Date: Tue, 22 May 2007 16:42:30 -0400
Reply-To: Bill Glenn <idahobill@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Bill Glenn <idahobill@GMAIL.COM>
Subject: Re: best t molding adhesive?
Content-Type: text/plain; charset=ISO-8859-1
On Tue, 22 May 2007 00:53:57 -0600, justin - <jtrashy@HOTMAIL.COM> wrote:
>any ideas on keeping the new t molding snug?
>
>how do i keep them from shrinking?
>
>thanks
>justin
>_________________________________________________________________
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The vinyl used for the extruded T-molding possesses a higher coefficient of
expansion than the plywood to which it was attached. The two materials
move at differing rates in response to temperature changes. Molding cut to
fit at 70 degrees will increase considerably in length when the interior of
the van is much hotter, and the molding will shorten considerably when the
interior of the van is colder; the plywood, having a lower coefficient of
expansion, is more stable over the same temperature range. The vinyl
molding, while quick and easy, and thus efficient from a manufacturing
standpoint, is essentially not suitable for an environment subject to such
a wide temperature range, without some provision for accommodating
expansion.
Further, due to the aging of the vinyl and the consequent loss of
resiliency, the molding can take a set, locking in the wrinkles that may
have formed, and over time, it seems that the molding always comes up short
as well. Look around your Westy, and see if that's not true. Probably the
only time the molding ever looked good was when it was new, and viewed when
at the same temperature as when it was cut to size at the factory.
The replacement molding will suffer from the same limitations, and no
amount of glue will overcome the basic physics in play, at least not long-
term. Also, on the replacement molding that I have used, I have found that
the leg of the T, the part that inserts into the kerf, is slightly narrower
in section than the original molding, and does not grip the kerf as well,
thus the molding sometimes works it way loose. I have had some success
with folding a piece of duct tape or electrical tape over this leg as a
shim to make it fit tighter, but it's not really a solution. I re-adjust
some of the more-visible pieces from time to time, and otherwise just live
with it.
How's that for a long answer to your question, without providing a solution?
Anyone else?
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