Thread: Question

Are you referring to plastic baits? Delaminating if done with a twin injector is a sign of plastic going in the mold colder than what it needs to weld properly. Add stabilizer and jack the heat up another fifteen degrees in both colors.

And by the way, jigs are lead and hooks. Anything with plastic is a bait. Helps get rid of confusion.

Ok, plastic baits...I figured since this is DIY SOFT PLASTIC....that saying jigs would be ok...sorry about that. No not dual injectors. Single injector. Plastic is between 340 and 350.

Are you using a plate to make your halve ahead of time and storing them until its time to inject the second color? If you are do they feel oily when you put them in the mold? If oily, try washing them in alcohol and drying them well before injecting the top color. The injected plastic is hottest going to the bottom cavities first and is likely cooling enough to not be able to incorporate the oils you feel by the time the mold fills the top couple of cavities, IF you are not wiping or washing the oil off the parts made in advance. All plastics will exude an oil in storage and it can become a barrier to good welds. If you're injecting fresh plastic and this is an issue I'd try booting the heat to about 360 degrees with some stabilizer added.

I had a couple minor issues with delaminating on one bait and finally started doing the belly/bottom pours in soft plastic and then heating the medium plastic used for the injection to 360 degrees. Soft plastic will bond quicker than a medium/medium joint.

How many cavities in the mold? Are the cavities on just one side of the runner or both and if both do the top couple on each side give you problems?

40 cavity mold. They are on both sides. It start at top and as you go down the weld gets better. I have been doing this for a little over a year and made alot. And this is the first time I have seen this. I have tried injecting at a hotter temp. Clean all 3 plates to the mold...it seems to happen worse with lighter colors and glow colors....

You got some good advice from CTom

This is a new thing? What have you changed lately? Plastic brand or weight? Colorant maker?

Lighter colors and the glows can be fussier to work with simply because they tend to burn at lower temps...glow pigments are heavy and heat at different rates than the plastics do.

That's a large mold and I still feel its heat related or a problem with oily half-baits. Probably both.

I don't make the bottom half ahead of time. Everything is the same but I am in a new box of plastic..but same colorant maker and weight I have always used DO IT products. But it does seem like it would be temp. related because the bottom jigs are ok..but now that you say it i have noticed when i take them out of the mold they are feeling a little oily. I have not noticed that before. But the bottom only sets long enough to change out the plates (may 5 or 6 minutes). Is there any thing that would cause them to get oily other than setting to long? I just made some more to test them and it is the top 2 on left side in one mold and the top 4 on right side in the other mold and 1 more half way down. The other 73 of them are fine....