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charkins

Don'ts for Newbies

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I notice a difference when pouring baits on a wet humid day versus on a dry warm day. So if I want to pour while it is humid or wet out I have to close the garage and turn on the exhaust fan. The plastic seems to flow better when it's dry out. :twocents: KB:yay:

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  • To emphasize what Zbass said, always pay attention to heating plastic, whether in the nuker or on the hot plate. Burning plastic fumes will burn your lungs and eyes, cause your throat to close up and swell, possibly resulting in DEATH!! You must use a vent to the outside because no one knows the carcinogens in the plastic.
Preheated plastic takes less time to liquifyOvercooking plastic results in glitter shrinkage, color bleed and pale to a gray color flakes. The more times plastic is reheated at high temps, the greater the glitter loss in size and colorThe more you heat metal molds, the hotter they are to handle. I use a heavy spring clamp, even for the first pour, and keep my hand away from the mold. My hand is steadier.By all means use more softener as a rule if adding salt. Salt firms a bait and some manufacture's plastic has more hardener in it to start with. Test the cured plastic for softness after 24 hours and then, one week after pouring to see if the final softness is maintained. A hard plastic has less action.The more translucent the color, the less glitter needed.A mix of glitter sizes gives different effects. Observe Zoom's color 54 which a mix of .015 and .040 red and black flakes. Look at other attractive baits by other large companies. No one has a patent on glitter use.

Original Fish Formula oil sold by Bass Pro is the cheapest worm oil out there and the baitfish formula smells nice, counteracting the stink of plastic.

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I am new to plastic pouring and learned this the hard way NEVER HEAT WITH A FLAME!!!! I was using a coleman stove on low everything seemed good but I made my first pour set the pot back on the stove and a flame shot up the melted plastic "string" that hung over the lip of the pot and started the whole pot on fire lucky I had a lid to snuff it out can't imagine doing this indoors with the fumes and flamibility of hot plastic.

BE SAFE!!!!!

George

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BGL. There is a temperature limit for PoP 150C (302F), beyond this temperature, the gypsum (cured mold) is converted back to plaster of Paris, resulting in a powdery mold and is spoilt. I suspect that this is what has happened in your case.

Reduce the oven temperature to its minimum, also, try wedging the door open an inch or two.

The maximum weight of water removed from the PoP is close to 35%. If you weigh the freshly poured mold on kitchen scales, multiply this figure by 0.7 (30% weight loss), this new figure is your target weight. Just take the mold out of the oven occasionally and monitor the weight. Cooking the mold beyond this figure is pointless, as you found out.

When you pour plastic, you are exceeding this temperature limit. But you have sealed the mold with elmers or some other product. This has bound the surface together and prevents the crumbling. Other than the surface, the rest of the body of the mold does not get that hot, as PoP is a very good heat insulator.

If the problem persists, consider the PoP dryer project that I posted a few months back. Not as fast as the oven, but fast enough to be convenient and perfect molds every time.

Dave

Edited by Vodkaman
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BGL. There is a temperature limit for PoP 150C (302F), beyond this temperature, the gypsum (cured mold) is converted back to plaster of Paris, resulting in a powdery mold and is spoilt. I suspect that this is what has happened in your case.

Reduce the oven temperature to its minimum, also, try wedging the door open an inch or two.

The maximum weight of water removed from the PoP is close to 35%. If you weigh the freshly poured mold on kitchen scales, multiply this figure by 0.7 (30% weight loss), this new figure is your target weight. Just take the mold out of the oven occasionally and monitor the weight. Cooking the mold beyond this figure is pointless, as you found out.

When you pour plastic, you are exceeding this temperature limit. But you have sealed the mold with elmers or some other product. This has bound the surface together and prevents the crumbling. Other than the surface, the rest of the body of the mold does not get that hot, as PoP is a very good heat insulator.

If the problem persists, consider the PoP dryer project that I posted a few months back. Not as fast as the oven, but fast enough to be convenient and perfect molds every time.

Dave

Thanks for the great information. I'm assuming that 1 hour in an oven set at 350 that has not been preheated (this is what I've been doing) never gets the mold over that magic number because they have been turning out really good. It could be relative to the thickness as well...ie, if my molds were thinner then they would reach a temp over 302. I have had good luck with my procedure but I am going to take your suggestion and lower the temp just to make sure. Who knows, maybe the ones that appear to be good won't last as long or something...Thanks, Greg

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You are probably right, the thinner mold would be the problem. It dries out quicker and then heats up faster.

The water in the mold would prevent the mold from over heating. But once the moisture is gone, it heats up. Once the majic temperature is reached, it does not mean your mold is instantly ruined, but the deterioration process begins. I could not find any information on time scales involved in the process. There is a lot of information on this reversal process on the web, which is where I got this information.

Good luck with your molds.

Dave

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I don't know about the swim bait issue, but I did learn by mistake with the POP drying on 325 for over and hour. They do crumble. You can't hardly carve any further details. I had to do any adjustments softly as possible, reseal, pour a new master bait and recreate a good working POP mold. I first thought I had mixed to much water in my POP and weakened it. Mixing a thin POP solution and pouring in from the corner makes for good results.

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I don't know about the swim bait issue, but I did learn by mistake with the POP drying on 325 for over and hour. They do crumble. You can't hardly carve any further details. I had to do any adjustments softly as possible, reseal, pour a new master bait and recreate a good working POP mold. I first thought I had mixed to much water in my POP and weakened it. Mixing a thin POP solution and pouring in from the corner makes for good results.

If you brush some POP on your masters before you embed them, you don't get air bubbles.

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since this is the good newbie thread i have to ask, What does PoP mean? and also can you use powder paints in hot plastic?

POP- plaster of paris.

I don't know what type of powder you are referring to. Other than the colorant sold for this purpose, you can use crayons, oil pastels, and coloring blocks for making candles. There might be other things that can be used i'm not aware of. You might try using the search engine with various key words. Hope this helps.

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i meant the powder paints that you use for lead jigs etc, i have been making buzzbaits and spinners for a while now and have amassed a pretty good collection. thanks for the info tho! i've been thinking of pouring plastic and have been reading this forumn pretty extensively before i give it a shot, this thread is a lifesaver tho since it dispelled some notions i had immediately! thanks again!

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If u use a microwave for heating plastic, make sure you don't use any metal flake glitter...

why would you say not to use it in a microwave? lots of us have been doing it for quite awhile and i have yet to have any problems with the glitter; maybe im just lucky IDK?

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In my opinion for you guys starting out trying to make your own molds I would highly recommend using water putty to start with. I went through a couple 25 pound bags of POP trying to get my molds to come out the way I wanted them to. After many molds that had bubbles in them no matter how thin I mixed it I just couldnt avoid bubbles in my cavities, even if it was only one I wasnt satisfied. Adding vinegar to the water putty increases your work time, which allowed me to tap the sides etc and bring the bubbles to the top, drastically reducing the amount of bubbles in the mold. After going through 50 pounds of pop and not being satisfied with the results and then trying water putty and having my first mold come out perfect I am sold on water putty for the duration! One issue I did have was I took a weekend fishing trip and left a few mold halves in the boxes I built to pour them in, when I got back there was mold on the molds! So don't leave them in the boxes or the moisture will have nowhere to go and they will grow mold!

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