seeker333

1mm is a pretty deep gouge considering the tubing wall thickness is only a bit over 1mm thick at the butts (the thick wall section at tubing ends where tubes are joined by welding or brazing). Wall thickness in the middle of the tube is often less than 1mm on road bikes.

This may be serious damage. You may want to have a professional framebuilder inspect the damage before powdercoating.

See the 631 tubing profile chart at this link, about a third of the way down the page. See the 1.2/0.6/0.9... I believe the units are millimeters!