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Help With Twinjector

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yeah it looks like you may have one hotter than the other, or maybe you arent getting even pressure from each.

 

my advice would be to:

Clean both injectors and o-rings.

Make sure both your plastic is around the same temperature (use an IR thermo).

Inject slow smoth and steady.

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Looking at the pictures both temps are to hot. If you want to shoot white as a belly both temps should be around 310 or lower. This way it won't have time to mix. Smooth steady pressure will get you what you are looking for. The thicker the plastic is the better the laminate will be.

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Franks right on the plastic too hot. I have just started shooting with twin injector and ran into the same problem. But i was looking at mine and the ones that i shot last were looking good then i reheated my plugs and they started mixing. Also my infra red themo is not accurate above say 250F i bought a digital candy thermo with the metal probe i checked both the infra red and digital and after 250f the infra red don't read right. the plastic is hotter than it reads.Cub48

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I thought my digital ir thermometer was wrong, until I figured this out.

I found that the plastic is cooler on the surface than in the middle, so I stir and check the temps of the middle stuff as it comes up.

Finally someone who understands you have to be stirring the plastic to take the temp with an ir temp gun. Even a digital candy thermometer need some stirring to be right. I have both and they are pretty much the same when all things are equal. Heat up plastic long Enough and you will find that temps in plastic vary so much it is unreal at times. some times I want the temp so low I have to break though a skin of cooled plastic to suck up the colors. But this gives me the most definite line in a laminate. When I reheat the colors mix a bit.
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I don't think anyone mentioned this but both colors must be of the same viscosity and type of plastisol. Put your injector and blending blockmin a toaster over to keep them both warm. I used to do that until i moved up to the Shooting Star System that eliminated the blending block and keeps the injector heated.

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Yes the temps must be within 10deg or less but if they are like 350&340 they will mix just like the photo. In this case the blending block has nothing to do with it as you can see he has both colors in the baits. Look at a mold real good and at the gate where the plastic enters it is like a nozzle. So when it is to thin it sprays in the cavity instead of flowing. Lower temp thicker plastic will flow thinner hotter plastic sprays/mixes at the gate. Look at most of the baits and you will see where the white crossed over just after the gate. Much less noticeable on colors that are transparent.

Edited by Frank
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I just wanted to let you guys know I shot some baits last night and they turned out a whole lot better. For it to work for me, I had to have both colors right at 300. I also took time to warm up everything in my oven really good. I just wish there was a set of smaller injectors available for those of us who shoot small baits. Once again, thank you all for the input. You guys sure know what you're talking about. One last question I have is where is a good place to get custom molds made? I want to get some cnc molds done for a project I've been thinking about. I googled a few places, but the only one I got word back from quoted me well over $600 for a 12 cavity 2 1/2" mold.

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I just wanted to let you guys know I shot some baits last night and they turned out a whole lot better. For it to work for me, I had to have both colors right at 300. I also took time to warm up everything in my oven really good. I just wish there was a set of smaller injectors available for those of us who shoot small baits. Once again, thank you all for the input. You guys sure know what you're talking about. One last question I have is where is a good place to get custom molds made? I want to get some cnc molds done for a project I've been thinking about. I googled a few places, but the only one I got word back from quoted me well over $600 for a 12 cavity 2 1/2" mold.

 

That sounds about right. You have to realize that when you buy a stock off the shelf mold from any one of the mold makers, you aren't directly paying for the design time, they are banking on selling a large number of that particular mold. When it comes to custom molds you now have to pay a $250 - $500 design fee as well as the mold (which you will pay a per hour rate for machine time)Custom CNC molds aren't cheap. 

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I too shoot my laminates at about 310 degrees, as Frank has stated. But I sometimes have a problem with them not adhering to each other. They sometimes can be pulled apart very easily. Do you reheat them some how for better adherence?

This is through a twinjector both colors at the same time.

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