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Now
that I have a vacuum table I need a frame to hold the plastic sheets of Kydex
and heat it in the oven (don’t tell my wife). I looked at using a picture frame
or any other type of frame that would hold the plastic on the edges, but allow
the center to freely hang down once heated and soft.
Again
going back to my plywood supply I made a cheap but effective double sided
picture frame. You can see in the bottom right photo above the frame sitting on
top of the vacuum table. It clamps down on the plastic by 8 screws and t-nuts
that are mounted around the perimeter.
OK now I have my plastic support frame, a vacuum table and
the plugs to mold my plastic on. I start by preheating the oven to 355 degrees Fahrenheit.
Next I cut a 12” square piece of .060” Kydex and clamp it in the frame. The
vacuum table is set up on my kitchen counter and the shop vac connected. I
place the plaster plugs on the table so that the holes are visible all around
the edges so it will get a good vacuum seal around the plug.
Now it is time to heat up the plastic. I place 2 bricks in
the oven to support the frame. Like the pillars of a bridge I place them 12”
apart and then place the Kydex load frame as a span between them so the plastic
can heat up and sag down.
I won’t go into the details of how long to heat the
plastic because there is a great article on the Kydex website about this. It is
located in the Technical Briefs Section and is the one on Thermoforming.
http://www.kydex.com/Technical/ShowArticle.asp?ArticleID=520
Now that the plastic is hot it is time to pull some
plastic! Once the plastic is hot and soft, drape it down on the table slowly
and get it centered. You will see the plastic start to fall and form around the
plugs. Now you must turn on the vacuum and let it run till it pulls the entire
sheet tight down on the table and plugs.
Here are some photos of the process: |