The moment of molding has arrived! Measure your chosen putty by making equal sized balls. Silicone mold putty is very forgiving so you can add more putty after the first batch sets if you underestimate the amount you need. If you tend to measure generously, have a few extra items around to make interesting mold shapes with in case you have extra putty. Beads can be cast to make clear bottle caps, short thick lengths of wire that match the top of your bottle can be made in case you need extra necks. If you read through all the instructions before you start, I'll show you a few useful things you can cast in extra putty.
Have All Your Mold Materials Ready- Before you start mixing, check the set up time given for your mold putty, and have everything you need handy, including a thin flexible 'persuader' that can help slide stuck putty down into a tight container by forcing the putty away from the edge (a knife blade, a piece of stiff plastic or a glue spreader work fine).
Mix Your Putty - When you have equal amounts of putty measured out (with each color roughly able to fill half of your mold container), mix the two putties together thoroughly so that the colors are completely blended and there are no streaks.
Fit Your Putty Into The Mold Container - Take your mixed putty and gently push it into your mold container, trying to leave a path on one side of the container for the air to escape before it gets trapped by the putty. If the putty traps air, use your 'persuader' to make a gap along the wall of the container so the air can escape (clear, straight walled plastic or glass containers are great for your first attempts!) Make sure the putty reaches the top of the container (if it doesn't, just live with it for now.) If you have extra putty, set it aside and grab some of your extra objects to mold (pen caps, bottle caps, beads, charms (on one side) whatever will use up extra putty in the time you have before it sets up.)
Set Your Master Shape Into the Mold Putty - As soon as you have your mold container filled with putty, carefully insert your master shape into the center of the putty, preferably narrow end first so the putty grips tightly to the master shape. If you are using modelling clay to hold the master shape, insert the shape up to the mark you made for the bottom of the bottle, pressing the end into the clay level you determined by making your mark even with the top of your mold container. Make sure the putty is tight to the end of the master shape you can see, and that the master is straight up and down in the mold container. Leave it to set or hold it in place while it sets (without moving it!) Once you have your master shape inserted you can use your extra putty (if you have any) to make small molds.
If You Didn't Mix Enough Putty - Leave your first batch to set up firm, then mix another amount to work into the mold container on top of the first batch. Be careful to make sure that the putty is tightly pressed against the master shape. Leave the second batch of putty to firm up.
Silicon mold putty is hard enough to remove from your mold container when you can't make an imprint in the putty with your finger nail. Do not move your master shape or the putty, until the putty is completely set (usually just a few minutes).