Saws taking a long time with last bits of balsa wood (6)
I believe the answer is:
adages
'saws' is the definition.
('adage' can be a synonym of 'saw')
'a long time with last bits of balsa wood' is the wordplay.
'a long time' becomes 'ages' (I've seen this before).
'with' means one lot of letters go next to another.
'last bits of' indicates one should take the final letters.
The final letters of 'balsa wood' are 'ad'.
'ages' after 'ad' is 'ADAGES'.
'taking' is the link.
(Other definitions for adages that I've seen before include "Much-used wise sayings" , "Old sayings or maxims" , "Maxims, saws" , "Aphorisms" , "Proverbs, wise sayings" .)