Gidday,
I want to sand the underside of a glass flange that was not protected with
peel ply on one of my ailerons. I protected one side of the closeout foam
core extension for one skin but not the other. After removing the closeout
foam the area not peel plied was abraded but how much is the question? On
initial abrasion I was able to remove all the blue residual styrofoam. A
trouble light was excellent at highlighting the areas that needed more
work. If you look very closely at the exposed flange it has a white residue
all over it, except that it has a patchwork effect all through it which I
can only presume is the top of the bubbles of foam, or put it another way,
the "crater rims".
The dilemna is that when you sand the white residue which must be my
miroslurry, you get a white dust residue. When you sand glass skin you get
the same residue! Should I sand the flange until no more whitish
microslurry remains, but thats all, or should I remove all the blue
styrofoam, apply acetone to thoroughly remove foam remnants and abrade the
top of the white residue for closeout bonding? In other words should I
leave it there or take it away.
A further anxiety exists in that the 1st ply of cloth of the applicable
skin is completely translucent and I can't make out a fibre orientation.
The top ply's fibres however are clearly discernable when looking through
the flange from below. You could easily be tricked into thinking it isn't
there, but I know it is! If I could see a fibre orientation of the 1st
underside ply I would be confident in sanding down to the top of the
fibres. Last thing I want to do is be a bit overexuberant and have my
closeout displace the aileron as it should, but load only 1 skin, not2.
Hypothetically you could get a failure of the intersection of skin and
closeout and I don't want that. Better I ask these questions and be sure
than not ask and doubt my project, I reckon. One thing I do know now is I
will use peel ply ontop of any foam that is to be removed later. I now have
some peel ply that is very thin in comparison to the Europa type.
Any help would be appreciated.
Reg
Tony Renshaw
Reg
Tony Renshaw
Builder No.236
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