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<DIV><FONT face=Arial color=#000000 size=2>Are you hungry too? How about a
filet?.......</FONT></DIV>
<DIV> </DIV>
<DIV>Amir Neshati - REALTOR<BR>Prudential Americana Group<BR>The Wesley &
Tracy Drown Team<BR>871 Coronado Center Drive, Suite 100<BR>Henderson, Nevada
89052<BR>(702) 505-3085<BR><A
href="http://www.wesleydrown.com">www.wesleydrown.com</A><BR><A
href="http://www.lvvertical.com">www.lvvertical.com</A></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=brianyemail-nsrca@yahoo.com
href="mailto:brianyemail-nsrca@yahoo.com">brianyemail-nsrca@yahoo.com</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, January 17, 2005 10:02
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: epoxy joint</DIV>
<DIV><BR></DIV>
<DIV>All this talk of Joints has me
Buzzing......... <IMG
src="http://us.i1.yimg.com/us.yimg.com/i/mesg/tsmileys2/14.gif"></DIV>
<DIV> </DIV>
<DIV>......</DIV>
<DIV> </DIV>
<DIV>Brian</DIV>
<DIV><BR><BR><B><I>John Crozier <<A
href="mailto:sjcrozier@comcast.net">sjcrozier@comcast.net</A>></I></B>
wrote:</DIV>
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<DIV><FONT face=Arial size=2>Gray,</FONT></DIV>
<DIV><FONT face=Arial size=2>My next project will use composite horns
inserted into precision, re-enforced slots in the balsa
elevator/aileron.</FONT></DIV>
<DIV><FONT face=Arial size=2>Instructions say "Might want to add some milled
fiberglass to the epoxy".</FONT></DIV>
<DIV><FONT face=Arial size=2>Your response confirms my notion not to do
that.</FONT></DIV>
<DIV><FONT face=Arial size=2>Thanx..croz (chose your
"joints" wisely, even on the mainland))</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=gfowler@raytheon.com href="mailto:gfowler@raytheon.com">Gray E
Fowler</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, January 17, 2005 9:57
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: epoxy joint</DIV>
<DIV><BR></DIV><BR><FONT face=sans-serif size=2>John,</FONT> <BR><BR><FONT
face=sans-serif size=2>I do not understand what you mean composite
horns/balsa.....but I do know a thing about joints ( I once lived in
Hawaii hanging out with the locals).</FONT> <BR><FONT face=sans-serif
size=2>Epoxy is the "toughest" unfilled. By this I means in a seam joint
the primary stress will be flexing, and an unfilled epoxy can handle this
the best.</FONT> <BR><FONT face=sans-serif size=2>Milled fibers are about
1/64" long. In a composite the fibers are far stronger than the resin. The
job of the resin is to flex a <B>little</B> to enable stress to be
transferred from one fiber to another. The problem with milled fibers is
that as the transfer stress it is only for that 1/64 of a inch and then it
terminates creating a stress riser. The epoxy then fractures at the end of
that fiber at a stress level much lower than if the fiber was not there at
all. These type of fibers work great on thermoplastics which are much
softer and flexable, but not so great on thermosets. Milled fibers in an
epoxy will<B> reduce</B> elongation, <B>reduce</B> tensile strength,
<B>increase</B> the heat distortion temperature, <B>increase</B> hardness
and <B>increase</B> compression strength.</FONT> <BR><BR><FONT
face=sans-serif size=2>Microballoons are not structural, they are used to
reduce density. The volume is huge and the balloons are weak therefore the
mixture is weaker in every aspect. The reality is though that a
microballoon epoxy is still usually strong enough for our applications.
Add this to the fact that we are always striving for weight reduction and
you can determine the proper application. </FONT><BR><BR><FONT
face=sans-serif size=2>Filets in general are useless other than for
cosmetic reasons. On a properly assembled bond joint the filet will never
see stress until the load capacity of the joint itself is exceed. At that
point the joint breaks and considering that the joint itself is orders of
magnitude stronger than the filet, the filet breaks instantly. Filets are
dead weight, and usually more dead weight than you think it is-but man
they sure look GOOD when someone inspects the inside of your plane-which
in this hobby is second only to winning the NATs (sorry-cannot always stop
the sarcasm). <BR><BR><BR><BR>Gray Fowler<BR>Principal Chemical
Engineer<BR>Composites Engineering</FONT> <BR><BR><BR>
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<TD><FONT face=sans-serif size=1><B>"John Crozier"
<sjcrozier@comcast.net></B></FONT> <BR><FONT face=sans-serif
size=1>Sent by: discussion-request@nsrca.org</FONT>
<P><FONT face=sans-serif size=1>01/15/2005 09:35 AM</FONT> <BR><FONT
face=sans-serif size=1>Please respond to discussion</FONT> <BR></P>
<TD><FONT face=Arial size=1>
</FONT><BR><FONT face=sans-serif size=1>
To: "discussion nsrca"
<discussion@nsrca.org></FONT> <BR><FONT face=sans-serif
size=1> cc:
</FONT> <BR><FONT face=sans-serif size=1>
Subject: epoxy
joint</FONT></TD></TR></TBODY></TABLE><BR><BR><BR><FONT face=Arial
size=2>Sometime in my crafting life, I have acquired the notion that
adding milled glass, micro-balloons, etc., to epoxy when making a
good fitting joint, only weakens the joint. (diminishes, or dilutes the
bonding strength of the epoxy).</FONT> <BR><FONT face=Arial size=2>In this
case it would be composite horns to balsa. No fillet is
needed.</FONT> <BR><FONT face=Arial size=2>Anybody wanna jump in?</FONT>
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