[TheForge] Unique (?) coating for steel and iron...

Tue Apr 13 11:29:00 2004

Your last bit hits on the real possible problem -- the reason foil was used
in the packaging was that the poly itself was very poor at preventing the
movement of air and water through the packaging.  This might still be the
issue for a true weather proof coating.  (This remains as the major problem
with putting beer in plastic bottle -- i.e. poor shelf life.  I know it has
been done -- but doesn't sell worth a damn.)

On you other point -- for us in the laminating operation it was animal fat
that was the problem.  Not the petroleum base oil used in rolling.  The
petroleum was all driven off in the annealing furnace but the film strength
additive -- butyl stearate -- made from animal fat was the killer.  It made
up about 5 percent of the rolling "oil".

Dave
----- Original Message ----- 
From: "Bruce Freeman" <[email protected]>
To: <[email protected]>
Sent: Tuesday, April 13, 2004 8:29 AM
Subject: Re: [TheForge] Unique (?) coating for steel and iron...

> Dave,
>
> With the process you describe I can see that oil would be a problem.
> You were probably working at just the proper temperature for best melt
> and adhesion.
>
> With the hot-melt glue on iron, however, I think one would be working
> well over the melting point of the glue.  Hence, the glue would act as a
> solvent.  Finger oil might be problematic (it's not "oil" in the sense
> petroleum is- at "best" it's "animal fat") but I expect most oils would
> simply mix with the molten glue.
>
> The real question is whether the resulting coating is sufficiently
> impervious to water and air as to preclude rusting.  Time will tell.  My
> project was a boat hook - for salt water use!
>
> Bruce
>
> >>> [email protected] 4/12/2004 1:12:58 PM >>>
> Bruce,  Don't see any reason your idea shouldn't work well.  In another
> life
> I spent a lot of time working with applying a film of hot polyethylene
> to
> aluminum foil or to aluminum foil on one side and paper on the other.
> The
> hot poly came from a extrusion head, it started as small beads of poly
> and
> was melted and extruded under pressure from a heated power screw.  The
> film
> die was also heated.  The only real key was that the aluminum surface
> had to
> be very free of oil.  Oil in this case came from the rolling process.
> With
> clean hot iron this should not be a problem provided you don't get oil
> from
> you hands on it.  It should be worth a try and might work well out in
> the
> "weather".
>
> Dave Smucker
>
> ----- Original Message ----- 
> From: "Bruce Freeman" <[email protected]>
> To: <[email protected]>
> Sent: Monday, April 12, 2004 10:27 AM
> Subject: [TheForge] Unique (?) coating for steel and iron...
>
>
> > I've been sitting on this idea a few weeks in hopes of being able to
> > test it thoroughly.  Lack of time has precluded that.
> >
> > Here's the background:  While welding a polyethylene doohicky, using
> a
> > polyethylene coffee can lid as my "stick" and an old cast iron spoon
> ash
> > my iron, I noticed what a nice coating of polyethylene I got on the
> > iron.  Aha!  A water-impervious coating for iron, cheap as recycled
> > garbage...
> >
> > Well, it turns out that polyethylene melts at about 380 F, and burns
> > not much higher than that.  So, while, in principle, it could be
> used
> > fairly nicely, it's not to practical.  You're have to tow the line
> > between something moving slower than molasses, and something burning
> > like napalm.  If you could apply the polyethylene to the iron under
> > strict (~400 F) temperature control, this would probably work.
> >
> > However, while contemplating this, it occurred to me that hot-melt
> glue
> > is nothing more than low-MP polyethylene, or high-MP paraffin wax,
> with
> > a MP of~200 F or less.  So I tried applying this to a recent project
> and
> > it seems to have worked quite well.
> >
> > So there you go.  Get your metal to ~250 in an oven and rub the
> > hot-melt glue stick directly on the thing. Smooth with a cloth or
> brush
> > (vegetable fiber - not bristle or synthetic).
> >
> > Next I have to test how effective it is.  Or wait for one of you
> guys
> > to test it and let me know.
> >
> > Bruce
> > NJ
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