diff --git a/sqlmodel/main.py b/sqlmodel/main.py
index 08eaf5956f..0b9bff3bde 100644
--- a/sqlmodel/main.py
+++ b/sqlmodel/main.py
@@ -151,7 +151,8 @@ def Field(
     primary_key: bool = False,
     foreign_key: Optional[Any] = None,
     nullable: Union[bool, UndefinedType] = Undefined,
-    index: Union[bool, UndefinedType] = Undefined,
+    # NOTE: Undefined not propagating well to postgres - explicitly set False
+    index: Union[bool, UndefinedType] = False,
     sa_column: Union[Column, UndefinedType] = Undefined,  # type: ignore
     sa_column_args: Union[Sequence[Any], UndefinedType] = Undefined,
     sa_column_kwargs: Union[Mapping[str, Any], UndefinedType] = Undefined,
diff --git a/sqlmodel/sql/sqltypes.py b/sqlmodel/sql/sqltypes.py
index b3fda87739..a9f53ad286 100644
--- a/sqlmodel/sql/sqltypes.py
+++ b/sqlmodel/sql/sqltypes.py
@@ -47,10 +47,10 @@ def process_bind_param(self, value: Any, dialect: Dialect) -> Optional[str]:
             return str(value)
         else:
             if not isinstance(value, uuid.UUID):
-                return f"{uuid.UUID(value).int:x}"
+                return uuid.UUID(value).hex
             else:
                 # hexstring
-                return f"{value.int:x}"
+                return value.hex
 
     def process_result_value(self, value: Any, dialect: Dialect) -> Optional[uuid.UUID]:
         if value is None: