Dave Rennie Posted September 17, 2015 Author Report Share Posted September 17, 2015 FYI. Cavity vents only need to be a few thousandths deep. I tend to go with .002 for blade vents and .003 for point vents. Then I dump them all into a deeper easier flowing main vent. Thanks Bob, are you talking inches there? What is a blade vent, and what is a point vent please? Quote Link to comment Share on other sites More sharing options...
Dave Rennie Posted September 17, 2015 Author Report Share Posted September 17, 2015 Just be aware that the biggest danger of injecting a top or side inject mold from the bottom is if you slip you will shoot molten plastic all over the hand holding the mold. I've got a wood worker's vise bolted to my pouring bench for testing any problem molds so my hands are not in the path of destruction. I stand as far back as I can work safely so if something goes wrong it won't run down my pants legs either. After the mold is full I just stand there and hold it for a good minute to make sure the mold sprue won't drip on me either. I would note that this is something I only do when testing a mold that doesn't fill right to see if syringing it will fix the problem. If it fixes the problem I recut it as a bottom inject mold like this. http://www.tackleunderground.com/community/gallery/image/8535-flipping-grub/ Thanks again. If all goes to plan, the mold and copper pipe will be contained inside a plastic box held in place with bricks or something similar, and the dowel will push through an almost perfect sized hole in top of the box. Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted September 17, 2015 Report Share Posted September 17, 2015 Thanks Bob, are you talking inches there? What is a blade vent, and what is a point vent please? Blade vents is all around or a large portion of the cavity. Point vent just vents a single point. Yes inches. Quote Link to comment Share on other sites More sharing options...
Dave Rennie Posted September 17, 2015 Author Report Share Posted September 17, 2015 Blade vents is all around or a large portion of the cavity. Point vent just vents a single point. Yes inches. Thanks Bob. Quote Link to comment Share on other sites More sharing options...
Cub48 Posted September 30, 2015 Report Share Posted September 30, 2015 I made a injector out of a shock for a lift gate on a Tahoe. If u know someone in the automotive field have them to save u some we change them often. The piston is aluminun with a oring the bore is smooth, it is design for pressure. i bought some aluminun rod that would fit tight for the tip i put a set screw in it to keep it from coming out. I have not thought about a tip made made of a wooden dowel but that would be a lot easier it has to be tight so it don't leak air. But the only thing would be if u heat your injector like i do the wood would burn. if u keep your injector warm after u shoot u can push out all your plastic and cycle if a couple times and blow the plug out so u don't have to clean it between shots. I used one of these for two years before i bought two from lurecraft. Only reason i changed was the ease of cleaning the injector as i am using dual injector for two colors now. PS, Only one of the shocks will work as the other has a place in the bore it still may work but i did not use it don't know why it has two different shocks but u can see the line in the outside of the shock. Cub48 1 Quote Link to comment Share on other sites More sharing options...
Dave Rennie Posted September 30, 2015 Author Report Share Posted September 30, 2015 Thanks Cub, That's a good idea. I'll be trying the wooden dowel idea like JR suggested first, as it looks simple. There's a Paul Adams video on YouTube using the same method, and he wraps the end of the dowel in aluminium foil to prevent burning. I've got a nice design drawn up for the mold now that will hopefully fill all the cavities, I've already made about 10 masters from polymer clay, but have changed my mind on the jig heads that I was going to have in place the mold at time of pouring. I need a bit of advise on this and will start a new thread soon. Quote Link to comment Share on other sites More sharing options...
JRammit Posted September 30, 2015 Report Share Posted September 30, 2015 Honestly i see no reason to mold the jig heads in For fishing, it is better to have them seperate anyway.... When it gets torn up, you only replace the body.... Plus you can quickly change colors without re-tying Quote Link to comment Share on other sites More sharing options...
