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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I’m not an engineer by any stretch,
but it seems there are two issues here – bond strength and fillets. </span></font></p>
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10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Bond strength – I think a sounds
epoxy joint will be stronger than the materials bonded in just about any case –
the joint seldom fails usually it’s the material pas the joint. (ergo
slow setting epoxy, poly-u or whatever to penetrate the material and spread the
stress on the joint?) A well known pilot uses Elmers or similar to set wood
spars in foam wings – the joint’s stronger than the surrounding
foam so no prob. </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Fillets – I think the purpose of a
fillet is to spread the load across a larger area than just the mating
surfaces, and thus dissipate stress risers or focused points of stress? They’re
often an easy/ cheap/ light way of getting more durable joints. </span></font></p>
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10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Can’t wait to hear someone w/ more
than seat of the pants experience on this – </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>-Rick </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>-----Original Message-----<br>
<b><span style='font-weight:bold'>From:</span></b> discussion-request@nsrca.org
[mailto:discussion-request@nsrca.org] <b><span style='font-weight:bold'>On
Behalf Of </span></b>John Crozier<br>
<b><span style='font-weight:bold'>Sent:</span></b> </span></font><font size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>Saturday,
January 15, 2005</span></font><font size=2 face=Tahoma><span style='font-size:
10.0pt;font-family:Tahoma'> </span></font><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>10:35 AM</span></font><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'><br>
<b><span style='font-weight:bold'>To:</span></b> discussion nsrca<br>
<b><span style='font-weight:bold'>Subject:</span></b> epoxy joint</span></font></p>
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style='font-size:12.0pt'> </span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>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).</span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>In this case it would be composite
horns to balsa. No fillet is needed.</span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Anybody wanna jump in?</span></font></p>
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