<VV> Paint, was: Comments to the Virginia DMV (humor) and the ForbiddenMentionof painting

[jvhroberts at aol.com]

 It's not the roughness that makes one layer of paint attach to another, it's the surface energy. Roughness simply increases surface area. 

Surface energy is a measure of the chemical reactivity of a surface, roughly speaking. Some examples of high and low surface energy materials:

Low:
Teflon. 
Polyethylene. 
Polypropylene.
Polyolefins in general
PET 

High:
PVC
Acrylics
Polycarbonates
Polyurethanes
Polystyrenes
ABS

Another factor loosely related to surface energy is polymer compatibility. Not all polymers, even if both are high surface energy, will stick to each other directly. Acrylics and nitrocellulose, even though both can be dissolved in similar solvents, want much to do with each other. 

Needless to say, this is a complex subject. 

For paints, the BEST advice is to follow the manufacturer's recommendations CLOSELY. Invariably, problems with painting WILL occur if you ignore what the manufacturer says. 



 


John Roberts

 


 

-----Original Message-----
From: Harry  Yarnell <hyarnell1 at earthlink.net>
To: airvair at earthlink.net; tony.underwood at cox.net; yenko117 at yahoo.com; jvhroberts at aol.com
Cc: virtualvairs at corvair.org
Sent: Mon, Sep 21, 2009 2:45 pm
Subject: Re: <VV> Paint, was: Comments to the Virginia DMV (humor) and the ForbiddenMentionof painting










Not knowing what 'surface energy' is, I figured that the relative roughness of 
the lacquer was enough 'tooth' for the Imron topcoat.
On another note, I painted (and still own) a '65 Corsa that I painted in an Art 
Artzburger paint scheme (stripes on the engine and trunk lids) with a black 
body; all in Dupont lacquer. Clearcoated in Imron.
This was maybe 25 years ago. Still looks beautiful.

Harry Yarnell
Perryman garage and orphanage
Perryman, MD
hyarnell1 at earthlink.net
  ----- Original Message ----- 
  From: jvhroberts at aol.com 
  To: hyarnell1 at earthlink.net ; airvair at earthlink.net ; tony.underwood at cox.net ; 
yenko117 at yahoo.com 
  Cc: virtualvairs at corvair.org 
  Sent: Monday, September 21, 2009 2:11 PM
  Subject: Re: <VV> Paint, was: Comments to the Virginia DMV (humor) and the 
ForbiddenMentionof painting


  Indeed, Harry! Imron requires the correct base to adhere to. Given that it IS 
a reactive, isocyanate containing polymer, it needs a surface with both active 
hydrogen groups AND reasonable surface energy. Neither acrylic or nitrocellulose 
lacquers meet these needs. Now, if you did Imron over Imron, life would be 
SWEET!



  John Roberts

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