Sandwich panel is a “filler material” (like plywood or foam) sandwiched between a fabric (we use fiberglass or carbon fiber). We use sandwich panel for the fins and the bulkheads


  1. Clear off a flat surface for the sandwich panel

  2. Cut two layers of vacuum bag to be 2-4” larger than the desired sandwich panel size 

  3. Cut breather (white fluffy material), and peel ply (special plastic bag with small holes) to be about 1” larger than the desired sandwich panel size 

  4. Cut the filler material and fabric to the correct size; cut a piece of fabric for each ply and each side 

  5. On top of the steel table, place one layer of vacuum bag and breather; set aside 

  6. Place one layer of mylar down on your work surface to keep the surface and the sandwich panel clean 

  7. Mix some epoxy in the correct ratio. Mix with a popsicle stick - avoid touching epoxy with bare skin - until the epoxy is a uniform color. 

  8. Over the mylar, pour a layer of epoxy on the filler material tools – just enough to make the material sticky - and spread with rubber spreader 

  9. Carefully place the fabric on top of the filler material, making sure not to pull the fibers at an angle or allow any air bubbles. Use gloved hands to work the material straight and work out any air bubbles. 

  10. Pour more epoxy on top of the fabric, and carefully spread. To avoid pulling the fabric, only spread in the direction of the fibers. You only need enough epoxy to make sure the entire fabric is wet. 

  11. Replace steps 9 and 10 for every ply of fabric 

  12. Gently place peel ply on the finished side; smooth out any bubbles and make sure the fabric  does not appear to be pulled out of shape

  13. Flip filler material over and lay carefully on top of the mylar, being careful not to disturb the fibers. 

  14. Repeat steps 8-12 on the other side 

  15. Carefully place on the breather on the steel table 

  16. Place the other breather layer and vacuum bag on the sandwich panel 

  17. Cut a small hole in the top vacuum bag to insert the vacuum hose 

  18. Insert the vacuum hose, place the flat metal piece on the hose once it is on the inside of the bag, and twist on Use vacuum tape (yellow, foamy clay-like substance stored in rolls of tape) to seal either side of the vacuum bag 

  19. Turn on the vacuum pump 

  20. Listen for leaks – fill these in with more vacuum tape 

  21. The vacuum should pull 0.7 bar

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