Hi Karl,
You have not explained what you want to do.
I suspect that you want the borders to continue down to the bottom
even thought the data may have ended in the top third of the page.
Anything along those lines is going to require extra work on your
part. The following would work, and might mess you up at a later
date.
Turn on Borders for all cells (so you will see them when printed).
Use print preview, and return to the spreadsheet
Look on your spreadsheet around row 50 for a dotted line for a border
Select cell above that line that includes right most data, then make
the selection from that cell to cell A1
File, print area, set print area
check with Print Preview, and if okay
File, print
when finished: file, print area, clear print area