diff --git a/tailbone/forms/core.py b/tailbone/forms/core.py
index 5e079085..04633bbb 100644
--- a/tailbone/forms/core.py
+++ b/tailbone/forms/core.py
@@ -213,9 +213,17 @@ class CustomSchemaNode(SQLAlchemySchemaNode):
         excludes = []
         if isinstance(prop, orm.RelationshipProperty):
             for next_prop in prop.mapper.iterate_properties:
+
+                # don't include secondary relationships
                 if isinstance(next_prop, orm.RelationshipProperty):
                     excludes.append(next_prop.key)
 
+                # don't include fields of binary type
+                elif isinstance(next_prop, orm.ColumnProperty):
+                    for column in next_prop.columns:
+                        if isinstance(column.type, sa.LargeBinary):
+                            excludes.append(next_prop.key)
+
         if excludes:
             overrides['excludes'] = excludes