<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>Re: CA hinges installation</TITLE>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2600.0" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial size=2>I have some questions regarding the foam friendly
CA. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Is it as thin and as strong as the regular stuff?
</FONT></DIV>
<DIV><FONT face=Arial size=2>If so why isn't all CA made to be foam friendly? It
would seem to me that if the chemistry of the CA is changed such that it didn't
damage foam then it is reasonable to assume that other properties may differ as
well. </FONT><FONT face=Arial size=2>In other words, what does one "give up" by
using the foam friendly stuff?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Without knowing this I'd be very concerned about
using it rather than the regular stuff. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Personally I'd think with just a few drops on the
hinge there wouldn't be enough foam damage to make a difference anyways. Think
about it, people honeycomb their wings. What's the big deal if a wee bit of foam
is eaten away? One argument may be that the trailing edge and control surfaces
aren't honeycombed and foam lost in these areas is more critical. Well I have a
hard time buying that. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>BTW, after writing the above paragraph I
experimented with this several times using a Radio City 1/4" scale hinge going
through 1/4" balsa into foam attached to the back side of the balsa. The
CA never did any damage to the foam and seemed to be absorbed completely by
the balsa. Of course, I didn't use the "Slot Machine" to make the slots, I used
a #11 blade. With wider slots the CA may make it's way to the foam more
easily. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>One thing I've noticed that all thin CA's are not
created equal. Therefore I would think the quality of the hinge may be effected
by type of CA one uses. For example, it's been my observation that the Bob Smith
Industries stuff (that every hobby shop puts their own name on) doesn't soak in
nearly as well as Zap CA. (If Bob Smith is on this forum my sincere apologies
for singling you out :-) ).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>And while I'm on a roll here. I've heard the crayon
idea many times before, and quite frankly it never made sense to me. My first
thought was that hinges are absorbent enough to wick the CA down into the hinge
slot, so why would crayon on the "outside" of the hinge prevent the CA from
wicking right through the middle of the hinge? Well, I did some tests with the
Radio City hinges and found that the hinge itself really isn't absorbent, not
without contacting balsa anyways. You can drip CA right on these hinges and it
will just puddle in droplets and not soak in. But touch a piece of balsa to it
and SLURP, the CA spreads through the wood and across the surface of the hinge
and bonds instantly. It appears that the balsa actually absorbs the CA and the
surface of the hinge provides a superb bonding surface. Probably due to its
texture (the chemist among us could probably explain, Gray, you
there?).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>So, in trying to prove that CA would soak under the
crayon I found that what really happens (on these hinges anyway) is that it
doesn't soak in at all, at least not deep into the hinge fabric. As to the
crayon I marked a hinge with a heavy crayon line on both sides and applied drops
of CA and as stated it pooled not only on the crayoned portion, but on the
non-crayoned portion. Therefore, my theory was incorrect, but I still am unsure
that the crayon would do any good. If you ended up with excess CA caked on the
hinge gap and you had a crayon line there then you'd just have CA caked over the
crayon line (I tested this and it does bond to the crayon line).
</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I'd be interested in hearing other's experiences
with different types of CA and opinions/suggestions about CA
hinges.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Keith Black</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=bcarpenter@greenvilleisp.net
href="mailto:bcarpenter@greenvilleisp.net">Bill Carpenter</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, February 10, 2003 11:13
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: CA hinges installation</DIV>
<DIV><BR></DIV>Another suggestion FWIW, if you have a foam wing core under the
balsa sheeting and glued to the trailing edge, use foam friendly CA. It
will not eat the foam if it gets in that deep. Also, some people either
drill a hole in the center of the slot to allow CA to go deeper into the slot
at the center, or some CA hinges come with a slot in the middle of them to
allow CA to go in the slot deeper. <BR><BR>Bill
3544<BR><BR>----------<BR>From: "Chris Larson"
<csmulti@volcano.net><BR>To: <discussion@nsrca.org><BR>Subject:
Re: CA hinges installation<BR>Date: Mon, Feb 10, 2003, 9:59 PM<BR><BR><BR>
<BLOCKQUOTE><FONT size=2><FONT face=Arial>Xavier-<BR>I have used a crayon
from my sons toy box, sharpened, and drawn along the hinge line. This
not only serves as an alignment point, but also as a release agent for the
glue. I guess I should also note I haven't used that method on most of
my planes ( just wicked in CA at the hinge line, let dry, and flex
vigorously back and forth ) with great results too. You shouldn't
worry too much about making the hinge stiff - just be sure you are using
THIN CA!! :-)<BR>Chris Larson<BR>NSRCA 3484<BR></FONT></FONT>
<BLOCKQUOTE>----- Original Message ----- <BR><B>From:</B> Anne &
Xavier <<FONT
color=#0000ff><U>mailto:xavier.mouraux@sympatico.ca</U></FONT>>
<BR><B>To:</B> <FONT
color=#0000ff><U>discussion@nsrca.org</U></FONT> <<FONT
color=#0000ff><U>mailto:discussion@nsrca.org</U></FONT>>
<BR><B>Sent:</B> Monday, February 10, 2003 7:56
PM<BR><B>Subject:</B> CA hinges installation<BR><BR><FONT size=2><FONT
face=Arial>Hi guys,<BR></FONT></FONT> <BR><FONT size=2><FONT
face=Arial>I am about to install the CA hinges (fiberglass) on two of my
winter projects and I would appreciate any recommandations on the proper
procedure to do it. I have the tight slots done. I am worrying about the
glue making the hinge stiff. How do I ensure the glue doesn't go in the
flexing area ?<BR></FONT></FONT> <BR><FONT size=2><FONT
face=Arial>Note that these are 2 sport planes that I am using to improve
my building skills before moving on to pattern plane building next year. I
have been flying second hand pattern
planes.<BR></FONT></FONT> <BR><FONT size=2><FONT
face=Arial>Thanks<BR></FONT></FONT> <BR><FONT size=2><FONT
face=Arial>Xavier<BR></FONT></FONT><BR></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>