Reheating plastic

[MonteSS]

I use a 4 Cavity 2-piece aluminum 5" Stick mold and hand pour it.

I usually mix 4 oz of CCCC plastic. 1 TBSP salt plus dye and glitter. Initial heat color is good. Each reheat after that the color changes and darkens. Will heat stabilizer totally prevent this or just help reduce it. The way I am doing it is impossible for me to get consistant colors. I tried adding about 1 oz of fresh plastic between reheats but didnt seem to help. These baits are for me and it's not that big of a deal, but I would like to get that nice color I want for more than four baits.

Thanks....Bill

[pjmcla]

I am relatively new to injecting. I have only used about 2 gallons of plastic so far; but maybe I can help.
I also use CCM Plastic.  Do you use a thermometer and check your temperature closely?  High temps will degrade color; esp without heat stabilizer.  I always add 2 drops per 2 oz of heat stabilizer.
I do not use salt. The only color I have found, so far, that degrades is the Flourescent Yellow Chartreuse.  I have reheated some plastic ten times.  I watch my temps close and do not go above 360. ( well once in a great while I go high ). I have no noticeable color changes.  Try some without salt.  See if that helps.  At least you will know what the "problem" is if "no salt" helps.
Are you trying to alter the plastic characteristics with the salt; or just add the salt as a "flavoring"?
  

[superharmonix]

I use a 4 Cavity 2-piece aluminum 5" Stick mold and hand pour it.

I usually mix 4 oz of CCCC plastic. 1 TBSP salt plus dye and glitter. Initial heat color is good. Each reheat after that the color changes and darkens. Will heat stabilizer totally prevent this or just help reduce it. The way I am doing it is impossible for me to get consistant colors. I tried adding about 1 oz of fresh plastic between reheats but didnt seem to help. These baits are for me and it's not that big of a deal, but I would like to get that nice color I want for more than four baits.

Thanks....Bill

Bill,  if you have a thermometer, I echo pjmcla's comments.  If you do not, there's a handheld laser thermometer at Harbor Freight for around $25.00.  Great investment in this game.
I have run into this issue, part of the nature of plastic, and the best thing to do if you are having a hard time keeping the temp consistent, is if you have a power setting on your microwave, try turning it down to 70% or 80%...Then heat for the same amounts of time as you usually do.  This should help. 

[Jason]

Are you cooking your colorant with your plastic on the initial heating or adding it after the plastic is hot?

Another thing to look out for regarding temps is your glitter.  Take clear plastic with just about any color glitter in it and heat it up to 375, 380, or so.  The first time depending on the glitter you may be okay, with each reheat more color will transfer from the glitter to the plastic.  Not an ideal thing, but it is pretty manageable with your temps.

[MonteSS]

Thanks for replys.

I heat the virgin plastic till it turns clear. Add color, salt, and glitter and stir. Nuke anther 30 secs (its an old low power microwave). Heat to around 350* using an IR themometer.

First time it's say a nice transparent purple. First reheat it turns more burgundy and more opaque. Then goes more brown from there on.

...Bill

[superharmonix]

One thing you might try is stirring your color in while the plastic is cold, then heat.  See what happens....
What kind of plastic are you using and is it mixed up? 

[pjmcla]

Another Light bulb.  I am slow of mind as well as of foot.  It could be the glitter reacting.  With the  Flourescent Yellow Chartreuse; I also had a glitter "reaction". Silver glitter will turn it a nice mint green; and get more minty each reheat.  Don't know about purple and glitter.  

[ghostbaits]

It is the glitter for sure. Purple is notorious for this and has been this way for years actually. I have used metallic (instead of poly) due to this however is is tough to find the metallic now.

Your green pumpkin will do the same thing. Nice greenish color on the first run and progressively more brown as you re-heat.

Staying around 325 helps but does not eliminate this issue. Some companies don't even offer medium purple flake due to the issue. All the others must get theirs from the same manufacturer as they all seem to bleed.

Jim

[Jason]

Thanks for replys.

I heat the virgin plastic till it turns clear. Add color, salt, and glitter and stir. Nuke anther 30 secs (its an old low power microwave). Heat to around 350* using an IR themometer.

First time it's say a nice transparent purple. First reheat it turns more burgundy and more opaque. Then goes more brown from there on.

...Bill

Bill,

Just just to summarize the feedback, it is probably the glitter.  If you know how much colorant you are going to add, add it to the plastic when it's cold.  Colorant is plasticizer and pigment (it is ideal for it to cook also).  Save your glitter until you are ready to inject, keep your temps low on reheats, work in small (as close to exact) batches as possible to minimize reheats.

