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Candid discussion about Tamiya #2 (materials)

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I debated putting this in with the first discussion but didn't want to overload the topic. Anyway, back in the day, pretty much all kits from all manufacturers were considered RC "models". When discussing RC at a racetrack however, Tamiya vehicles were often referred to as toys. At the time this perplexed me as I felt Tamiyas were of superior quality. They certainly assembled beautifully. As time went by, I began to see the issues they had with design that kept them out of the winner's circle but it went deeper than that. The problems started with what Tamiyas were primarily made from : ABS plastic.

Back in the day, a lot of manufacturers used plenty of ABS so it wasn't an surprise. However, there was a reason Associated and competition Kyosho cars were more up to the task. Today, there are much better plastics available. While Tamiya did eventually start working other plastic types into there vehicles, should they still be using ABS today as much as they do (especially depending on application)? I've spoken with several people, some of whom are engineers in plastic parts production and the general consensus is ABS is cheap and not quite the best material. Now ABS has its upsides. Tamiya has certainly mastered molding it into complex shapes (though the tolerances are a bit big). Its easy on molds as glass fibers can erode passageways over time. I still think Tamiya is fine to use ABS in beginner type cars although admittedly wouldn't the much tougher plastics Traxxas uses be much better? Where it particularly irks me is in cars that could see track duty.

Nothing is as hard on a vehicle as racing, but I've had plenty of Tamiya plastic fail from normal use. Below is picture of a front gearbox housing from a Dirt Thrasher

48684729622_9bedaf4652.jpg20190904_191708 by Scott Weiland, on Flickr

As you can see, the attachment points for the lower cover are split and cracked. The was a new buggy I assembled back in the day for my girlfriend at the time. It saw about 6 months of use on a ball diamond, was never jumped, nor crashed. The same gearbox is found in the Top Force and Evo. How would one of these hold up in the rigors of competition? Now, I begin to see the comment of Tamiyas being toys at the track making sense. The review on Oople shows what can happen to the mainly ABS DF03 in competition. Tamiya can do better. They certainly did with the DB01. Even the earlier Egress has a multitude of different plastics making it "better" in this area than the Top Force.

48684557451_8eb9b24bbe.jpg20190904_191347 by Scott Weiland, on Flickr

Here we have a Thundershot rerelease. It was run about 5 times without incident before being put on a shelf. The upper arm mount split from sitting on a shelf. Now, there are design reasons for these failures and they can be discussed at length if so desired, but the material is commonly the culprit.

So, if ABS was fine in the old days, do you feel Tamiya should modernize their material usage for modern times? I admit there are rumors that the plastic Tamiya used during the era around the Dirt Thrasher may not be good. From my own collecting over the years, Madcaps, Astutes, and King Cabs seem to be more afflicted from cracks and breakages vs say, a Boomerang-era buggy. Any thoughts or insights appreciated.

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People's opinions probably wouldn't change about Tamiya no matter what material they used! 

Ultimately if Tamiya want to be accepted more as mainstream and not just cater (mostly) for their home market then I'm sure they are more than capable of using superior materials across the board, I'm guessing!

It is what it is, now I've accepted it more than I did a few years ago, it doesn't bother me, maybe 3d printing and copying parts in stronger materials will also fill that gap in the future?

Regarding the tshot, only my ragged runner with 50+ hours has splits like this (it doesn't affect running though), others are ok

Maybe it's the 'lottery' of production, how the kits were stored etc etc?

I know the screw pins won't help, especially if tightened right up, never tried the "soldering iron to heat it up trick" before screwing it in.

It's good that quite a number of us are so passionate about Tamiya we wish they did this and that, it's amazing their products are in production for as long as they are, other manufacturers comparitively seem to drop older models quite quickly!?

I bet the discussion about the new cc-02 will be just as entertaining!

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I honestly think @Juggular nailed this elsewhere 

Tamiya hasn’t drawn blood in pro racing for years - and instead offers deliberately fragile kits that appeal to model makers / nostalgic engineers ... like me 🙄

ABS is cheap, simple and brittle once overloaded ... offering a gold mine of hop ups / spares Tamiya can tap sporadically - then wait until aftermarket  inflation mutes any kind of pricing pressure + they respin a batch for 30% more. 

I once held hope that commoditisation  of space / aviation 3D printing methods and materials would usher in a new dawn of race bred Tamiya ... where minimal up front costs let them blitz Associated with the design genius they’ve always been blessed with.

But these days I think they’re sadly just lazy and greedy 🙁

The only upside is it’s a strategy that pretty much guarantees they’re financially secure - so the next generation should (a) be there and (b) might hopefully get better kits 🤞

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15 minutes ago, SuperChamp82 said:

But these days I think they’re sadly just lazy and greedy 🙁

exacto mondo. we're not kids anymore. let's not fool ourselves into thinking mr.tamiya is like santa making toys purely for our enjoyment. just like any manufacturer, built-in obsolescence, and profit motive come into play. its why the high-torque servo saver will never be standard issue or your plastic bushing collection will keep on growing. they can build with better materials or use better designs - but its gonna cost.

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50 minutes ago, Saito2 said:

I debated putting this in with the first discussion but didn't want to overload the topic. Anyway, back in the day, pretty much all kits from all manufacturers were considered RC "models". When discussing RC at a racetrack however, Tamiya vehicles were often referred to as toys. At the time this perplexed me as I felt Tamiyas were of superior quality. They certainly assembled beautifully. As time went by, I began to see the issues they had with design that kept them out of the winner's circle but it went deeper than that. The problems started with what Tamiyas were primarily made from : ABS plastic.

