X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 1 [X] Return-Path: Sender: To: lml Date: Sat, 13 Jan 2007 22:43:49 -0500 Message-ID: X-Original-Return-Path: Received: from relay3.av-mx.com ([137.118.16.123] verified) by logan.com (CommuniGate Pro SMTP 5.1.4) with ESMTP id 1757309 for lml@lancaironline.net; Sat, 13 Jan 2007 21:17:42 -0500 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.123; envelope-from=pinetownd@volcano.net X-Virus-Scan-Time: 0 Received: from [137.118.16.62] (HELO mx1.av-mx.com) by relay3.av-mx.com (CommuniGate Pro SMTP 4.2.10) with SMTP id 567992060 for lml@lancaironline.net; Sat, 13 Jan 2007 21:16:53 -0500 Received: (qmail 2351 invoked from network); 14 Jan 2007 02:16:53 -0000 Received: from 65-166-101-112.du.volcano.net (HELO DennisDell) (pinetownd@volcano.net@65.166.101.112) by 0 with SMTP; 14 Jan 2007 02:16:53 -0000 X-CLIENT-IP: 65.166.101.112 X-CLIENT-HOST: 65-166-101-112.du.volcano.net X-Original-Message-ID: <003a01c73782$0e8f3190$6501a8c0@DennisDell> From: "Dennis Johnson" X-Original-To: "Lancair Mailing List" Subject: Solder, Crimps, and Physics X-Original-Date: Sat, 13 Jan 2007 18:16:52 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0037_01C7373E.FFAAEB80" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 This is a multi-part message in MIME format. ------=_NextPart_000_0037_01C7373E.FFAAEB80 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Greetings, Regarding the recent discussion of solder connections vs. crimped = connectors, we ought to look at the physics. The claim is often heard = that a soldered joint is rigid and that vibration flexes the wire back = and forth and work hardens the copper at the point where it becomes = rigid, which will then make the wire break at that point. =20 But think about a crimped connector. Where the wires enter the metal = barrel, the individual strands are squished into basically a single = piece of copper, as rigidly as if they were soldered. (A crimped = connector has to squeeze the strands so tight that it makes the joint = air tight.) The AMP PIDG connectors add a second barrel to crimp the = insulation to reduce this risk, but it seems to me that there is still a = transition point where the flexible, stranded, wires become essentially = a single, solid wire. So both soldered joints and crimped ones have exactly the same physics: = in both cases, flexible multi-strand wires are turned into a single, = rigid piece of copper. As someone has already said here, the key is to = support the wire near the connector to minimize vibration-induced = flexing. Good advice. I believe soldered connections aren't used in factories any more because = soldering requires more skill than crimping. An aircraft factory uses = calibrated crimpers that are relatively insensitive to operator = variability. I use both soldered connections and crimped ones, = depending on whichever seems more convenient for that particular = connection. For crimped connections, I use low cost ratchet crimpers = and high quality AMP PIDG connectors. Harbor Freight sells a crimper = that works great; B&C and SteinAir also sell great ones at affordable = prices. For soldered connections, I use a fancy soldering iron I bought = on EBay, but just about any soldering iron will work if you spend the = time to learn how to use it.=20 Dennis Johnson Legacy #257, connecting millions of tiny instrument panel wires to = millions of tiny airframe wires; hoping for first flight in February. ------=_NextPart_000_0037_01C7373E.FFAAEB80 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable

Greetings,

Regarding the recent discussion of solder connections vs. crimped=20 connectors, we ought to look at the physics. The claim is often = heard that=20 a soldered joint is rigid and that vibration flexes the wire back and = forth and=20 work hardens the copper at the point where it becomes rigid, which will = then=20 make the wire break at that point.

But think about a crimped connector. Where the wires enter = the metal=20 barrel, the individual strands are squished into basically a single = piece=20 of copper, as rigidly as if they were soldered. (A crimped = connector has=20 to squeeze the strands so tight that it makes the joint air = tight.) The=20 AMP PIDG connectors add a second barrel to crimp the insulation to = reduce this=20 risk, but it seems to me that there is still a transition point where = the=20 flexible, stranded, wires become essentially a single, solid wire.

So both soldered joints and crimped ones have exactly the same=20 physics: in both cases, flexible multi-strand wires are turned = into a=20 single, rigid piece of copper. As someone has already said here, = the key=20 is to support the wire near the connector to minimize vibration-induced=20 flexing. Good advice.

I believe soldered connections aren't used in factories any more = because=20 soldering requires more skill than crimping. An aircraft factory = uses=20 calibrated crimpers that are relatively insensitive to operator=20 variability. I use both soldered connections and crimped ones, = depending=20 on whichever seems more convenient for that particular connection. = For=20 crimped connections, I use low cost ratchet crimpers and high quality = AMP PIDG=20 connectors. Harbor Freight sells a crimper that works = great;=20 B&C and SteinAir also sell great ones at affordable prices. = For=20 soldered connections, I use a fancy soldering iron I bought = on EBay, but=20 just about any soldering iron will work if you spend the time to learn = how to=20 use it.

Dennis Johnson

Legacy #257, connecting millions of tiny instrument panel wires to = millions=20 of tiny airframe wires; hoping for first flight in February.

------=_NextPart_000_0037_01C7373E.FFAAEB80--