I'll try to have photos added later this year
FORMING THE NIPPLES
Try to work in a fairly dust-free environment. Dust and air bubbles can cause weak points in the nipple.
Dip a T-pin 3/4 of the way into the latex (about an inch and a half in depth).
Push the T-pin base into the modeling clay so it is standing upright.
Allow latex to dry for 8 hours (preferably overnight).
Repeat the dipping/drying process 2 more times (allowing each coat to dry overnight), so you have a total of 3 coats of latex.
Now that all 3 coats are fully dry, use your fingers to gently roll about 1/4 inch of the dryed latex onto itself to form the nipple rim.
Dip the nipple into the latex, coating the newly formed rim too. Allow the latex to dry overnight.
MAKE THE NEEDLE SUPPORT
While the nipples are drying, you can make the needle forms. The forms will be used to hold the aluminum needles while in the oven, to prevent the nipples from touching any surface. Use a block of polymer clay. Take one of the aluminum needles and make a slight depression on the top of the clay. The depression should be just deep enough to support the aluminum needle without letting it roll or fall off. Make several depressions on the clay, one for each needle (about 1 inch apart). Leave the needles in their position on the clay while drying. Follow the label instructions for drying the clay, or bake in the oven at 275 degrees for 45-60 minutes.
CURING THE NIPPLES
Once the nipples have dried overnight, you will need to transfer them to the aluminum needles. The aluminum needles are used to hold the nipples so that they can be properly cured. The diameter of the aluminum needles are also used to make the larger opening at the base so that the nipples can be put onto syringes or catheter tips. If you tried to cure the nipples while they were still on the T-pins, the base opening would be too small for a cannula tip or syringe.
Place all the latex coated T-pins in a bowl of water for about 20 minutes. The latex will reabsorb the water and turn milky colored. Now gently work the latex nipples off the T-pins. Slide the latex nipple approximately half way onto one end of the aluminum needle. Place another latex nipple on the other end of the aluminum needle and rest it on the needle forms you made earlier.
Preheat the oven to 185 degrees. Place the needles onto the needle forms on a cookie sheet and bake the nipples for approximately 4 hours. Be careful not to over dry them, otherwise they'll turn gummy. If you've under-dried them, they'll turn milky when they get wet. Once the nipples have fully dried and cooled, remove them from the aluminum needles and lightly coat them with corn starch. Keep them in a cool, dark, dry location until used. Glass amber-colored pill bottles are ideal.
The micro nipples can be placed onto a cannula tip, available from jeffers through the following link: Cannula Tips. If you've underdried the nipples they may not grip well. You can roughen up the surface of the cannula tip with sandpaper for better gripping power.
If you need a wider opening at the base, you can use larger aluminum needles. But avoid making them too wide or there could be too much milk flow which could result in aspiration.
If you have any tips to offer others, please be sure to add them to the comments section below.