X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao101.cox.net ([68.230.241.45] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2382649 for flyrotary@lancaironline.net; Fri, 12 Oct 2007 01:11:33 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.45; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao101.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20071012051051.POJU93.fed1rmmtao101.cox.net@fed1rmimpo03.cox.net> for ; Fri, 12 Oct 2007 01:10:51 -0400 Received: from BigAl ([72.192.143.193]) by fed1rmimpo03.cox.net with bizsmtp id zHAs1X0064AaN600000000; Fri, 12 Oct 2007 01:10:52 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Hose clamp myth busters Date: Thu, 11 Oct 2007 22:12:02 -0800 Message-ID: <000001c80c96$cec342f0$6401a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C80C53.C0A273F0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C80C53.C0A273F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Subject: [FlyRotary] Re: Hose clamp myth busters =20 Al, Can you tell me how to properly tighten or what the torque should be on = a good quality hose clamp or a constant torque clamp? This is a question I have never been able to find the answer. Thanks for your help. Robert =20 Rob; wasn=92t avoiding the question, just hadn=92t gotten to it. But = also don=92t have =93the=94 answer because it is too general =96 different clamps, = different sizes, different hose materials, different applications. Probably the = main difference in application is the pressure you expect it to hold. Rely on your good judgement. =20 I=92d say in general for cooling system applications, you tighten the = clamp about as tight as you can make it with a one hand on good size screw = driver (how=92s that for precise); squeeze the hose some, but not to damage it. = The torque will be in the range of maybe 10 to 30 inch-lbs. Then make sure = it doesn=92t leak under the pressure you want it to hold. =20 On my cooling system I have reinforced silicone compound hoses (blue = stuff from McMaster-Carr). My system is set up with dual caps in series with = the potential of 38 psi max pressure. I put the hoses on, tightened them to what seemed right, then pressurized to system to 38 psi. A couple of = the connections leaked, so I got my =BC=94 drive ratchet with the = appropriate socket, and tightened the clamp until the leak stopped. I=92m guessing = it was about 30 =96 35 inch lbs. I checked them a few weeks later and found I = could give most of them another partial turn to about the same torque level. Haven=92t touched them in the year of flying since, and there have been = no leaks, and the hoses still look as good as when they went on. I=92ll = probably replace most of them within the next year - just because. =20 Al ------=_NextPart_000_0001_01C80C53.C0A273F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Subject: [FlyRotary] Re: Hose clamp myth busters

 

Al,

Can you tell me how to = properly tighten or what the torque should be on a good quality hose clamp or a = constant torque clamp? This is a question I have never been able to find the = answer. Thanks for your help.

Robert

 

Rob; wasn’t avoiding the = question, just hadn’t gotten to it.=A0 But also don’t have = “the” answer because it is too general – different clamps, different = sizes, different hose materials, different applications. Probably the main difference in application is the pressure you expect it to hold. Rely on your good = judgement.

 

I’d say in general for = cooling system applications, you tighten the clamp about as tight as you can = make it with a one hand on good size screw driver (how’s that for = precise); squeeze the hose some, but not to damage it.=A0 The torque will be in = the range of maybe 10 to 30 inch-lbs. =A0Then make sure it doesn’t leak = under the pressure you want it to hold.

 

On my cooling system I have = reinforced silicone = compound hoses (blue stuff from McMaster-Carr).=A0 My system is set up with dual = caps in series with the potential of 38 psi max pressure. =A0I put the hoses on, = tightened them to what seemed right, then pressurized to system to 38 psi.=A0 A = couple of the connections leaked, so I got my =BC” drive ratchet with the = appropriate socket, and tightened the clamp until the leak stopped.=A0 I’m = guessing it was about 30 – 35 inch lbs.=A0 I checked them a few weeks later = and found I could give most of them another partial turn to about the = same torque = level.=A0 Haven’t touched them in the year of flying since, and there have been no leaks, = and the hoses still look as good as when they went on.=A0 I’ll probably = replace most of them within the next year - just because.

 

Al

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