix that.
-- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
tirsdag den 20. oktober 2020 kl. 00.12.25 UTC+2 skrev Ricketty C:
rigid
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an cool looks. They make kayaks out of layered plastics with a weaker and lighter plastic as a core and a sturdier, but heavier plastic on the outsid e for strength. I thought that fiberglass over foam was a common technique for things like surf and body boards.
ey flex terribly. Giving them a core and stronger covering would certainly be stronger, but less flexible. When the limit is reached it would just f old. Look at the construction of a sumac tree. The core is all pith with the only real strength in the outer section.
int is for the outer layer to have compression strength and the inner layer provides spacing to provide gain, i.e. leverage.
rneath, on edge will provide lots of strength. Secure 1x4 to the edges as a frame and you've got a nice train board. My dad made something like that when we were kids.
ant to feel like a hacker a hollow core interior door
ll. They are usually truly hollow however and so have only the strength of the thin door material. Put anything remotely heavy on it and the surface will bow easily. It's also very easily dented. Ideal would be a foam cor e, thin laminate for looks and fiberglass surface for toughness.
llow core door. It was at the lake house so a girl friend could work from there instead of home. People like being right next to the water. I may u se it for a work space soon.
to-shelves/
nk it took two, one for the top and one for the four verticals. A few piec es of wood across the bottoms and some rails across the front, add some hom e made drawers and presto! A complete desk with drawers. It even had supp orts under the center drawer to store a drafting board (commonly used in th ose days). I've kept it all these years. The only issue was the drawers w ere made a bit too snug and as the wood swells from humidity they stick pre tty badly. Lots and lots of lubricating soap help but doen't fix that.
there's a reason why Ikea makes tables etc. like it, saves on materials and transport and is plenty strong for most things
tirsdag den 20. oktober 2020 kl. 00.50.21 UTC+2 skrev Lasse Langwadt Christ ensen:
of rigid
epoxy?
olystyrene
surfboards
h the grain
ger in that
OK if the
foam' aren't
the
something,
r table
equipment.
ything's
de
t would be
the custom
h prefer
ble than
than cool looks. They make kayaks out of layered plastics with a weaker an d lighter plastic as a core and a sturdier, but heavier plastic on the outs ide for strength. I thought that fiberglass over foam was a common techniq ue for things like surf and body boards.
They flex terribly. Giving them a core and stronger covering would certain ly be stronger, but less flexible. When the limit is reached it would just fold. Look at the construction of a sumac tree. The core is all pith wit h the only real strength in the outer section.
point is for the outer layer to have compression strength and the inner lay er provides spacing to provide gain, i.e. leverage.
derneath, on edge will provide lots of strength. Secure 1x4 to the edges a s a frame and you've got a nice train board. My dad made something like th at when we were kids.
want to feel like a hacker a hollow core interior door
well. They are usually truly hollow however and so have only the strength of the thin door material. Put anything remotely heavy on it and the surfa ce will bow easily. It's also very easily dented. Ideal would be a foam c ore, thin laminate for looks and fiberglass surface for toughness.
hollow core door. It was at the lake house so a girl friend could work fro m there instead of home. People like being right next to the water. I may use it for a work space soon.
into-shelves/
hink it took two, one for the top and one for the four verticals. A few pi eces of wood across the bottoms and some rails across the front, add some h ome made drawers and presto! A complete desk with drawers. It even had su pports under the center drawer to store a drafting board (commonly used in those days). I've kept it all these years. The only issue was the drawers were made a bit too snug and as the wood swells from humidity they stick p retty badly. Lots and lots of lubricating soap help but doen't fix that.
nd transport and is plenty strong for most things
a famous one is the LACK side table that cost about ~$10 and is a perfect f it for 19" gear
of rigid
epoxy?
olystyrene
surfboards
h the grain
ger in that
OK if the
foam' aren't
the
something,
r table
equipment.
ything's
de
t would be
the custom
h prefer
ble than
than cool looks. They make kayaks out of layered plastics with a weaker an d lighter plastic as a core and a sturdier, but heavier plastic on the outs ide for strength. I thought that fiberglass over foam was a common techniq ue for things like surf and body boards.
They flex terribly. Giving them a core and stronger covering would certain ly be stronger, but less flexible. When the limit is reached it would just fold. Look at the construction of a sumac tree. The core is all pith wit h the only real strength in the outer section.
point is for the outer layer to have compression strength and the inner lay er provides spacing to provide gain, i.e. leverage.
derneath, on edge will provide lots of strength. Secure 1x4 to the edges a s a frame and you've got a nice train board. My dad made something like th at when we were kids.
want to feel like a hacker a hollow core interior door
well. They are usually truly hollow however and so have only the strength of the thin door material. Put anything remotely heavy on it and the surfa ce will bow easily. It's also very easily dented. Ideal would be a foam c ore, thin laminate for looks and fiberglass surface for toughness.
hollow core door. It was at the lake house so a girl friend could work fro m there instead of home. People like being right next to the water. I may use it for a work space soon.
into-shelves/
hink it took two, one for the top and one for the four verticals. A few pi eces of wood across the bottoms and some rails across the front, add some h ome made drawers and presto! A complete desk with drawers. It even had su pports under the center drawer to store a drafting board (commonly used in those days). I've kept it all these years. The only issue was the drawers were made a bit too snug and as the wood swells from humidity they stick p retty badly. Lots and lots of lubricating soap help but doen't fix that.
nd transport and is plenty strong for most things
For certain values of "most things". Assume cows are spherical...
-- Rick C. -+ Get 1,000 miles of free Supercharging -+ Tesla referral code - https://ts.la/richard11209
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