The Big Reveal

Today I pulled the shell out of the mould. Everything went OK, could have been better and could have been a lot worse. So there was no gaps in-between any plys which is a good thing. There has been a few issues with the plys moving after the pressure has been applied, I think this is to do with the PVA glue. And the only other issue is the seams, I Need to get the each leaf of veneer measured exact; the seams looked perfect in the mould, but moved out about 2-3mm.

Some things that I have learnt from this shell:

  • PVA glue takes WAY too long to cure – 24hr isn’t enough. The time is too long, so I will switch back to Titebond III.
  • PVA glue is more prone to rippling – this could also be an issue with clamp time, not sure.
  • The shell will stick to the mould – this is pretty common sense, if the shell has glue being squeezed out at the sides, it is going to glue itself to the mould. I think this can be overcome by either coating the shell in a few coats of tung oil or similar (because that stops glue from sticking so well or using wax paper in between the shell and the veneer.
  • I need a new mould – This mould has broken, glue has become unstuck and I don’t think it’s strong enough.

Any suggestions? Feel free to contact me/leave a comment.

  1. Hey Andy,
    Great work on this blog. The tests for this ply shell process was been very interesting to follow. I love to use mdf for jigs because it’s cheep and very flat. However, the mdf might have something to do with the strength of your mold. When I first tried to make a ply hoop I made the mold out of mdf and it snapped in half the second time I used it. You may want to try using 3/4″ plywood the next time around. Since it uses actual layers of wood instead of compressed sawdust the plywood is much more ridged.

    • andyvanzant
    • July 27th, 2009

    Hey, thanks for the tip. I will check out plywood, im going to be making a new mould in the next day or two, changng design a bit. I plan on using thicker, 12mm mdf, with either a 12 or 24mm gap inbetween.

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