I don't think that is going to be easy to pull off.
So let's say you do a search for "1 inch plastic"
How would the code know to look for "1 inch" in one column and "plastic" in the other? What not "1" and "inch plastic"? or "1" and "inch" and "plastic"? What if it finds the entire string "1 inch plastic" in the first table? What about the second? What if they type "plastic 1 inch"?
You are going to have to somehow identify what to look for in each column and what the rules are when searching. You might want to just add two fields instead of one.