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Has anybody tried melting sprue plastic and remolding it in a simple mould? Would it even work? I have a lotta sprues and melting and molding sounds like a good idea. I know you can bend the plastic using a hair dryer so you wouldn't need that much heat, maybe you could even use an oven!

No. Do not do this. Ever. Seriously.

If you want to cast stuff, either go all the way and get two-part resin or search the forums for instructions on making press-molds using "green stuff" putty.

People have done press molds with the extra sprues, but it generally is a waste of time and can be very unsafe if done incorrectly.

Listen to Breotan's advice.

Yeah, I reckon the plastic needs to be direct inject moulded, its only good for moulding once, you can melt it if you want, but it won't get you as good results as the first time. Not to mention the fumes and junk, its not a good idea.

Yeah, don't try it unless you have access to actual injection molding facilities and fumigation hoods. Better to go with a 2 part resin for that sort of stuff.

Sprue can still be useful in modelling, though, for carving little detail bits from, or making terrain, walls, shields, etc. Might want to check out the "Tired of throwing away old sprue?" thread here.

Sprue like most plastic products are not recyclable by the end user. They produce toxic fumes. If you want to cast try two part polyurethane resins. Always superior to press molding but never replaces it.

If you warm it up with a lighter but don't set it on fire then it can be pretty handy for making stuff.

AustonT wrote:Sprue like most plastic products are not recyclable by the end user. They produce toxic fumes. If you want to cast try two part polyurethane resins. Always superior to press molding but never replaces it.

Someone one here was saying that GW melts down pellets and excess plastic to mold their minis, I am almost 100% positive that that was incorrect, but he wouldn't hear any of it.

If you wanted to use this with instant-mold. I would suggest sticking with the original recommended greenstuff, but you may be able to save some greenstuff when instant-molding large parts by bulking the middle out with chunks of sprue (like if you were casting a large wheel, you could get a lump of gs, and fold it around some sprue hunks, then press it into the mold)

Not sure how it would work out though, although I will also support the 'dont melt it' school of thought...

nectarprime wrote:

AustonT wrote:Sprue like most plastic products are not recyclable by the end user. They produce toxic fumes. If you want to cast try two part polyurethane resins. Always superior to press molding but never replaces it.

Someone one here was saying that GW melts down pellets and excess plastic to mold their minis, I am almost 100% positive that that was incorrect, but he wouldn't hear any of it.

That is absolutely what GW does. Well not pellets per se. Large scale injection molding generally uses granules. If GW does actually recycle (I don't know if they do) they would grind the old sprue into granules as well. If they use thermoset plastic they probably don't recycle it at all. I don't know if you were arguing against the recycling or the process but it's likely you were both about 50% right .

nectarprime wrote:

AustonT wrote:Sprue like most plastic products are not recyclable by the end user. They produce toxic fumes. If you want to cast try two part polyurethane resins. Always superior to press molding but never replaces it.

Someone one here was saying that GW melts down pellets and excess plastic to mold their minis, I am almost 100% positive that that was incorrect, but he wouldn't hear any of it.

All plastics factories reuse excess plastic, depending on the material and product. I work at an injection molding factory. We routinely grind up faulty parts and sprues/runners and mix it with new material to be reused. It should be noted that it isnt used straight, the ground up plastic is mixed with new material, usually 5%-25% old in with the new. Plastic weakens and loses its properties every time its melted, so there is a limit to how many times it can be done before its just junk.

Also, as someone pointed out its not poured like resin or metal, its injected...at pressures from 1000 to over 20,000 PSI.

Melting plastic also releases toxic fumes.

Bottom line...either use the sprues for conversions or throw them out.

Mad4Minis wrote:

nectarprime wrote:

AustonT wrote:Sprue like most plastic products are not recyclable by the end user. They produce toxic fumes. If you want to cast try two part polyurethane resins. Always superior to press molding but never replaces it.

Someone one here was saying that GW melts down pellets and excess plastic to mold their minis, I am almost 100% positive that that was incorrect, but he wouldn't hear any of it.

