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titleMaterial strength of Acrylic (Plexiglas), PETG 3D printed plastics.

[1] Acrylic
Yield Strength: 64.8 - 83.4 MPa (Average value: 75.4 MPa)
Young’s Modulus: 2.76 - 3.30 GPa

Flexural Modulus: 2.96 - 3.30 GPa
Flexural Yield Strength: 98.0 - 125 MPa (Average value: 109 MPa)

[2] PETG
Yield Strength: 28.3 - 58.6 MPa
Young’s Modulus: 1.10 - 20.3 GPa (Average value of 2.65 GPa)

Flexural Modulus: 1.17 - 2.76 GPa
Flexural Yield Strength: 39.2 - 88.9 MPa (Average value of 69.5 MPa)

In short, Plexiglas is a strong enough viable alternative for the side walls of the cover.

Gel-coat
Protective finishing layer for composite surfaces.
Leaves a hard smooth surface good for sticking on adhesive.
Requires sanding and buffing for a smooth surface.
If painting the cover, apply gel-coat first then paint over it.

Source:
[1] http://www.matweb.com/search/datasheet.aspx?bassnum=O1303
[2] http://www.matweb.com/search/datasheet.aspx?matguid=4de1c85bb946406a86c52b688e3810d0

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Part Name

Mold and Manufacturing method

Notes

Top cover (Front)

  • No mold really required

  • Wet layup on a flat surface of glass

  • Creating a flat piece of the cover on glass provides a really smooth finish that does not need any additional sanding

  • Only one side needs to look nice

Top cover (Rear)

  • MDF mold

  • Infusion

  • Shape is pretty curved and arches backwards so MDF mold it is

Inner walls

  • Wet layup on a flat surface of glass

  • Not the main bearer of load

Front side walls

  • Wet layup on a flat surface of glass

  • Not sure if to do wet layup or infusion for the added strength because the side walls would need to support the panel on top resting on it

Rear side walls

  • MDF mold

  • Vacuum bagging infusion

  • CAD model for the wall seems too complicated to create a mold manually

Rubber seal

  • Hand cut with box cutter and a template for the exact shape

  • Laser cutting to shape

  • Send to 3rd party to manufacture

  • Few options available

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titleWaterproofing

Gasket for battery cover would be stamped out or cut out from a flat sheet of rubber to match the outline of where the cover would sit on the edges of the walls.
Neoprene is what is typically used for gaskets (synthetic rubber).


Gaskets could be manufactured by using die cutting, water-jet cutting, and laser-jet cutting.
Manufacturing could be potentially done in-house with a large enough laser cutter and a large sheet of rubber, or could potentially be made using a small blade slicing the rubber to the CADed shape.


For the seal to be effective, it should be one continuous piece that covers all openings and shall be compressed against the surface of the resting site and the cover so that small air gaps could be filled to prevent potential water from leaking.

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Assembly Detailing