Return-Path: <lancair.list-request@olsusa.com>
Received: from pop3.olsusa.com ([63.150.212.2] verified)
  by logan.com (CommuniGate Pro SMTP 3.4.7)
  with ESMTP id 799961 for rob@logan.com; Fri, 15 Jun 2001 16:08:23 -0400
Received: from imo-r10.mx.aol.com ([152.163.225.106]) by pop3.olsusa.com
          (Post.Office MTA v3.5.3 release 223 ID# 0-71175U5500L550S0V35)
          with ESMTP id com for <lancair.list@olsusa.com>;
          Fri, 15 Jun 2001 13:55:10 -0400
Received: from RWolf99@aol.com
	by imo-r10.mx.aol.com (mail_out_v30.22.) id k.a8.16db43cb (4397)
	 for <lancair.list@olsusa.com>; Fri, 15 Jun 2001 14:03:07 -0400 (EDT)
From: RWolf99@aol.com
Message-ID: <a8.16db43cb.285ba7da@aol.com>
Date: Fri, 15 Jun 2001 14:03:06 EDT
Subject: Re: Powder Coating Aluminum
To: lancair.list@olsusa.com
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
X-Mailing-List: lancair.list@olsusa.com
Reply-To: lancair.list@olsusa.com

          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
          <<  Lancair Builders' Mail List  >>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> 
>>
In a message dated 6/14/2001 11:08:17 PM Pacific Daylight Time, 
lancair.list@olsusa.com writes:

<< Powder coating will not adhere to dirty metal.  Which means if all the
 corrosion isn't removed from the aluminum...>>

I had all of my control pushrod stock alodined professionally.  When I make a 
pushrod I whack off a piece, and the resulting pushrod is alodined inside and 
out (except for the edge at the end).  Presumably this is rustproof and 
clean, though I did have them solvent-wipe the aluminum before powder coating.

The control crossover weldment did have some surface rust on it in a small 
area (three square inches).  This part is cad-plated steel and I allowed them 
to lightly sandblast this before coating.  So presumably my parts are clean 
and rust-free when powder coated.

 <<There
 is absolutely no way to tell if you have a serious crack in the metal
 underneath the powder coat until the part fails or the coating cracks
 and breaks off to reveal the problem.>>

Interesting point, if true.  However, I'm told that the paint on our 
fiberglass parts is less resilient than the underlying structure, and that if 
you bang the part and there's no crack in the paint, you can be sure that 
there's no crack in the fiberglass.  While not necessarily relevant to powder 
coated aluminum, I wonder if it's possible to crack aluminum and not crack 
the coating?

 <<Vibration is the one operating factors that differ between bicycles and
 airplanes. >>

Yup.  It seems much worse on my bike....  (Just joking here)

Seriously, though, I do appreciate Curtis' and everyone else's comments on 
this.  I freely admit to not knowing any more about the effect of powder 
coating on aluminum beyond the obvious -- It looks much better when finished. 
 I'm not saying they're wrong, not at all, but if corrosion is the big issue 
then I think powder coat over alodine or a cleaned surface is fine.  I also 
think the environment in our airplanes is more benign than on the bottom of a 
car.

The issue originally raised, however, was loss of heat treatment due to brief 
exposure to temperatures above 400F.  Just curious here, but what are you 
guys going to do when you see a cylinder head temperature of 400F?  Scrap the 
jug?  I don't think so.  Isn't this the same issue?

- Rob Wolf

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
LML website:   http://www.olsusa.com/Users/Mkaye/maillist.html
LML Builders' Bookstore:   http://www.buildersbooks.com/lancair

Please send your photos and drawings to marvkaye@olsusa.com.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>