Mark D., Tyler G., Chandra R., Kyle R. 

Gerardo M. and I had previously found a leak on the newly installed chevron baffle spool-to-valve flange.  Today I was able to vent IP1 and decouple the leaking flange and inspect it.  At the site of the leak, there was evidence of damage to the spool's knife-edge.  This "feature" is characteristic and typical of a flange fastener (stud in this case) having dragged across the knife edge during the flanging process when the two flanges are close but not in contact with each other.  I can't say for certain but this likely could have been prevented had all of the studs been removed prior to bringing the two mating flanges together.  Another abnormality was that the imprint of the knife-edge into the gasket material was very shallow in the region of the gasket corresponding to that which couldn't be brought "metal-to-metal".  Gerardo will say more on this in his entry.  

I consulted Chandra R. and we decided to attempt an in-situ "stoning" of the damaged knife edge.  John W. had shown me this technique years ago and I have successfully repaired many "dinged" flanges using this approach.  This entails finding a donor flange of the same size in the recycle bin and using it to pre-condition an abrasive stone such that arcs can be worn into it which match the knife-edge of the flange to be repaired.  I then wet-stoned (using IPA) the damaged knife edge which removes the displaced material and restores the cross-sectional profile of the knife-edge (minus the displaced, now removed, material). 

During the re-flanging following the repair attempt, I noticed that the new gasket fit loosely in the gate valve's flange.  I tried a gasket from a different manufacturing batch and it too fit loosely.  It looks like the tolerances are not standard in the valve's machining or are looser in the OD than typical at the very least.  How loose?  I didn't measure but would guess that the center of the gasket could be off as much as 0.040" from the valve's bore in any direction. 

Anyway, I re-flanged, pumped down and helium leak tested the new joint.  It looks good initially but I am leaving the leak detector connected and running overnight and will continue at the next available opportunity.