By Lawrence 
Date 10-06-2008 17:39
Edited 10-06-2008 18:04
AerotigMan, Welcome to the forum by the way!
Hush Kits!
This one is right up my alley :) Having done thousands of crack repairs on Hax-X flame holders, seals, turkey feathers and combustion cans.
While a bit muddy and sluggish as far as weld pools go, Has-X should be a walk in the park once you get your process under control.
Preheat is not an issue for Has-X especially less than .125" in thickness.
Cleaning to brite metal may be recommended for initial fabrication but is not good enough for a repair work on an oxidized hot section. A 1" 80-120 grit, silicon carbide disc driven by a pnumatic angle grinder does a good job of oxide removal.. Mechanical removal of surface oxides on both sides of a defect is a must for Hax-X hot sections... Bead blast is *always* preferable when the componant is off wing. Wire brushing to bright metal is inadequate.
Has-X crack repair requires 100% routing of defects (stop drills and dye penetrant check to verify crack ends are a common procedure). Even the tightest cracks are full of bad stuff and if you try to route just part of the crack or to boil them out without routing the crack, the defect will simply reform when the pool freezes and will be visible when blending the welds flush. There are no short cuts here... The routing of defects are often the cause of distortion when the reweld takes place and restraining fixtures with gas backups may be required in order to stay within dementional tollerences.
A very thin cutting wheel on cans or seals, or a ball burr less than 1/8" and a high speed die grinder (80-100K rpm, depending on the rating of the burr) are good options for defect removal depending on the surface.
Argon backup is also a requirement when making full pen welds and suggested even partial pen welds less than .063
This type of repair data should be available to you via your company or vendor standard practice manual and general notes (GN's)
