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I don't think sprues do make good girders, they just look like sprues to me. Girders don't look like that.

 Rolsheen wrote:
Before people start melting plastic sprues be aware that it releases cyanide gas when broken down.

How? There’s no cyanide group in the molecule? Are you thinking of carbon monoxide?

I think they might be referencing this study; about the toxicity of certain foam insulators in the event of fires. Burning polyurethane releases hydrogen cyanide gas. The amount from a few sprues would be minimal, I'd be more concerned about loose styrene molecules, but like with most of our hobby activities work in well-ventilated area or use a good filter mask.

 Horla wrote:

 Rolsheen wrote:
Before people start melting plastic sprues be aware that it releases cyanide gas when broken down.

How? There’s no cyanide group in the molecule? Are you thinking of carbon monoxide?

Nope definitely cyanide gas, personal experience with resus and ICU stay

interesting article on the difficulties of plastic recycling and possible solutions

https://www.sciencenews.org/article/chemistry-recycling-plastic-landfills-trash-materials

Whittle them into spare Necron pieces? Some modellers use them as large crystals for bases...

 Rolsheen wrote:
Before people start melting plastic sprues be aware that it releases cyanide gas when broken down.

My way is more using a solvent to turn them into goo than actually "melting" them.

I've worked with a vac-former, physically pulling semi-molten sheets of the stuff down over the bucks like mozzarella on a pizza. Leave them under the warmer too long, and it burned. Not long enough, it cooled before it hit the forms. Not anywhere near stupid enough to try melting it down with heat.

PondaNagura wrote:I think they might be referencing this study; about the toxicity of certain foam insulators in the event of fires. Burning polyurethane releases hydrogen cyanide gas. The amount from a few sprues would be minimal, I'd be more concerned about loose styrene molecules, but like with most of our hobby activities work in well-ventilated area or use a good filter mask.

Polyurethane is not the same as polystyrene though, polyurethane is based on a chain that incorporates cyanide groups into the molecule whereas polysterene is only hydrogens and carbons. Unless it reacts with airborne nitrogen when it burns?

Rolsheen wrote:

 Horla wrote:

 Rolsheen wrote:
Before people start melting plastic sprues be aware that it releases cyanide gas when broken down.

How? There’s no cyanide group in the molecule? Are you thinking of carbon monoxide?

Nope definitely cyanide gas, personal experience with resus and ICU stay

Interesting, I am honestly really surprised but I guess this is why didn't become an organic chemist!

 Kid_Kyoto wrote:
Related musing... could companies make sprues more useful?

Starting with easy thoughts, square sprue could be cut up and used for all sort of terrain and projects and would be more useful than round or trapezoid shaped.

More ambitiously could sprue be shaped to look like rocks or wreckage and be immediately useful rather than just trash?

The "Green" series of resin ork vehicles by Ramshackle games has all the gates and injection bits shaped like various pieces of armor plate/scrap metal, etc. Pretty cool terrain bits with every vehicle.

I imagine with plastic, it wouldn't be hard at all to make all round sprue look like pipes and all trapezoidal sprue have wood grain on top and bottom (not the slanted sides).

AndrewGPaul wrote: saw an article on terrain-making once where the author used an old hand-cranked mincer to chop up sprue into chunks for rubble. I've always been tempted to see if I could find one somewhere.

I remember that same article. I think it might have actually been a GW White dwarf idea originally in the early 00's? Could also have been Terragenesis. My assumption for great old terrain ideas is usually that it came from Necromundicon (now IronHands.com) but I don't think this one did.

chromedog wrote:You need one of the old metal cast grinders with the METAL auger screw. With the big screw foot to attach them to the bench.

The problem is, they tend to be cast aluminium and have succumbed to corrosion by now.

I don't know about the UK, but metal hand cranked meat grinders are actually fairly common at US antique stores for less than $20. I picked up a vintage one in-the box with multiple augers that I think is cast iron for $10 at a resale shop a long while back. I think I made one batch of sprue rubble with it. Not sure why I haven't since.

