Thu Apr 15 2021

Oven testing

Installed the new duct atop the oven. Much better fit and finish.

Ran a test. Looks pretty good. The temp from the rear thermocouple is displayed on the Fluke meter. Front thermocouple displays on the controller. Target range is 910-930 F.

After lunch, I solution heat treated a piece of 2024. This scrap strip was actually 2024-T3 already, but the spec doesn't state that a starting temper for solution heat treating, so this should be a fine test. The oven was still pretty warm from the prior test, and there was more temperature difference between front and back, but at this point, I think it's going to be good enough. The test strip didn't exhibit any blisters. I also found an article that described the effect of reduced SHT temperature on the material properties. Essentially, there will be ~7% reduction in strength if the temp is 10 C below the desired range. If it's necessary adjust the setpoint down at the front to avoid exceeding the high end of the SHT range at the back, I'll live with it.

I spent the rest of the day forming a new flange for the left side of the subpanel bulkhead. I'll SHT this tomorrow.