I am refinishing the top of an oak buffet and have used wood filler to
cover many inperfections- problem is now that the stain will not cover
the wood filler and looks odd- creating darker areas etc where I put
the wood filler. How can I fix the top without having to put a whole
new piece of oak on it.

You might consider an oak veneer. It would be easier than redoing the
top and can be stained to match. Flexwood sells a pre-backed veneer
that you can peel-n-place and then sand and stain to match. It works
good and does not require extra tools and glue.

kariecarico wrote:
I am refinishing the top of an oak buffet and have used wood filler to
cover many inperfections- problem is now that the stain will not cover
the wood filler and looks odd- creating darker areas etc where I put
the wood filler. How can I fix the top without having to put a whole
new piece of oak on it.