Beginner Questions about Core and Bobbin

We are two high school physics students trying to build the Tesla Coil at
http://www.e-etc-dot-com/electronics/hivolt/tesla/tesla.htm.  We have already
purchased all of the parts for the coil on this page and have everything
completed except the core.

We cannot find anybody who can supply the AMIDON EA-77-250 ferrite core and
bobbin.  We are hoping that a cast iron pipe and iron rod will substitute
for the core and bobbin.  Is this correct?  If not then what should we use.
What should be the dimensions of the core and bobbin.  We have tried
contacting the person who posted the page, but he did not write the page.
He found it elsewhere on the net and is not able to help us.

We don't really know for sure what the core and bobbin is.  We are guessing
that they are similar to a pipe and rod with the core (or rod) fitting
inside the bobbin (pipe) is this correct?

We are reaching the panic stage as the project is due Friday.  Any help you
could give would be greatly appreciated.

Thanks in Advance

Michelle and Ruth
Emporia High School Class of 2000!!!