rico.29 Posted September 19, 2005 Report Share Posted September 19, 2005 Hello, i'm wondering if it is possible to pour cold plastic in a silicon mold and then to heat it in the microwave. as i have a mold with very thin part, it's hard to pour hot plastic in every part of the mold . so i was thinking of doing the opposite. do you think it' s possible? i can't try because i was only using my old plastic lure to pour, as i'm new to this technic. and i'm thinking about buying plastic to pour. Thank you for answering, rico. Quote Link to comment Share on other sites More sharing options...
nova Posted September 19, 2005 Report Share Posted September 19, 2005 I would think that the silicone would melt. Is your mold made with the silicone caulk? If so, silicone will stick to silicone so you could build up your mold. Quote Link to comment Share on other sites More sharing options...
rico.29 Posted September 19, 2005 Author Report Share Posted September 19, 2005 In fact it is made with silicone to pour hot lead, i think it will support heating in microwave but i would prefer to be sure. is cold plastic liquid enough to be pour without heating it? Quote Link to comment Share on other sites More sharing options...
jm Posted September 19, 2005 Report Share Posted September 19, 2005 Silicone caulk won't take the heat. Most tin cured silicones used to make molds are rated at 350* intermittent, which falls well within pouring hot melt into them at up to 400*. There are high temp platinum cured silicones, price similar to the name of the technology, that can take more heat and in fact are used for lead, zinc, and even some lower temp aluminum alloys (a380, for instance) for short runs. I doubt that your molds are made of such a material. The technique you describe is in fact one of the normal ways to make plastisol parts, and is called slush molding. The METAL mold is heated quickly either in a convection oven, or with internal heaters. It is also cooled reasonable quickly with internal cooling coils with circulating mineral oil or something like that. A silicone mold would probably have a cycle time way too long to be useful. Another thing is that old plastic lures are probably machine injected lures. The plastic is forced into the mold under quite a bit of pressure, and a thicker viscosity is actually desirable, as it limits the flash problem. Long story short, they pour thicker. I like to use such material to make master patterns because they are tough, but it is hard to work with, and I heat it up enough so the color usually changes. Patterns don't care, but lures do. The best bet for your gig would be to pour one of the higher quality plastisols available, like M-F supersoft. you can heat it up to the point that it will pour like water, and still not burn. That is probably 50* hotter than you would normally heat it, and might cause some colors to brown out or fade. If you preheat your mold to about 150*, the hot plastic will flow into smaller passages more easily. If the small part is on top, like antennae in a crawdad mold, you need to fill it with one of the glue gun rip-offs like Lurecraft sells. Surface tension in normal plastisol will probably keep it from freely flowing into such a small space. Some who are very steady can pour such things with a small pan, but I shake too much. Start by getting your free pint of supersoft from M-F manufacturing. hope this helps jm Quote Link to comment Share on other sites More sharing options...
jm Posted September 19, 2005 Report Share Posted September 19, 2005 Pardon me... Slush molding makes a shell, the excess uncured milky plastisol is poured out and the remaining is then completely cured. You are proposing cast molding. Here's a short discussion of a way it can be done. Casting / Molding Plastisols The molding process is used in a number of different situations. Floor & bar mats,decorative key chains, toys, bottle cap liners, gaskets, mud flaps, figurines, washers, oil and air filters, etc. The mold curing process may be done by oven or hot plate. Procedure 1. If the mold will be reused, the mold should be coated with a layer of mold release. We recommend our MRV 1000 IPA. Please see instructions for MRV 1000 IPA. 2. Fill the mold cavity with plastisol, add any other parts necessary. 3. The mold and plastisol is then heated by oven or hot plate. When the plastisol reaches 350? to 375? F the mold and part may be taken out of the oven. Caution must be taken with very thick parts- heating should be done gradually in an oven so that the part does not scorch. Approximately 7 minutes per 1/8 " of thickness is required @ 350? to 375? F oven temperature. Parts that are very thick should not be cured with a hot plate. 4. If the mold will be part of the final product, either a primer or a self-adhering type plastisol should be used. Note: Self-Adhering plastisol is commonly used in the process of making automotive air filters with metal end caps. Quote Link to comment Share on other sites More sharing options...
rico.29 Posted September 19, 2005 Author Report Share Posted September 19, 2005 Start by getting your free pint of supersoft from M-F manufacturing can you tell me more about this offer, does it work for europe? thanks for answering it's helpfull. as i've never use liquid plastisol (i heat only old lure to pour) i don't know how liquid it is, could it be as liquid as water? if so i think i could pour in every part of my mold without heating it. Quote Link to comment Share on other sites More sharing options...
nova Posted September 19, 2005 Report Share Posted September 19, 2005 It has the consistancy of milk. Quote Link to comment Share on other sites More sharing options...
esoxlucius Posted September 23, 2005 Report Share Posted September 23, 2005 Rico.29 I made these in silicone molds and stuff from lureparts.nl Quote Link to comment Share on other sites More sharing options...
jm Posted September 23, 2005 Report Share Posted September 23, 2005 Nice lures. Did you melt the plastic and pour them, or pour the "milk" in the molds and heat it like you first proposed? 14.95 Euros per liter puts that plastic at about $69 a gallon. How did it pour, melt, smoke, feel etc? Maybe lureparts.nl should be put in the references here for our European friends. jm Quote Link to comment Share on other sites More sharing options...
esoxlucius Posted September 24, 2005 Report Share Posted September 24, 2005 Heating liquid on a stowe and pouring into molds. It?s expensive i know, but now when i know how it works, i am trying to locate it here i EU for a better price. Or maybe i should import some myself and distribute it. :grin: Quote Link to comment Share on other sites More sharing options...
overkill Posted September 24, 2005 Report Share Posted September 24, 2005 Rico, If your molds are of the right kind of silicone, that may just work. I am sure that silicone molds can take heat, but when dealing with a microwave you are not talking about heat. You are dealing with molecular vibration, and I don't now how silicone reacts to that. If the silicone is unaffected then that would be great because only the plastisol would heat up. Only one way to find out though, but remember safety first. Quote Link to comment Share on other sites More sharing options...
rico.29 Posted September 25, 2005 Author Report Share Posted September 25, 2005 Thank you all, in fact i've tried to heat my silicone mold to micro hoven, it seems it heats easilly. i've also order plastisol from nl lure, sure it's not cheap, but it's the only seller i've found in Europe . i guess next time , i will order to US, even after paying (huge) shipping it shoud be worthy. Let me know esoxlucius if you find any dealer (by the way, great lure . I see other advantage of pouring before to heat: you use exactly the quantity of plastisol you need. i'll post again when will receive my plastisol. Eric Quote Link to comment Share on other sites More sharing options...
Delw Posted September 26, 2005 Report Share Posted September 26, 2005 Rico. Before you order any plastic try to find someone that had sucess with pouring the liquid in the mold then heating it up. A few people had tried this a year or 2 ago with our alum molds and the plastic did not cure in most of the areas. I havent heard anyone that has made this process work. they eaither burn it and dont get it cooked on the same mold. Delw Quote Link to comment Share on other sites More sharing options...
jm Posted September 26, 2005 Report Share Posted September 26, 2005 Processes that cure plastisol in an open mold usually use a convection oven. That means tightly controlled temperature, and lots of wind to keep it even. It's Way beyond the average garage operation. jm Quote Link to comment Share on other sites More sharing options...
esoxlucius Posted September 26, 2005 Report Share Posted September 26, 2005 rico.29 Makes no different i you are left with some plastisol in the pot, let it cool and store it in a zip bag, reheat it next time. Quote Link to comment Share on other sites More sharing options...
