X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.8) with ESMTP id 4397680 for flyrotary@lancaironline.net; Sun, 18 Jul 2010 19:46:14 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id E0B7E17359C for ; Mon, 19 Jul 2010 07:45:36 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 6724FBEC016 for ; Mon, 19 Jul 2010 07:45:32 +0800 (WST) Message-ID: <3B411005A79441A4A28D908A17C513AC@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Tie Down Hardpoints Date: Mon, 19 Jul 2010 09:45:38 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0007_01CB2727.24A286B0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5931 X-Antivirus: avast! (VPS 100718-0, 07/18/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0007_01CB2727.24A286B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thomas, That is very interesting and informative and I appreciate you quoting = it; but nowhere do I see it say that stainless will deteriorate in a non = oxygen environment once it has become passivated.=20 Still it's information I never had before and I appreciate that. I must = admit however that have I seen evidence of stainless steel deterioration = ( oxidation or rusting) in other than carbon stainless, or pitting in = stainless in extreme environments. The only thing I've seen it do is go = dull over a number of years, perhaps that's the oxidation process they = refer to. If that is the case I don't see a major problem there. George ( down under) Yeah ... I just know what I read. Here is the explanation I read: "The basic resistance of stainless steel occurs because of its ability = to form a protective coating on the metal surface. This coating is a = "passive" film which resists further "oxidation" or rusting. The = formation of this film is instantaneous in an oxidizing atmosphere such = as air, water, or other fluids that contain oxygen. Once the layer has = formed, we say that the metal has become "passivated" and the oxidation = or "rusting" rate will slow down to less than 0.002" per year (0,05 mm. = per year). Unlike aluminum or silver this passive film is invisible in stainless = steel. It's created when oxygen combines with the chrome in the = stainless to form chrome oxide which is more commonly called "ceramic". = This protective oxide or ceramic coating is common to most corrosion = resistant materials." -------------------------------------------------------------------------= ----- From: "George Lendich" Sent: Sunday, July 18, 2010 5:17 PM To: "Rotary motors in aircraft" Subject: [FlyRotary] Re: Tie Down Hardpoints Thomas, Well that's a new one on me. Sound to me you might be getting = confused with Anodized Aluminium. I know lower grade stainless can pit = because of electrolysis in extreme environments and because of that they = use 316 ( marine) grade. I know carbon grade stainless can rust However if anyone can confirm this I would appreciate hearing further = about it. George ( down under) I think I want to stay away from the stainless because it will be = completely enclosed in fiberglas. Stainless needs to be exposed to an oxygen environment in order to = for that protective layer (chrome oxide) that prevents further = oxidation. At least that's what I've been told/read. -------------------------------------------------------------------------= --- Thomas, I agree with Tony, use something that won't rust, nothing looks = worse on the exterior of a plane. Maybe consider stainless steel, I use = it on everything. George (down under) Hey Tony. Now I'm looking for the tie down hardpoints (either parts or = specs) referenced on page 25 of the 'A' kit manual. I have not found them in the drawings either. They say thay are Cad plated steel. I can have them made but I = would be guessing.=20 Maybe .125 3" x 3.5" plate would suffice with a threaded steel = bushing welded to it and then plated. I figure the bushing threaded/tapped 1/4" x 28 could be 5/8" = material ... maybe. ... or 3/4". Any Ideas? Thanks. T Mann=20 ------=_NextPart_000_0007_01CB2727.24A286B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 Thomas,
That is very interesting and = informative and I=20 appreciate  you quoting it; but nowhere do I see it say that = stainless=20 will deteriorate in a non oxygen environment once it has become = passivated.=20
 
Still it's information I never had = before and I=20 appreciate that. I must admit however that have I seen evidence of=20 stainless steel deterioration ( oxidation or rusting) in other than = carbon=20 stainless, or pitting in stainless in extreme environments. The = only thing=20 I've seen it do is go dull over a number of years, perhaps that's=20 the oxidation process they refer to. If that is the case I don't = see a=20 major problem there.
George ( down under)
Yeah=20 ... I just know what I read.

Here is the explanation I=20 read:

"The basic resistance of stainless steel occurs because = of its=20 ability to form a protective coating on the metal surface. This = coating is a=20 "passive" film which resists further "oxidation" or rusting. The = formation of=20 this film is instantaneous in an oxidizing atmosphere such as air, = water, or=20 other fluids that contain oxygen. Once the layer has formed, we say = that the=20 metal has become "passivated" and the oxidation or "rusting" rate will = slow=20 down to less than 0.002" per year (0,05 mm. per year).

Unlike = aluminum=20 or silver this passive film is invisible in stainless steel. It's = created when=20 oxygen combines with the chrome in the stainless to form chrome oxide = which is=20 more commonly called "ceramic". This protective oxide or ceramic = coating is=20 common to most corrosion resistant materials."

From: "George Lendich" = <lendich@aanet.com.au>
Sent:=20 Sunday, July 18, 2010 5:17 PM
To: "Rotary motors in = aircraft"=20 <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: = Tie=20 Down Hardpoints

 Thomas,
Well that's a new one on me.  = Sound to me=20 you might be getting confused with Anodized Aluminium. I know lower=20 grade stainless can pit because of electrolysis in extreme = environments=20 and because of that they use 316 ( marine) grade. I know carbon grade=20 stainless can rust
However if anyone can confirm this I=20 would appreciate hearing further about it.
George ( down under)
I=20 think I want to stay away from the stainless because it will be = completely=20 enclosed in fiberglas.
Stainless needs to be exposed to an oxygen = environment in order to for that protective layer (chrome oxide) = that=20 prevents further oxidation.

At least that's what I've been=20 told/read.


 Thomas,
I agree with Tony, use something = that won't=20 rust, nothing looks worse on the exterior of a plane. Maybe consider = stainless steel, I use it on everything.
George (down under)
Hey=20 Tony.
Now I'm looking for the tie down hardpoints (either parts = or=20 specs) referenced on page 25 of the 'A' kit manual.

I have = not=20 found them in the drawings either.

They say thay are Cad = plated=20 steel. I can have them made but I would be guessing.
Maybe = .125 =20 3" x 3.5" plate would suffice with a threaded steel bushing welded = to it=20 and then plated.
I figure the bushing threaded/tapped 1/4" x 28 = could=20 be 5/8" material ... maybe. ... or 3/4".

Any=20 Ideas?

Thanks.

T Mann=20

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