Cheap/throwaway laminating table

Discussion in 'Fiberglass and Composite Boat Building' started by Scuff, Apr 11, 2022.

  1. Scuff
    Joined: Nov 2016
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    Scuff Senior Member

    I need a laminating table 7' x 19' for two bulkheads. Once they are done I won't need the table anymore. Cheap would be a bonus. Any thoughts or ideas much appreciated. Thanks
     
  2. fallguy
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    fallguy Senior Member

    odd size to only need 2

    can you break them in half and bond them with reinforcing tapes? That way, you would build a nice 4' wide table 24' long and then bond the seams to make 7' dimension

    my tables is/are made from 49"x96" 1" thick mdf
     
  3. Scuff
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    Scuff Senior Member

    I'm going to build them in one piece. How did you support/frame the mdf? I was thinking maybe torsion boxes using 1/2" mdf for the grid with plastic coated hard board for skins. I could reuse the hardboard for the deck mold.
     
  4. fallguy
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    fallguy Senior Member

    I bought i beams for floor joists and had them delivered. Mine were 36 footers. Room was 36' so had to cut some off to walk around one side. I used 4 under a 49" wide panel and ran four 8 footers and a piece. I made the table adjustable for level even. Way more elaborate than needed, but food for thought.

    iirc, we epoxy putty seamed, did two lifts of epoxy and polished to 400 grit

    for your oddball size; you might be working on the floor until the odd sizes are behind you..

    52990D63-374E-4C98-9005-60D5D6D7E70B.jpeg
     
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  5. fallguy
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    fallguy Senior Member

    The floor joists were nice because I was able to screw the top down from below without penetrating and the sides offered me places to hook vac lines to. And I got storage under the table and above the crossmembers the joists sat on..

    I actually made one or two of the gaps big enough for 4x8 panel stock and still have foam there now.

    Ended up cutting the table in half after the hulls were out of the building, so have 2 16' worktables now..
     
  6. Scuff
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    Scuff Senior Member

    I like the ibeam approach. I could make the beams and it sounds like less work than the torsion box. Thanks!
     
  7. ondarvr
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    ondarvr Senior Member

    Use the floor of the shop.
     
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  8. Scuff
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    Scuff Senior Member

    The floor isn't flat/consistent. It's got some pretty bad hollows in it. I regret the guys I used to do the floor but nothing to be done about that now.
     
  9. fallguy
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    fallguy Senior Member

    You can lay timbers one edge on the floor and build a flat large wide area woth 4x8 panels and good 2x6 timbers on edge (choose for straightness or buy timberstrand). Shim and hotglue the thing down to make it flat. Use strings to verify flatness. Like a mason's line...

    If you need to use vac; you bond mdf on all the seams and then cut them out after the big panels are done.

    No vac, just push them together and hole them at 8' edges and screw top down. After the big panels are done, take it all apart and build regular 49" wide tables...repair the holes with epoxy

    You can hand laminate on 6mil plastic for the big panels.
     
  10. hoytedow
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    hoytedow Carbon Based Life Form

    You can use wedges under the legs to compensate for the uneven floor.
     
  11. redreuben
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    redreuben redreuben

    Glossy melamine sheet on mdf or chipboard gives the best finish and release.
     
  12. Scuff
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    Scuff Senior Member

    Update. I'm using the torsion box approach. The total cost is under $300 us. 1/2" mdf for the guts and 1/4" hardboard for skins. I could not find hardboard with a melamine coating .. it's all coated with acrylic paint. The hardboard readily accepts mold release wax and my test had a clean release with two coats. I'll tape the screw holes and then wax between. I'm guessing the weight is around 120lbs for 4x8 panel. PXL_20230108_192320518.jpg PXL_20230108_191835208.jpg
     
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  13. fallguy
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    fallguy Senior Member

    mdf without sealing may leak thru acrylic paint, but may not matter
     
  14. redreuben
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    redreuben redreuben

    Give it a couple of coats of waxed poly resin if you have any.
    Apply 2nd coat when 1st has gelled off a bit.

    If you want to go to the trouble waxed poly resin or gelcoat can be wet sanded and buffed to a very high gloss.
     
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  15. wet feet
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    wet feet Senior Member

    Shellac works well as a sealer,the first coat will be quite fuzzy and use a lot and after de-nibbing you will use a lot less for a second coat.You can flat it with 320 paper to achieve a good satin finish.three coats of wax normally works but an extra coat takes very little time.I'd be a bit anxious about the hardboard staying flat over that frame.
     
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