Dave Rennie Posted September 30, 2015 Author Report Share Posted September 30, 2015 I know what you're saying, but I'd rather have my jig heads either part of the lure design (fish skull), or contained within the lure itself. I'm swaying more towards having the lead part of the jig head contained within the lure, I just want to figure out how to do this properly to make sure the lures swim straight and not spin like one did on a recent test with a top pour mold. Some of the lures I've made are tiny like a 1" Kopyto. In order to put 1.5g of lead in the head of the body, I need the lead to be slim and long, rather than a ball that protrudes out of the plastic. I need to make the mold for the jig heads before I make the mold for the plastics. Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted September 30, 2015 Report Share Posted September 30, 2015 You need to find a way to accurately "key" your jig in the same place every time. You mentioned an open pour. If its a wide open flat top mold maybe a piece of stiff wire bent to fit around the top of the mold with a tiny stop pinched on the wire. You slide the hook eye on the wire, and up against the stop. For the hook you can do something similar with a piece of rod or dowel with a notch for the hook to rest in every time. These EXACT methods may not work for your application, but hopefully they will get you started thinking along lines that will allow you to get a satisfactory result. 1 Quote Link to comment Share on other sites More sharing options...
mark poulson Posted September 30, 2015 Report Share Posted September 30, 2015 I made a injector out of a shock for a lift gate on a Tahoe. If u know someone in the automotive field have them to save u some we change them often. The piston is aluminun with a oring the bore is smooth, it is design for pressure. i bought some aluminun rod that would fit tight for the tip i put a set screw in it to keep it from coming out. I have not thought about a tip made made of a wooden dowel but that would be a lot easier it has to be tight so it don't leak air. But the only thing would be if u heat your injector like i do the wood would burn. if u keep your injector warm after u shoot u can push out all your plastic and cycle if a couple times and blow the plug out so u don't have to clean it between shots. I used one of these for two years before i bought two from lurecraft. Only reason i changed was the ease of cleaning the injector as i am using dual injector for two colors now. PS, Only one of the shocks will work as the other has a place in the bore it still may work but i did not use it don't know why it has two different shocks but u can see the line in the outside of the shock. Cub48 If you had a wooden tip, would you even need to warm the injector more than just putting it into the hot plastic for a few seconds? Quote Link to comment Share on other sites More sharing options...
Dave Rennie Posted September 30, 2015 Author Report Share Posted September 30, 2015 Thanks Bob, I did the method you mentioned with a spinner wire through the eye of the jig hook. That part worked fine. The problem I had was that the lure spun in the water rather than swimming straight. I think this was because the weight was positioned to the top / middle of the lure rather than directly in front or at the belly. This was a quick test with thin lead window strip wrapped around a jig hook. In all fairness I didn't have time to test the lure with a shop bought ball jig head, so I have no idea how the lure performs yet. What I want to achieve is pouring my own jig heads with lead, then inserting them into a multi cavity two part lure mold so the jig hooks are concealed. Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted September 30, 2015 Report Share Posted September 30, 2015 What I want to achieve is pouring my own jig heads with lead, then inserting them into a multi cavity two part lure mold so the jig hooks are concealed. Concealed? Am I missing something? How are you going to hook the fish, or is this more one of those playing with "sea kittens" kind of things. LOL Quote Link to comment Share on other sites More sharing options...
Dave Rennie Posted September 30, 2015 Author Report Share Posted September 30, 2015 Catch and release has gone one ethical step further here in the UK Quote Link to comment Share on other sites More sharing options...
Cub48 Posted October 1, 2015 Report Share Posted October 1, 2015 Mark u maybe right i will have to try the wooden tip and see. I heat the injectors so i don't have to take a part the injector between shots. The plastic will not harden in the injector if it is warm and u can push it out. I heat mine on a hot plate and it may get it hot enough to burn. A wooden tip would be easier to form than the aluminum one. I wanted some tips machined but i bought new injectors for what it would cost me for the machine work. I had 4 mold ports cut to 5/8 and a injector rod turned a 1/2 " it was $40.00 Cub48 Quote Link to comment Share on other sites More sharing options...
