Mon Feb 08 2021

Sub panel top flanges

The son of a friend of mine was over today...he's thinking of going into mechanical engineering as a career. I showed him how to do bend calculations and we made this little tool in the process.

It is used to check the position of the canopy skin prior to positioning the sub panel top flanges for drilling to the sub panel. Looks good on the left...

...and on the right.

I set one of the two outboard flanges in the oven and propped it up on some bent strips of metal.

Heating cycle completed and quenched in this pan of water.

Arg...blistering on the end of the part again.

The end of the part with the blisters was the part sticking further into the oven. Looking at the (previously) bent strips of aluminum, the ones further in are more or less as flat as a pancake. I think the heat distribution in the oven isn't uniform. I'm speculating that further in is getting quite a bit hotter than near the door. That would make sense since the heating elements go down the sides and across the back, but the door has no heating element. The door is also where the thermocouple is for the controller.

You can alos see another problem I'm having with the oven...the heating elements are shrinking back to a shorter length, thereby pulling themselves out of the grooves. They end up sagging down at the back of the oven. I'm going to need to do something about this.

In the interest of troubleshooting, I wanted to check if it was just the radiant heat that was causing the part to get too hot, so I built this little hood to prevent direct radiation from the heating elements on the part.

Going to do a test with this scrap part.

Ready for solution heat treating.

While that was cooking, I decided to sharpen my snips. Disassembled them and ground the edges. They're just a joy to use now. :-)