southernmost Posted May 2, 2018 Report Share Posted May 2, 2018 Hey everyone, I recently bought a top injection mold from Basstackle and have been shooting with Bait Junkies, now Bait Plastics' hard formula. I cannot for the life of me get a bait to shoot without there being air bubbles at the top/head of the bait. It's infuriating! I haven't violently stirred the plastisol or sucked up any air while pulling plastisol into the injector, but it happens nearly every time I inject. The reason I know I'm not doing this is because I have another, side inject mold from a different company that shoot perfectly every time. I've tried purging the injector prior to shooting and that didn't work. Anyone have another idea on how to fix this issue? Is it the mold sprue that is the problem. I can't help but notice that the side injection mold that shoots perfectly has a wide sprue opening where it meets the body of the lure, whereas the Basstackle top inject mold has a very narrow sprue-body connection. Could air be getting trapped at that choke point and not be allowed to escape? Any advice you have would be greatly appreciated. Thanks for your time and help. Quote Link to comment Share on other sites More sharing options...
alsworms Posted May 2, 2018 Report Share Posted May 2, 2018 Have you tried using the search function? This topic has been discussed many times before. For some reason, the upper left hand search button is not working, but hover over activity in the upper right portion, click on search, and type in "bubbles" or "bubbles in plastic". Hopefully, you will find your answer there. Quote Link to comment Share on other sites More sharing options...
Bassinfool Posted May 3, 2018 Report Share Posted May 3, 2018 Top inject can be tricky. You may need a sprue extender. Quote Link to comment Share on other sites More sharing options...
Frank Posted May 3, 2018 Report Share Posted May 3, 2018 I have a bunch or there top inject molds and some are different than others. For the ringed ones I use the Twinjector all the time even if it is one color. And it will bubble towards the top when the plastic is to hot. Cool your plastic to about 300-310 and inject slow when you feel it stop give it a bit of a quick push and remove the injector. Now here is something that I have found is when shooting a cold mold it will have a tendency to pull the Sprue out and let air in. Air will be in the tip or nose of the bait. On others molds like the shad body’s I shoot hotter with the same push at the end to force out air trapped toward the top of the mold. Hopefully this will help if not repost what mold you are talking about and I will see if I have any tricks on those. 1 Quote Link to comment Share on other sites More sharing options...
The Plastics Man Posted May 30, 2018 Report Share Posted May 30, 2018 (edited) I have found that some top inject molds do not like to be clamped but some do. I have a mold from BT in various sizes and one requires to be bolted using the provided hardware where as another size/s can be easily shot using clamps. Put it down to where the bolts are positioned in relation to the breathing channels. Clamping over the channels will produce a bad shoot with one little chin bubble just below the sprue and unintentional eye sockets. Try using different injection pressure. Edited May 30, 2018 by The Plastics Man Quote Link to comment Share on other sites More sharing options...
MonteSS Posted May 31, 2018 Report Share Posted May 31, 2018 Sounds like air pockets and not bubbles. As said either get/make a spru extender or baby sit the mold and keep topping it off as the level goes down. If it is not sucking down then the gates are too small and closing (cooling) and not allowing the plastic in the spru to be used. 1 Quote Link to comment Share on other sites More sharing options...
