[cenamus]

The work hardening when machining titanium is also just brutal, worse than stainless

[nocoiner]

Wasn’t there also some issue with water when the A-12 or SR-71 was being built? Like the local water treatment plant started fluoridating the water or something, and it completely screwed up the production process?

[kerkeslager]

"Completely screwed up the production process" seems a bit overstatement: with the budgets at stake for these projects, adding a distillation step to the water isn't some massive financial burden.

[nocoiner]

Fair enough! I think the primary issue was that for a while, no one had any idea why previous processes just stopped working. But my recollection of this is obviously hazy at best.

[Grosvenor]

Yes. They had to scrap tons of parts until they figured it out.

iirc they had to add the impurity back IN to get the process working again.