chester_fb Posted July 29, 2012 Report Share Posted July 29, 2012 Hey guys I recently bought a 10 cavity 4 inch grub injection mould It is the first injection mould I have used. The problem I am having is that some of the grubs are coming out hollow or only partially formed. So I'm wondering what I am doing wrong, pouring to fast? Too slow? Mould is too cold? Thanks in advance Josh Quote Link to comment Share on other sites More sharing options...
pieterbez Posted July 29, 2012 Report Share Posted July 29, 2012 You need to fill up the spruce with plastic after you injected the mold. this should solve the hollow issue Quote Link to comment Share on other sites More sharing options...
chester_fb Posted July 29, 2012 Author Report Share Posted July 29, 2012 Sorry but probably silly question, spruce? As in the part where I inject the plastic Into? Quote Link to comment Share on other sites More sharing options...
pieterbez Posted July 29, 2012 Report Share Posted July 29, 2012 You need to fill up the spruce with plastic after you injected the mold. this should solve the hollow issue Sorry for the double post. The spruce is where you inject the plactic Quote Link to comment Share on other sites More sharing options...
smallmouthaholic Posted July 29, 2012 Report Share Posted July 29, 2012 Hey guys I recently bought a 10 cavity 4 inch grub injection mould It is the first injection mould I have used. The problem I am having is that some of the grubs are coming out hollow or only partially formed. So I'm wondering what I am doing wrong, pouring to fast? Too slow? Mould is too cold? Thanks in advance Josh Are you running out of plastic befor the injection port is filled to the top? If so,you need a larger injector capacity. BTW- who's mold is it and make and viscosity of plastisol you are using ? 1 Quote Link to comment Share on other sites More sharing options...
chester_fb Posted July 29, 2012 Author Report Share Posted July 29, 2012 The injector is large enough, I still have about half the tube left when im finished. It is a delmart mould and injector, Im not sure on the make and viscosity of the plastic I am using. cheers Quote Link to comment Share on other sites More sharing options...
smallmouthaholic Posted July 30, 2012 Report Share Posted July 30, 2012 (edited) There is the possibility you're getting air into your injector due to a faulty "O"ring seal. Make sure your plastic temp is 325- 340 degrees and check w/ an IR thermometer. Do your finished grubs dry soft and flexible or are they hard? If possible take a pic of both sides of the open mold and post. You want to inject s-l-o-w-l-y and evenly w/ you hand pressure and stop when you feel resistence.You should feel no changes or sudden drop in the plunger while your mold is filling BTW- why don't you know the type,hardness and source of your plastisol? Edited July 30, 2012 by smallmouthaholic Quote Link to comment Share on other sites More sharing options...
