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<TITLE>Re: Stongest Plastic Glue (thanks)</TITLE>
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<P><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: ||| Philip Pilgrim ||| [<A HREF="mailto:thelab@sprint.ca">mailto:thelab@sprint.ca</A>]</FONT>
<BR><FONT SIZE=2>> Sent: 26 January 2000 12:56</FONT>
<BR><FONT SIZE=2>> To: synth-diy@mailhost.bpa.nl</FONT>
<BR><FONT SIZE=2>> Subject: Re: Stongest Plastic Glue (thanks)</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Thanks for all of the glue help. I eneded up using a pvc specific glue that seemed > to bond well. I then encapsulated the whole joint with 24hr epoxy. It seems very </FONT></P>
<P><FONT SIZE=2>> strong. Here are some things I learned from all of the emails and talking to </FONT>
<BR><FONT SIZE=2>> people:</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> 1. The longer epoxy's rated cure time, the stronger the joint (ie: 24hr Epoxy is </FONT>
<BR><FONT SIZE=2>> stronger than 15min Epoxy is stronger than 5minEpoxy)</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> 2. When working with moulded plastics, it is better to use glues that "weld" the </FONT>
<BR><FONT SIZE=2>> plastic (they eat it into a gelly then harden thus fuseing the two pieces) Most </FONT>
<BR><FONT SIZE=2>> adhesives are just surface bonders.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> 3. The mixing of fibreglass strands in the epoxy is quite clever. I only received </FONT>
<BR><FONT SIZE=2>> this email 30mins after I epoxied the plastic bits :(</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> 4. Italian designed synths are frail</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Thanks all</FONT>
<BR><FONT SIZE=2>> Philip</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Philip Pilgrim The Lab</FONT>
<BR><FONT SIZE=2>> 5 Evan's Drive Synth Mods/Repair</FONT>
<BR><FONT SIZE=2>> Hammond's Plains Software </FONT>
<BR><FONT SIZE=2>> N.S. Canada <A HREF="http://www.robotnik.com/the_lab" TARGET="_blank">http://www.robotnik.com/the_lab</A></FONT>
<BR><FONT SIZE=2>> B4B 1M8</FONT>
<BR><FONT SIZE=2>> </FONT>
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<BR>
<P><FONT SIZE=2>I would also add my experiences after using epoxy for more than twenty years (I even built a boat with the stuff, and used to buy resin + hardener by the gallon...)</FONT></P>
<P><FONT SIZE=2>5. Heat speeds up the curing process, but doesn't improve strength.</FONT>
</P>
<P><FONT SIZE=2>6. Roughening the surfaces to be mated improves the bonding strength</FONT>
</P>
<P><FONT SIZE=2>7. Some plastics have a waxy feel (like nylon); Epoxy doesn't bond well with these.</FONT>
</P>
<P><FONT SIZE=2>8. Normal 50/50 epoxy sets hard and rigid. If the thing being fixed is designed to flex, then a more durable bond will result from a 40/60 (resin/hardener) mix.</FONT></P>
<P><FONT SIZE=2>9. If you want to create a thick non-flowing mixture (like a filler), there is a silicon 'fluff' that can be added.</FONT>
</P>
<P><FONT SIZE=2>10. If it gets too cold, both the resin and hardener can go 'off' (crystals form, and remain even after warming-up). </FONT>
</P>
<P><FONT SIZE=2>11. The curing is a chemical reaction, and produces heat. If it's a warm day, and the mixture exceeds a certain critical mass (half a pint or so), you can get a sort of thermal runaway, where the mixture heats up beyond boiling point and turns into a solid brick in seconds. Fires have been caused!</FONT></P>
<P><FONT SIZE=2>Rod</FONT>
</P>
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