In order to make the first half of the mold, you'll need a box to pour the liquid rubber into, which will also hold the part.
In this case, the part is a bit big by itself, so the box needs to be big, with plenty of room around the part for resin pouring channels and vents.
I'll get into channels and vents in the next few posts.
This box is made out of 1/2" posterboard, easily obtainable from your local crafts store (Michael's, etc), and is 16" square by 4" deep.
The box was glued together just with normal white glue, but you could use wooden toothpicks inserted at the joints to strengthen the box.
I didn't in this case, as a glued 4-corner box is usually strong enough to hold the liquid rubber as it cures.
Oh, and if you're going to be cutting posterboard by hand, I highly reccomend picking up the Xacto Board Cutter tool - it's $15, but highly worth it - you can use it to cut clean 90 and 45 degree cuts.
The first picture shows the empty finished box.
I cut holes in the bottom to fit the pegs on the back of the bezel (I removed the white plastic clips for this).
Having holes in the bottom is not normally a problem, as the edges of the bezel will be sealed off with modeling clay, and will be trimmed to match the shape of the bezel.
The second picture shows the bezel in the box, ready to be edged with clay.
The closer the part is to the bottom of the box, the less rubber you will need to pour to cover it.
You may notice that this box does not have a top - you won't need one.
When this first half of the mold has cured, the resulting piece will be flipped over, and will sit on the bottom of the box, face up.
The part will then be placed back into it's mold, and the other half of the mold will be poured on top of the back side, forming a complete 2-part mold.
I'll be scouring my local hobby shops tomorrow for the silicone RTV rubber I'll need, but being as I may need quite a lot, I may have to mail-order a small bucket's worth... and that'll take about a week.
