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Socal399

2 inch grub mold help

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I recently purchased a used aluminum mold off eBay and when I inject the plastic the tails aren’t coming out fully. It’s like the plastic is not making it far enough in.not sure if it’s the mold that’s the issue or if I’m calling it too right but Not sure what to try next. Here are some pics hopefully that will show better what I mean. Any help would be truest appreciated 

93BA6948-7FDA-44CA-BF90-5FF8BFECB8F0.jpeg

21457B73-8C82-44A3-8220-D430D043BC17.jpeg

4B136443-8600-4FC4-8637-5BAF89E3EE9E.jpeg

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Its very hard on thin tail stuff to displace air with little venting. IM the tail needs to be vented much better to allow the plastic to fill before it can cool.

 

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2 minutes ago, Baitjunkys said:

Its very hard on thin tail stuff to displace air with little venting. IM the tail needs to be vented much better to allow the plastic to fill before it can cool.

 

Do u think there’s a way to fix this mold or am I wasting my time 

Edited by Socal399

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9 minutes ago, Socal399 said:

Do u think there’s a way to fix this mold or am I wasting my time 

it may just be you arent starting with hot enough plastic, but more likely you just need to warm the molds first.

whats happening is the plastic is cooling too fast and getting hard, or you arent holding pressure on the injector so it fills completely.

as for fixing the mold, all you have to do is ,make the vent lines for the tail slightly bigger.

with that mold just find a small drill bit just a little bigger then the hole and drill it out one size bigger. dont go crazy with it, only use one size bigger, then if needed be go up one more size. you dont want it any bigger then it needs to be

Edited by keakar
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I would warm the mold, take a cotton swab and cooking oil and lube the tails, inject holding some pressure for a bit and see how it goes before I did any mold modifications.

That is how I get my baby brush hog and twin tail grub molds to shoot.

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4 minutes ago, Jig Man said:

I would warm the mold, take a cotton swab and cooking oil and lube the tails, inject holding some pressure for a bit and see how it goes before I did any mold modifications.

That is how I get my baby brush hog and twin tail grub molds to shoot.

thanks to everyone for the help gonna try this first before filing the mold for sure. What is the best way to preheat the molds? 

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29 minutes ago, Jig Man said:

I would warm the mold, take a cotton swab and cooking oil and lube the tails, inject holding some pressure for a bit and see how it goes before I did any mold modifications.

That is how I get my baby brush hog and twin tail grub molds to shoot.

+1 = warm/heat that mold up - that should help and I'd do that first before touching anything.  Maybe also shoot you plastic a little hotter as well.

If you need to open up the vents - I'd suggest clamping mold shut - then using a reasonable size drill bit to drill down the current vent hole BUT - do not go into the cavity - stop to about 1/8" - 1/4" from the cavity.  You can then use a file to open the vent little by little till it works.  MUCH easier to file open 1/8" - 1/4" of material away than the whole long vent.  I'd make the last vent on tail the largest.

Between heating and opening up the vent - you'll fix that mold.

  J.

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You should never have to heat a mold to shoot it. If it is vented properly, it should take the plastic with zero resistance. Injector should never have feed back till it is full. If it does, your fighting back pressure which causes issues. That bait with that short tail should easily shoot at 315- 320....

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Blow on one of them cocktail straws and see how easy it is. Than blow thru a std straw, it is very self explanatory from there.

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Can also try injecting faster, I have a mold with thin tails and it doesn’t fill the tails with my normal slow injection speed, inject fast and it fills perfectly 

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A vent that is a little too big is a pain, because you have to trim the tag that's left, but a vent that's too small is a nightmare, because you wind up with incomplete baits that have to be remelted and poured again.

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thanks to everyone for the help. I filed open the vents a tiny bit and now it works perfect!!!!! cant thank you guys enough. Man, I love this forum and the members

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On 10/10/2019 at 5:22 PM, Troutfishing303 said:

I'm glad you figured out the problem!  Does anyone else think it's weird how the hot plastisol doesn't ooze out of the vent holes?  Is the plastic cooling before it gets a chance to ooze out?

There’s a fine line between vents too small and vents too large. If they are too large, you will get plastic that flows out of them causing little nipples on your baits. Too small and the baits won’t fill. Mold also needs enough of them. So if you are opening up some vents to solve a problem, go slow. Remove a little material and try the mold. Wash, rinse, repeat until it shoots well without the flash....or nipples, if you will.

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