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I recently received an email from someone about strengthening gears. This person claims that by boiling the gears and then cooling them with cold water, their strength will increase. Has anyone tried this? What were your results? TJ (23 years ago, 5-Mar-02, to lugnet.technic, lugnet.robotics)
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(...) I don't think I'd want to try this. There's a reason that LEGO recommends washing the parts only in *warm* water: if you used hot water, the plastic will start to deform. Some instructions specifically state this. For example: (URL) David (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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In lugnet.technic, David Schilling writes: <snip> (...) single piece by itself will deform. If you handle it carefully (i.e. don't squeeze it hard by picking it out of the boiling water with tongs), it may not deform. But then I don't know at what (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) A quick search on Google shows that ABS (Acrylonitrile-butad...e-styrene) has a melting point of 103-128°C. Since water boils at 100°C, I don't have any doubt that you would see some deformation by that point. -- David Schilling (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) Oh people people people!!! Stop what you're doing or thinking!!! (URL) a boo halfway down the page!!! I mean this was, to date, the most traumatic event of my life!!!! (well, not really but it makes a great story when I talk to my LEGO (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) I tried cleaning Lego in boiling water once - it discolours and warps. (actually, it was Duplo - bought at a garage sale and being sterilized for the kids, but I have no reason to believe it's made from a different plastic) Matthias Jetleb (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) This sounds like the basic technique for "tempering". You've probably heard of tempered glass or tempered metal. From what I remember, this just changes the way the strength is handled in the material. A normal material bends more instead of (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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Plastic doesn't get stronger under heat-treatment. This type of heat treatment is used to control the crystallization of metals, and long-chain polymers like plastic just don't behave like that. If you need stronger gears, double them. It is the (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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| | Melting Point of ABS (Re: Strengthening Gears)
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(...) There are different grades of ABS, each having different mechanical properties. I found an extensive resource on materials at: (URL) ABS property data can be found here: (URL) picked 3 grades of ABS that seemed likely to be the type(s) that (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) Yes, this is true. (...) Now that's quite a statement! I got an email yesterday from someone saying that the axles were the weak point too. I don't know how you're using your gears, but when something breaks in my models, it's the gears! (URL) (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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| | Re: Melting Point of ABS (Re: Strengthening Gears)
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(...) They're clearly not extruded... that's the kind Plastruct(R) uses. But if they're just plain molded and not impact grade I am hoping they are from the higher end of the range. The low end mold temp (and I agree with Thomas Avery's speculations (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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| | Re: Melting Point of ABS (Re: Strengthening Gears)
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The first one you cite is probably the right one for LEGO(R) Bricks. They're molded, not extruded and I don't believe they are impact grade. Thomas Avery <thomas.avery@intec-hou.com> wrote in message news:GsI76v.GED@lugnet.com... (...) have (...) (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) I measured the temp in my attic last summer and it reached 115 F. Needless to say I don't keep much up there and definitely not my Lego collection! ROSCO had a bad "melting" experience: (URL) think this was caused by prolonged exposure to (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) IIRC, I thought it was from the back shelf of a car... cars with no windows opened can easily get to 145 or even hotter. (hence the warnings about not leaving dogs or ferrets or cats or whatever locked in cars on sunny days, it will kill them) (23 years ago, 5-Mar-02, to lugnet.technic)
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If you would just put your bricks in the kitchen oven you would make rapid progress with this question. Better yet, obtain a laboratory hot plate with fine temperature control and put a brick between two slides with a weight on top. Do this at (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) I am in total agreement with this, including the 'you' (as long as it's not 'me'... advancement of science is fine but I ain't putting my bricks in no oven thank you) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) Yes, I can see how this would help the progress of scientific knowledge, but realize that technic pieces are hard to come by in the first place these days.. you cannot walk into your local toystore and pick up a supercar... that I'll take the (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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FUT: lugnet.technic (...) There's a lot of talk and little workshop here. I know nothing about gear streangth, I have never broken a gear - unitl today. Feeling the only way to settle this is to actually test it: 1) I took a z16 gear and boiled it (...) (23 years ago, 5-Mar-02, to lugnet.technic, lugnet.general, lugnet.robotics, lugnet.build.mecha) !
