Earthworm

[koolwater]

Have you tried using less softener,  I found that just using the HD additive in my baits made them plenty soft for my senkos and I have not had any dent issues.  I am also using the essential series plastic.  I don't know if the softener would have any thing to do with it but maybe its making them too soft,  just a suggestion.  Hope ya figure it out.

[Carl]

Kookwater I did exactly that when I received the essential plastic hoping it would eliminate it. Are you saying you don't get any dents?  How much HD are you using?

[Carl]

I just tried it again and got 5 out 8 with dents. Here are my process steps.
Warm the mold, not hot but warm.
Warm the injector and tip.
No softener added this time.
4oz plastic
2 tablespoons HD
Heated to 360.
Cooled to 325
Shot medium speed and held 20sec.
Topped off
Let sit 2 min before demold.
I get so dam frustrated every time I use these things. I need to go find the left over eggnog.

[koolwater]

I use the same as you 2 tbsp to 4 oz of plastic.  I have not ever heated my mold or injector,  I just start shooting and I have never had to hold pressure on mine either.  One day I started getting a few air pockets in mine and I switched the o-rings in my injector and that fixed that.  By the way what mold are you using?  Dont hit the eggnog yet someone on here will figure it out for you.   

[Carl]

I'm using the Do-it Senko molds. I called one of our engineers who has extensive training in Injection Molding but not the same process we use.  He said that and what I have seen here before is that the gates are closing before the rest of the material has cooled. The material is still trying to draw material from the spru but because the gate is closed, it has nowhere to pull from except itself. So it dents. Then he went into the process of cooling, and shrinking. He said there are calculations to all of this to get an accurate shot.  I asked if I'm feeding the spru with hot material won't this keep the gates open and he said not if its closing on the other side or its too small to stay open.  I told him that I don't experience this when I shoot laminates. He said that only makes his theory stronger. 

[Wallyc14]

Just my 2 ct open up the gate a little with a dremel . A couple of guys on another forum turned me on to this and it fixed mine and yes it is a senko mold a conical stone in a dremel will do it just do a little at a time also I shot the mold around 310 to 315 it likes cooler plastic ?

[Wallyc14]

I had to open up the gate a little on my senko mold so it would stop denting. i used a dremel and a conical stone to open it up just a little. I also shot the mold around315 to 320 . This fixed my problem

[Carl]

Thanks Wallyc14. I'm sure there is a print that calls for the spec of this gate. Maybe mine is on the low end of the tolerance or out of spec. If that's all it takes, then I'll open mine up tonight by a few thousands and see what that brings.

[Carl]

I'm one happy camper!!!!!.  First let me say thanks to everyone who helped me through this process. I now have a repeatable process that shoots 99%. Next, I'd like to say that we did not modify the mold any way. However I did find that "I" had some failure modes.
1. Using microwaves heats material uneven but I knew this and stirred my material.
2. My probe tip was giving false reading. I would let it sit in the cup with the tip touching the bottom of the cup. This gave me a 15 degree difference to the center of the material. So I stirred with the probe until all the material was 320.
3. Only clamped one mold at a time. I was clamping two together and this was creating uneven heat and cooling on the inside to the outside of the molds.
4. Changed from two clamps to one clamp. Because I'm shooting now at 320 at a very slow rate, I wanted to be sure all air is escaping. There was a difference.  So I clamped just past the gates.
5. Injected at a slow rate of 7-10 sec. Held pressure for 20 sec. Not overbearing pressure and without an air pressure system I can't say for sure how much I'm applying.
6. Let cool in mold for 2 min.
Being that I'm all about speed,and frankly I don't have the right equipment that allows for speed, I had to lean that slow and deliberate was faster then rework.
Again thanks to all that helped me through this. Especially some great guy named Andy. Lol. We truly have some great guys here! 

[ghostbaits]

Bet part of it was clamps were pinching off vents. I have experienced this on several molds.

Glad you got it. Bet you can demoed quicker without issue too.

Jim

[Carl]

Jim it was a variable that was incorrect amonst many others I had.

[Fontebassfishing]

When I started this hobby, I heard nothing but problems about stick baits and moved on to other baits.  Because Do-it makes really good quality molds, I was hoping that when they came out with the Senko that they got it right.  It wouldn't be ethical for me to take the molds to work and ask them to figure it out.  I didn't go to school for Injection Molding but I do know when there is a process failure. 50% scrap is a huge process failure and maybe the failure mode is me. But without a process it's just a crap shoot.

I have the 5 inch senko mold from basstackle and dont have this problem maybe every now and again but i love them senkos are my go to soft plastic bait i use so gotta make my own going to get a 6inch here soon then a 7

[sotoole16]

Hey Earthworm..  love your tubes..  on the sticks., I hand pour them in Del mart molds and have for nearly 8 years now..  I still use regular salt and at a heavy ratio..  have a very occassional failure but 95 of 100 are perfect..  super soft plastic with a little softener is all...  heavy salt