The final step in the process is bagging the part and applying vacuum and heat. The bag is basically heavy-duty clear plastic that can withstand the temperatures we're applying without melting. The base plate is steel and has had mold release applied just to be safe. The yellow stuff is sort of a gooey weather stripping that creates an airtight seal. The vacuum hose is attached to a fitting that pokes through a small hole in the plastic bag. You can see how the bag is pulled tight to the plug.

This is the oven. The grey motor towards the left is the vacuum pump. The stuff to the right side is a temperature controller and a plotter showing the ramp-up in temperature and the hold time. The box is very well-insulated. With the temperature sustained for ~2 hours at 250-275 degrees F, the outside of the box never got above room temperature.

Here's a close-up of the plotter. You can see the graph from a past baking session. The temperature ramps up 1 degree per minute and then sustains 250-275 degrees for 1-1/2-2 hours and then lets the temperature decrease at a rate of 1 degree per minute until it reaches room temperature again.

The little black instrument on top of the box is the temperature controller. It's what turns the heater on and off to allow the temperature to rise and fall at 1 degree per minute--and to sustain the pre-set temperature for the pre-set time.

The timer mounted next to the plug-in is for the vacuum pump. We set the pump to run for the predicted time of the temperature cycle. The vacuum is maintained on the part all the way through the heating/cooling process.

Here is the "lid" just after it came out of the oven. I've removed the vacuum bag, but nothing else. You can see how the batting absorbed a bunch of resin as the part was heated and squeezed.

This is the "lid" after most of the peel-ply was removed. My friend is grinding excess resin out of the threads in the stainless fitting we glassed in place. We forgot to fill the stainless fitting with clay so it took a little careful grinding and a quick pass with a tap to clean the threads.

You can see how well the glass cloth sucked down over the foam core. The foam core creates a structure that is roughly twice as strong and half the weight as using additional layers of cloth to achieve the same strength.