Jason

[bribass]

going off the idea being brought up in this thread... Are you suggesting not to reheat the sprues or cut them up and remelt them?

Ive dont this with other plastic and most colors are not a problem, but was interested on how the CCplastic holds up to this process?

Anyone have experience with this?

[MonteSS]

Thanks again.

It is not just purple dye color or purple glitter. Happens with other colors and even if I dont use glitter. I havn;t tried without the salt.

I actually checked and I heat the platic to about 375* which is the only way I can get it thin enough to hand pour a single four cavity mold.

Maybe its time for an injector so I dont have to heat so high.

....Bill

[ghostbaits]

375 is high to me and that would seem to be your problem. You may need more heat stabilizer if you are going that high as that temp probably cooks it all out quick.

I defer to Jason on this one though as I don't take my plastic up that high.

The color changes could be from the plastic breaking down and yellowing at that temp.

Jim

[andrewlamberson]

What does heat stabilizer do (from a chemical perspective)?

How much should you add to 1 cup of plastic?

I normally add 4 drops...on the 3rd re-heat of virgin. 3 drops on any re-melt of a bait.

Does heat stabilizer make the plastic "softer" or "harder"?

I like to use a digital cooking thermometer (make sure it's good to over 400 degrees..)

Like this one:  http://www.target.com/p/Taylor-Weekend-Warrior-Antimicrobial-Digital-Instant-Read-Thermometer-Stainless-Steel/-/A-10376027

Also, remember that anything that is microwaved may continue to "cook" for a period of time (the molecules stay excited and vibrating)!!! Don't think so? Heat you plastic to 350 and stir with the digital food thermometer (the long stainless steel probe is perfect for that) and watch how high you temperature goes!!! I'd bet if you are heating to 375...the plastic is going over 400 degrees within the first 30 seconds out of the microwave.

From: http://www.fsis.usda.gov/factsheets/microwave_ovens_and_food_safety/index.asp#14

Microwaves cause water, fat, and sugar molecules to vibrate 2.5 million times per second, producing heat. After the oven is off or food is removed from the oven, the molecules continue to generate heat as they come to a standstill. This additional cooking after microwaving stops is called "carryover cooking time," "resting time," or "standing time." It occurs for a longer time in dense foods such as a whole turkey or beef roast than in less-dense foods like breads, small vegetables and fruits. During this time, the temperature of a food can increase several degrees. For that reason, directions may advise to let a food "rest" for a few minutes after turning off the oven or removing food from the oven.

I set my microwave down to medium at the end of the heating cycle...or I often get scorching. This is probably more important if you have a high wattage microwave ...which will cook faster than a lower wattage unit.
(read the "Time-to-Boil Test" in the above mentioned article).

[bribass]

ya now looking at the temps... my guess would be your a little too hot! 

but im sure jason will chime in on his thoughts about going that high in temp 

[Jason]

When you cook your plastic it is actually changing what it is at a molecular level.  Chlorides (the "C" in PVC) want to attach themselves to something.  In the absence of a heat stabilizer, it will attach itself to the vinyl.  This is what causes yellowing.  With heat stabilizer present it attaches itself to it - thus preventing yellowing.  Each molecule of heat stabilizer can only be attached to one time.  That is why at some point you may need to add more.

With that said, if you are using Crystal Clear there is no way you need to add stabilizer on the first or second heating - even if you are taking it up to 420 degrees.  I test this on a regular basis (every batch).  It is not until the third heating at this extreme temp is additional stabilizer needed.  Under less intense circumstances (not exceeding 360 / 370) you can easily get 3 - 4 heatings out of it (I will normally add 4 drops of stabilizer to a half cup on the 4th heating if I'm abusing it).  Disclaimers - this is with my microwave, using all CCM products (they are designed to work together).  There are literally thousands of different stabilizers to choose from, we use a blend that we have found to be optimum for what we are doing.

Here is an easy test, go through your process with clear plastic.  Make sure and roll the box over a couple times first.  See if your plastic changes.  Then try it with colorant (add it before heating).  Then try it with glitter.  Then try it all together.  If you keep your temps reasonable you will be able to reuse all the plastic so there isn't any waste.  This will give you a good idea what each component is doing so you can identify where the problem is.

A final note on stabilizer...  Adding to much when it's not needed will produce additional smoke and smell.  I haven't seen it make a bait softer or harder (I'm sure if you used it like softener it would do something???), but I have seen where to much will make a bait more brittle.

Hopefully something in here is helpful.

Jason