Copy Blob data into Varchar2

Can someone share any function which can allow to insert BLOB data into Varchar2 column? Most of the BLOB data is less than 32K but selecting the BLOB using dbms_lob.substr( l_cur.mylob, 32000, 1 ) or utl_raw.cast_to_varchar2 gave error ORA-06502: PL/SQL: numeric or value error: character string buffer too small

Can someone share an example to convert data from BLOB to varchar ? TxSanjay

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