 Horla wrote:

PondaNagura wrote:I think they might be referencing this study; about the toxicity of certain foam insulators in the event of fires. Burning polyurethane releases hydrogen cyanide gas. The amount from a few sprues would be minimal, I'd be more concerned about loose styrene molecules, but like with most of our hobby activities work in well-ventilated area or use a good filter mask.

Polyurethane is not the same as polystyrene though, polyurethane is based on a chain that incorporates cyanide groups into the molecule whereas polysterene is only hydrogens and carbons. Unless it reacts with airborne nitrogen when it burns?

Rolsheen wrote:

 Horla wrote:

 Rolsheen wrote:
Before people start melting plastic sprues be aware that it releases cyanide gas when broken down.

How? There’s no cyanide group in the molecule? Are you thinking of carbon monoxide?

Nope definitely cyanide gas, personal experience with resus and ICU stay

Interesting, I am honestly really surprised but I guess this is why didn't become an organic chemist!

I don't really get how you get cyanide from styrene either, but I was taught in my chemistry classes to never melt down random plastics because even if you know what type of plastic the bulk of the material is made from, you don't know what blends and additives have been mixed into it.

But in terms of recycling plastic frames into other useful items such as terrain, unfortunately GW sprues are a very recognisable shape and it takes work to turn it into something that doesn't look like a sprue.

Model planes and cars I've bought generally use circular cross section frames, and it's a lot easier to come up with ideas that aren't too labour intensive for turning them into terrain or something else.

 Horla wrote:

PondaNagura wrote:I think they might be referencing this study; about the toxicity of certain foam insulators in the event of fires. Burning polyurethane releases hydrogen cyanide gas. The amount from a few sprues would be minimal, I'd be more concerned about loose styrene molecules, but like with most of our hobby activities work in well-ventilated area or use a good filter mask.

Polyurethane is not the same as polystyrene though, polyurethane is based on a chain that incorporates cyanide groups into the molecule whereas polysterene is only hydrogens and carbons. Unless it reacts with airborne nitrogen when it burns?

I'm aware they're not the same. I honestly can't remember exactly why but I think my thought process mentioning it was because sometime people confuse the plastics types, and I missed including PS for clarification in the sentence about sprues to differentiate them. Kind of ironic.
For some reason that study uses the abbreviation PS in the results, but the type they used was expanded polystyrene (styrofoams).
It tested the lowest on released HCN, but it still released some. Maybe from the chemical reactants they use to "inflate" the PS, I don't know.
As for why sprues would release it, pigments or stabilizers maybe? it's been a decade since I had to remember this stuff.

I forgot to mention about a technique from an old white dwarf or maybe even here, using a hobby knife to par a length of sprue so it coils for making plants. But could also be used for wrought iron type terrain.
Found it: https://www.terrainmonster.com/terrain-building/scratch-building/carving-sprue-plants

 Eilif wrote:


I don't know about the UK, but metal hand cranked meat grinders are actually fairly common at US antique stores for less than $20. I picked up a vintage one in-the box with multiple augers that I think is cast iron for $10 at a resale shop a long while back. I think I made one batch of sprue rubble with it. Not sure why I haven't since.

I'm not in the UK - but it's been a few years since I've seen one of those old hand-crank mincers. We have 1/13th of the US population spread over a slightly smaller landmass, though. Last one I saw at a boot sale was about 2007.
Even online trading sites have them as scarce.
Partly because as mincers go, they are pretty hardcore and great for doing certain meat cuts - and they make short work of connective tissues, too. Pulverising all of it.

I checked my local site and they handle plastic #1-5 and #7. Sadly it looks like GW sprues are #6.

I use a lot of sprues as scaffolding pieces for scratchbuilds and conversions, in places where the recognizeable shape of the sprue isn't immediately recognizeable. I also make use of the uniform thickness of most sprues as spacers when working with sheet styrene.