All plastics factories reuse excess plastic, depending on the material and product. I work at an injection molding factory. We routinely grind up faulty parts and sprues/runners and mix it with new material to be reused. It should be noted that it isnt used straight, the ground up plastic is mixed with new material, usually 5%-25% old in with the new. Plastic weakens and loses its properties every time its melted, so there is a limit to how many times it can be done before its just junk.

Also, as someone pointed out its not poured like resin or metal, its injected...at pressures from 1000 to over 20,000 PSI.

Melting plastic also releases toxic fumes.

Bottom line...either use the sprues for conversions or throw them out.

I also work at a factory that does injection plastic molding, I guess our materials/procedures are not the norm. We use 2 part liquid plastics that turns solid (polyurethane I believe), and we don't recycle any of the excess hard plastic back into the process.

I'm curious though, why doesn't GW have a "sprue recycling" program? We know they're money hungry, I would think they would jump at a chance to save even a little bit.

They would probably be inundated with more than they could ever reuse within a month...as mad4minis said, you can only use so much recycled...

Unless they have a manufacturing centre in your country, it's also not cost effective for them (the shipping from Oz to the US or UK alone makes it not worth it).

The plastics factory a mate worked at was like the one Mad4Minis worked at (grind up and re-use at around 10%).

Lego reuses their offcuts (but it's not polystyrene) for further batches.

This thread pops up now and again

You are better off taking your left over sprue and using it as rough wood paneling, bricks, or rubble.

wood panneling/logs etc: clean the sprue up with a knife and file so you have a roughly square log. Next, take a saw and run it down the length of the 'log' to texture it. The result when painted should look like low-quality/rough-cut timber. Be sure to intersperse panels of differing widths, and at different indentations (when gluing one piece directly to another) to give it a more realistic rush-job/lowtech look.

Bricks: clean up with a file, and then cut into equal-length sections. Time and glue consuming, but a great way of recycling your stuff to add texture or rubble.

Objective markers: The trapezoidal shape lends itself well for making.... BARS OF GOLD!!!!!! Clearly, nonsensical as an objective marker for certain races, but, hey, come on, whats more fun than a mad rush for heaping piles of gold ingots?

Lastly: framing. If you are going to build custom-vehicles, or buildings that you will cover with other plastic pieces, or you need a sturdy frame to take weight so you can use a thin material floor or whatever, then using your sprue as framing material is another way to avoid waste.

Bear in mind, when assembling, the trapezoidal shape of the sprue lends itself well to construction. depending on how you assemble it you can incorporate curves and straight sections at will.

poda_t wrote:This thread pops up now and again

You are better off taking your left over sprue and using it as rough wood paneling, bricks, or rubble.

wood panneling/logs etc: clean the sprue up with a knife and file so you have a roughly square log. Next, take a saw and run it down the length of the 'log' to texture it. The result when painted should look like low-quality/rough-cut timber. Be sure to intersperse panels of differing widths, and at different indentations (when gluing one piece directly to another) to give it a more realistic rush-job/lowtech look.

Bricks: clean up with a file, and then cut into equal-length sections. Time and glue consuming, but a great way of recycling your stuff to add texture or rubble.

Objective markers: The trapezoidal shape lends itself well for making.... BARS OF GOLD!!!!!! Clearly, nonsensical as an objective marker for certain races, but, hey, come on, whats more fun than a mad rush for heaping piles of gold ingots?

Lastly: framing. If you are going to build custom-vehicles, or buildings that you will cover with other plastic pieces, or you need a sturdy frame to take weight so you can use a thin material floor or whatever, then using your sprue as framing material is another way to avoid waste.

Bear in mind, when assembling, the trapezoidal shape of the sprue lends itself well to construction. depending on how you assemble it you can incorporate curves and straight sections at will.

+1. I love me some gold ingots...

Anyway, yeah. Trying to remold sprue isn't really something that people can do without industrial tools, ya know? I rule it up to KISS: Keep It Simple, Stupid. GS the mold stuff, use the sprue for remnants and other crap like that.