The difference between a proven shape and a custom one

A custom shape sounds like the better answer because it is the more specific one. In practice a proven shape that already has campaign history behind it will beat a first-run custom piece often enough that it should be the starting assumption, not the fallback.

The reason is that a proven shape carries information. It has been cast, cured, handled, installed and run, and every one of those steps has already found the problems that a drawing cannot show you.

Custom earns its place when the geometry genuinely does not exist in the catalogue, when the install method demands it, or when the wear pattern on the last campaign points at a profile change rather than a material change.

Every lining lives in a set of conditions before it lives in a vessel: the chemistry it meets, the thermal cycle it rides, the abrasion it takes at the wear face, and the access the crew gets when it is time to put a new one in. Change any one of those and the right answer moves.

What we look for is the point where the decision was actually made. Usually it was not on the shutdown floor. It was in a specification written months earlier, against an assumption about service conditions that has since moved.

The cost difference is rarely the deciding factor. Tooling is a real number, but the schedule impact of a first-run piece — the trial, the adjustment, the second run — is usually the bigger one, and it shows up at the worst possible time.

If you are working through this on a vessel of your own, the fastest way in is to bring us the conditions you run in — cycle, chemistry, access, and what failed last time. That is enough to have a real conversation about what to change.