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In lugnet.technic, Tobbe Arnesson writes: <snip> (...) Ha! How about that? We now have one confirmed test that gear-boiling works. Anyone care to speculate on the physics behind this? TJ p.s. Thanks Tobbe for sacrificing your gears and axles. (23 years ago, 5-Mar-02, to lugnet.technic)
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I have never broken a gear. But then, I am a mechanical engineer; I am nice to my gears. But I fry a lot of electronics! My experience is that the torsional stiffness of the axles is the limiting factor of high-torque designs. I have permanently (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) <snip> Tobbe, Was there any noticeable deformation of the boiled gear? For example, did it have any out-of-roundness (i.e. ovalization) and/or was it warped? Thanks, TJ (23 years ago, 5-Mar-02, to lugnet.technic)
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| | Re: Melting Point of ABS (Re: Strengthening Gears)
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The "service" temperature is the limit at what you should operate it at. The "mold" temperature is how LOW the mold has to be cooled to get a good shot. The "processing" temperature is the temperature the plastic has to be when it enters the mold. (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) *digging through layers of bins and instructions to find my slide calliper* Okay, measuring from one side, two gear tops resting on the caliper on each side the gear is 17.50 mm and measuring the other diagonal it's 17.45. Note that my caliper (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) Yup :) (...) The inner tension of the gear after molding got out? (...) n/p I have a few #6 axles and z16 in my overflow bin... /Tobbe (URL) (23 years ago, 5-Mar-02, to lugnet.technic)
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| | Re: Melting Point of ABS (Re: Strengthening Gears)
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(...) That reminds me of a picture I just took in December at Legoland - the Grand Central Station in Miniland had an amazing bit of damage due to sunlight! Check it out at (URL) (big file - sorry) - look in the bottom right corner of the 'window' (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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(...) So what caused the rash? Jude FUT .fun (23 years ago, 5-Mar-02, to lugnet.technic, lugnet.fun)
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| | Re: Melting Point of ABS (Re: Strengthening Gears)
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(...) Not so prolonged exposure to gas heater! (URL) (23 years ago, 5-Mar-02, to lugnet.technic)
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| | Re: Melting Point of ABS (Re: Strengthening Gears)
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(...) My guess would be 109C may be more likely - I'd be surprised if they could mold it at 109F. I'm guessing my bad experience with the heater was well over 109F (they were quite close to it), and they didn't "flow" anywhere near enough that I'd (...) (23 years ago, 5-Mar-02, to lugnet.technic)
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| | Re: Melting Point of ABS (Re: Strengthening Gears)
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Thomas: Lego uses primarily Bayer Novodur (and apparently to some extent Bayer Lustran) for its bricks. The exact composition of the Novodur is of course, like the recipie for Coke, is top secret, but it is probably closest to Bayer Novodur P2M-V A (...) (23 years ago, 6-Mar-02, to lugnet.technic)
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Wow ! Interesting results. I would have bet my firstborn that it would weaken them. Anyone else try this ? I might just to see if Tobbe's result is a fluke... (23 years ago, 6-Mar-02, to lugnet.technic)
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IIRC, ABS is a thermoset plastic. The first time you melt it it's workable at a relatively low temp and solidifies nicely, but heating it again won't melt it, only deform it and finally burn it : ( -Xanthra47 Ross Crawford <rcrawford@csi.com> wrote (...) (23 years ago, 6-Mar-02, to lugnet.technic)
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(...) That explains it. And it smells pretty bad too - that's what alerted me when I had my "accident". ROSCO (23 years ago, 6-Mar-02, to lugnet.technic)
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(...) Personally I counted on a big melt and hoped it would not ruin my kitchen hardware :) /Tobbe (URL) (23 years ago, 6-Mar-02, to lugnet.technic)
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| | Re: Melting Point of ABS (Re: Strengthening Gears)
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(...) No, it's thermoplastic. But too much heat, or even localized hot spots, can scorch it and make it unusable. (23 years ago, 6-Mar-02, to lugnet.technic)
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(...) I talked to my co-worker who's a rock climber about this interesting matter and he claims that climb ropes get better and better from stress regarding max weight/pull capabilites, however they also get crispier. Climbing ropes are generally (...) (23 years ago, 6-Mar-02, to lugnet.technic)
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(...) This is just a wild thought, but what if the boiling process doesn't alter the the strength of the material, but helps to reduce stress concentration points? If the gear deforms ever so slightly (i.e. negligible deformation- no change when (...) (23 years ago, 6-Mar-02, to lugnet.technic)
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I hahe been lurking on this conversation for a bit. Here are some random thoughts: Blocks, Gears and Axles use three different materials. By that I mean the are differnet grades of the same material or totally different materials. I lean towards (...) (23 years ago, 6-Mar-02, to lugnet.technic)
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A Mecha Shower a day keeps the autocannon bullits flying away. Legomaster (...) (23 years ago, 6-Mar-02, to lugnet.technic)
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Hello all, May be I can help a bit with this conversation, I work in plastic injection moulds, when injecting ABS it becomes stressed cause of the path it must take to fill the cavity of the mould, when ejected from the mould, the parts are supposed (...) (23 years ago, 7-Mar-02, to lugnet.technic)
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Hi Louis, (and all), I certainly don't dispute your explanation of the casting process, not at all - in fact I found it interesting to read about the cooling process. However, all the RC-10-family cars I've ever owned were made of nylon. At least (...) (23 years ago, 7-Mar-02, to lugnet.technic)
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In lugnet.technic, Kevin Maynes writes: <snip> (...) That's what this was all about: (URL) (23 years ago, 7-Mar-02, to lugnet.technic)
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(...) Been there, done that :) I think the gears are made of one kind of plastic (nylon?), axels another and bricks a third (ABS). Upon my searching through the Internet I've found a lot of pages about RC-car-wheel-boiling... /Tobbe (URL) (23 years ago, 8-Mar-02, to lugnet.technic)
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