Hey Hawgbone,
I am not the best at injection, but these are some tips that I have received along the way that have been helpful to me.......
1st, lube your new injector with scent worm oil. Just a few drops goes a long way.
2nd, I personally like my injector hot. I use a hot plate that I purchased at walmart - turn it on 400 degrees and let the injector sit while heating the plastic.
3rd, plastic I don't know what type of plastic you're using, but soft is the most difficult to work with, then medium, then hard. Okay, this is a must an has been very helpful to me - an infrared temp gage! This will allow you to see how hot your plastic is. If using a microwave, I start off let's say 6-onces plastic well shaken, put in for 1 min then you can check with the temp gauge to see where you're at. Depending on temp you can go every 15 or 30 sec to bring it up to about 350. Make sure you stir the plastic before you check temp. Once at 350, add color and glitter, then stir it in. Then check temp again. If it drops below 315, put the plastic back in for about 5 -10 sec to bring it back up to 350.
4th - okay, time to inject. Take your hot injector off the plate and stick it in your cup of plastic, pull in all the plastic then eject all the plastic in the cup very slow. This will get rid of any air in the injector. Now pull the plastic in again and inject your mold - very, very slow, just rest your hand on the injector and it should flow right into the mold. Hold pressure on the injector for 10 seconds with the frog mold. Some molds are different than others, depending on how long you have to hold them on the end. Then top off the spru with the rest of the plastic.
I don't use the microwave much anymore, I use a presto pot. I find the presto pot easier to work with. Once you have more than a few molds that you're working with at a time, it is worth the investment.
I hope this helps. Good luck!
Shawn
Underdog Baits