Polystyrene packaging

[Daren Cogdon]

I have a few sheets of polystyrene - the kind of thing that's used for packaging in things like fridges, for example (in fact, I think this was from a fridge!)

 

It's pretty flimsy, but could it be used as a construction material?  I would say it's about 10mm thick, at most. 

 

If suitably reinforced with, say, PVA and brown paper?

[Nigel R]

White bead foam has been used for ages as a core material for wings and things. Packaging for white goods will probably be quite "heavy" foam though.

[Martin Gay]

This own design A320 was built with the foam packaging from a shower screen!

 

[Daren Cogdon]

12 minutes ago, Martin Gay said:

This own design A320 was built with the foam packaging from a shower screen!

 

 

That's pretty awesome!

[Daren Cogdon]

22 minutes ago, Nigel R said:

White bead foam has been used for ages as a core material for wings and things. Packaging for white goods will probably be quite "heavy" foam though.

Nah, this is pretty light.  I have five sheets of it - three at 10mm and two about 12mm, and each sheet probably weighs about as much as the A3-sized foam-board sheets that I have lying around.

[Graham Davies 3]

Everything is possible. I have some 25mm sheets that protected my fridge when it was delivered. I laminated a few thicknesses and made cowls for several models from it!

[SIMON CRAGG]

Yes is the answer!.

 

We are modeller.......so anything is possible.

 

I have done some experiments in the past, and it can make a good core, covered in brown paper and strengthened with a carbon rod.

 

I would cut up a few small pieces and try out some different techniques.

 

Worth a try at least!.

[Daren Cogdon]

I never thought about the carbon rod - definitely need to try that, too.  

[Ace]

A 1" wide strip of grass reinforced packing tape wrapped tip to tip top and bottom works very well in tension, light and easy to add. 

[kc]

What sort of "grass reinforced tape"?    ordinary lawn grass?

 

Anyway being serious - the foam used in foam wings was 1 pound per cubic foot stuff, so anything like that should be OK.   Measure in inches - 1728 cu inches per cu foot of course.

[Phil Curtis 1]

Hornet photo below, made from B&Q insulation foam, strengthened leading edge with balsa and carbon spar in wing, flys superb. Plans from outer zone.

[Ace]

17 hours ago, kc said:

grass reinforced tape

Dam auto complete and not checking 🥵

Edited November 25, 2023 by Ace

[Simon Chaddock]

Daren

As you can see from the replies polystyrene 'packing' foam has very little "structural" strength so it use is all about how it is reinforced.

Obviously adding reinforcing to the surface of the foam is gives the best stiffness to weight ratio but it needs experience to use the right material(s) in the right way.

Adding a high strength material like a carbon tube is relatively simple to do but provides no protection to the foam's soft outer surface.

A combination of both of these techniques may provide the best solution.

 

Using soft foam to build a plane, although it may be plentiful and free,  is not quite as simple as it might appear.