it also turns out the vancafe has the original part! It's here:
http://www.van-cafe.com/home/van_1308609659930/page_1006_279/test_pipe_cap.html

When I called, they were happy to send it in a padded envelope through the
mail for a few bucks rather than what the website was quoting for UPS
shipping.

On Mon, Jun 20, 2011 at 7:26 PM, David Beierl <dbeierl@attglobal.net> wrote:

> At 06:49 PM 6/20/2011, Dennis Haynes wrote:
>
>> Run an 8X1.25 tap in it and use a bolt to plug it.
>>
>
> Or fifteen or so layers of heavy-duty aluminum foil and a hose clamp.
>
> Yrs,
> d
>