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<DIV><FONT face=Arial size=2>I've just rejoined the discussion list and noticed
a great discussion on vacuum bagging. I also have the low cost ACP vacuum
bagging system and I love it. I've done wings for a couple of sport models
and a few EDF kits and am very happy with the results.</FONT></DIV>
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<DIV><FONT face=Arial size=2>Someone posted that the ACP system draws a 3 psi
vacuum. That seems about right. If you do the math for a 200 sq in
wing panel, that's equal to stacking 600 lbs on top of your wings! And,
the pressure is perfectly distributed, ensuring a solid bond between the skin
and the core.</FONT></DIV>
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<DIV><FONT face=Arial size=2>One trick I started doing a few years ago is using
polyurethane glue (Gorilla or Elmers Pro Bond) instead of epoxy. My
technique is to edge sand the skin sheets and then tape then together on the
outside of the skin. I then apply the glue to the inside of the skin and
take an old credit card to squegee off the excess. I leave just enough
glue to make the skin appear damp. I then place the skins on the core,
wrap with breather cloth and insert into the bag. I then place the
assembly back into the cradles and add some weight (2 large books are enough) to
stabilize the assembly. Once I'm happy with the alignment of the cradles,
skins, and cores, I start the pump and let it run 18 to 24 hours. The next
evening I have a very light, perfectly skinned wing. The bond is extremely
strong because during the curing process, the glue soaks into the skins and it
foams and works its way down into the core. The glue also seeps into
the butt joints of the skins and bonds them with virtually no ridges on the
outsides of the skins.</FONT></DIV>
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<DIV><FONT face=Arial size=2>I've become a firm believer in vacuum
bagging.</FONT></DIV>
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<DIV><FONT face=Arial size=2>Rob</FONT></DIV></BODY></HTML>