On Sat, 21 Oct 1995, Matthew Williams wrote:
[some snipping]
> Incidentally, our inspector has advised us that we SHOULD peel ply the whole
> surface of layups, to further remove excess resin and to make a smoother
> surface (needing less filler to finish). He assured us that tales of
> structural weakening are rubbish, and sent us out to buy a roll of dacron
> (well, actually the stuff you line coats and jackets with). Is this just a
> contentious subject for speculation, or is there actually any hard evidence
> either way?
[more snip]
I am in the process of cutting a batch of 40% scale wing panels for
experimenting with different layup methods. THe different tests pannels
will be:
1. Standard Europa layup. Same number and type of piles with all
processes as close to the recommended methods as can be done. This will
be the referrenc test panel.
2. Standard Europw layup with full peelply, breather blanket, vacuum
bag. Vacuum drawn on panel until cured.
3. Glass layed up on a sheet of Mylar, Using a full width squeege to coat
the glass with consistent layer or resin much like is done in silk screen
printing. The Mylar/glass sheet to be rolled onto a prepared foam core.
The core will have been prepared with the micro slurry. After the glass
has been rolled onto the core a brether blanket and vacuum bag applied.
Vacuum drawn until cured.
4. Using one of the first test panels, probably the one from number 3
above, a female mold will be made up from epoxy/glass mat and will be
used as a female mold to lay up the glass skin. While the resin is still
wet the foam will be placed in the mold. Release film, breather blanket
and vacuum bag that seals to the mold flange. Vacuum drawn until cured.
The skin for the opposite side can be layed up while the panel is still
in the mold with or without the peelply followed by the breather blanket
and vacuum bag.
This should give the truest wing if the mold is carefully made and
reinforced so the vacuum forces will not twist it.
I would enjoy hearing from any of you that have other suggestions to
try. Since I will not be able to start my plane until sometime this
winter I am amusing myself with these tests. Hopefully I will come up
with a methos that will save finishing time, improve the accuracy of the
flying surfaces and hopefully result in stronger panels.
Steve
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