diff --git a/onshape_to_robot/onshape_api/client.py b/onshape_to_robot/onshape_api/client.py
index 353d28b..c241ccd 100644
--- a/onshape_to_robot/onshape_api/client.py
+++ b/onshape_to_robot/onshape_api/client.py
@@ -14,6 +14,9 @@
 import json
 import hashlib
 
+def escape_slash(s):
+    return s.replace('/', '%252f')
+
 class Client():
     '''
     Defines methods for testing the Onshape API. Comes with several methods:
@@ -323,18 +326,18 @@ def invoke():
             req_headers = {
                 'Accept': 'application/vnd.onshape.v1+octet-stream'
             }
-            return self._api.request('get', '/api/parts/d/' + did + '/m/' + mid + '/e/' + eid + '/partid/'+partid+'/stl', query={'mode': 'binary', 'units': 'meter', 'configuration': configuration}, headers=req_headers)
+            return self._api.request('get', '/api/parts/d/' + did + '/m/' + mid + '/e/' + eid + '/partid/'+escape_slash(partid)+'/stl', query={'mode': 'binary', 'units': 'meter', 'configuration': configuration}, headers=req_headers)
 
         return self.cache_get('part_stl', (did, mid, eid, self.hash_partid(partid), configuration), invoke)
 
     def part_get_metadata(self, did, mid, eid, partid, configuration = 'default'):
         def invoke():
-            return self._api.request('get', '/api/parts/d/' + did + '/m/' + mid + '/e/' + eid + '/partid/'+partid+'/metadata', query={'configuration': configuration})
+            return self._api.request('get', '/api/parts/d/' + did + '/m/' + mid + '/e/' + eid + '/partid/'+escape_slash(partid)+'/metadata', query={'configuration': configuration})
 
         return json.loads(self.cache_get('metadata', (did, mid, eid, self.hash_partid(partid), configuration), invoke, True))
 
     def part_mass_properties(self, did, mid, eid, partid, configuration = 'default'):
         def invoke():
-            return self._api.request('get', '/api/parts/d/' + did + '/m/' + mid + '/e/' + eid + '/partid/'+partid+'/massproperties', query={'configuration': configuration})
+            return self._api.request('get', '/api/parts/d/' + did + '/m/' + mid + '/e/' + eid + '/partid/'+escape_slash(partid)+'/massproperties', query={'configuration': configuration})
 
         return json.loads(self.cache_get('massproperties', (did, mid, eid, self.hash_partid(partid), configuration), invoke, True))
diff --git a/onshape_to_robot/onshape_api/onshape.py b/onshape_to_robot/onshape_api/onshape.py
index 202d99a..82eb41d 100644
--- a/onshape_to_robot/onshape_api/onshape.py
+++ b/onshape_to_robot/onshape_api/onshape.py
@@ -221,6 +221,7 @@ def request(self, method, path, query={}, headers={}, body={}, base_url=None):
 
             return self.request(method, location.path, query=new_query, headers=headers, base_url=new_base_url)
         elif not 200 <= res.status_code <= 206:
+            print(url)
             print('! ERROR ('+str(res.status_code)+') while using OnShape API')
             if res.text:
                 print('! '+res.text)