When repairing combustion hardware on high temperature turbines (over 2350degs F), do you recommend removing the bond coat down to the base metal? Ive reached out to various vendors and most recommends removing to the base metal and others feel that applying TBC to the bond coat will suffice. What are your thoughts?

With hotter temps in the combustion section, it would be wise to remove the bond coat so the TBC adheres better. Ive had experiences where TBC spallation is severe after poor bonding on existing base coats. If the turbine burns at lower firing temps, I think the spallation is not as much of an issue. Also operating on liquid fuel is more damaging to your components as opposed to gas fuel.

All of the repair facilities recomend stripping down to base metal and recoating. Weve had spalling problems as well and it isnt worth the risk of lossing a part and pieces going downstream. This can happen quickly after the TBC is gone.