Back in the day, a lot of manufacturers used plenty of ABS so it wasn't an surprise. However, there was a reason Associated and competition Kyosho cars were more up to the task. Today, there are much better plastics available. While Tamiya did eventually start working other plastic types into there vehicles, should they still be using ABS today as much as they do (especially depending on application)? I've spoken with several people, some of whom are engineers in plastic parts production and the general consensus is ABS is cheap and not quite the best material. Now ABS has its upsides. Tamiya has certainly mastered molding it into complex shapes (though the tolerances are a bit big). Its easy on molds as glass fibers can erode passageways over time. I still think Tamiya is fine to use ABS in beginner type cars although admittedly wouldn't the much tougher plastics Traxxas uses be much better? Where it particularly irks me is in cars that could see track duty.

Nothing is as hard on a vehicle as racing, but I've had plenty of Tamiya plastic fail from normal use. Below is picture of a front gearbox housing from a Dirt Thrasher

48684729622_9bedaf4652.jpg20190904_191708 by Scott Weiland, on Flickr

As you can see, the attachment points for the lower cover are split and cracked. The was a new buggy I assembled back in the day for my girlfriend at the time. It saw about 6 months of use on a ball diamond, was never jumped, nor crashed. The same gearbox is found in the Top Force and Evo. How would one of these hold up in the rigors of competition? Now, I begin to see the comment of Tamiyas being toys at the track making sense. The review on Oople shows what can happen to the mainly ABS DF03 in competition. Tamiya can do better. They certainly did with the DB01. Even the earlier Egress has a multitude of different plastics making it "better" in this area than the Top Force.

48684557451_8eb9b24bbe.jpg20190904_191347 by Scott Weiland, on Flickr

Here we have a Thundershot rerelease. It was run about 5 times without incident before being put on a shelf. The upper arm mount split from sitting on a shelf. Now, there are design reasons for these failures and they can be discussed at length if so desired, but the material is commonly the culprit.

So, if ABS was fine in the old days, do you feel Tamiya should modernize their material usage for modern times? I admit there are rumors that the plastic Tamiya used during the era around the Dirt Thrasher may not be good. From my own collecting over the years, Madcaps, Astutes, and King Cabs seem to be more afflicted from cracks and breakages vs say, a Boomerang-era buggy. Any thoughts or insights appreciated.

You hit the nail right on the head in the first paragraph... they are refered to as toys. My earliest memories of tamiya were seeing them built in shop windows looking every bit the detailed model, i could never have imagined crashing them into kerbs and things, they were just to good and fragile. Remember the poster for Tamiya stating that 'Toys they are not'? They became more toy like in the 80s when kits such as the hornet were released.

I dont think the ABS was ever up to being thrashed around like the earlier metal parts, but Tamiya had to move with the market and produce the kind of models that people wanted to thrash and could afford. But then, isn't that the way with all manufacturing?

J

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18 minutes ago, MockTurtle said:

let's not fool ourselves into thinking mr.tamiya is like santa making toys purely for our enjoyment.

While I totally agree with this statement, I will say as Mr. Tamiya and Fumito Taki (the fellow behind the birth of Tamiya RC and its driving force) have aged (and no doubt stepped back a bit from the forefront), Tamiya just hasn't been the same. 

Associated built racing vehicles, so much of what they made is up to snuff. I wish Tamiya took the road Kyosho did. The fun vehicles remained ABS while the more serious ones incorporated aluminum and glass fiber reinforced parts.

I have a feeling some of the reason the Top Force didn't quite have the variety of plastics that the Egress did was down to its intended versatility. It had to be a comp buggy, a beginner buggy and a touring car all in one package. The Egress was just built for performance.  I have no qualms with Tamiyas fun vehicles being plastic fantastic, nor the Hot Shot series as ABS was really prevalent as we moved out of the "metal era" but by the Thundershot, I think they should have begun to get with the program. They promoted the T-Shot as a comp buggy and even got some racers to drive them. Despite all its faults, at least they tried different materials with the Avante (granted, some unsuitable materials, but different).

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9 minutes ago, Saito2 said:

While I totally agree with this statement, I will say as Mr. Tamiya and Fumito Taki (the fellow behind the birth of Tamiya RC and its driving force) have aged and no doubt stepped back a bit from the forefront, Tamiya just hasn't been the same. 

hehe, when i said "mr.tamiya" i was referring to the company as a whole. not sure about the company changing though - maybe its just because we've grown up?

i mean, they still come up with quirky products, ie. comical, kumamon etc. and there's the mini 4wd crowd. the tamiya plamo side is also without its gripes  (then again rivet counters will always have something to say), but they do come up with masterpieces occasionally (the recent 1/32 aircraft series). what is impressive is that they have stuck to their respective market segments without tarnishing their reputation for quality.

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Yeah, that's one area where Tamiya could improve - they rely too much on ABS for structural parts.

What's funny is that when I got my first RC car, I really wanted a Kyosho Pegasus, not a Grasshopper. The local hobby shop owner (as well as my dad) steered me away from it, because they both thought the soft plastic living-hinge suspension arms would not hold up. They convinced me to get a Grasshopper instead, because of the "better" materials.

Fast-forward 30 years, and I've restored half a dozen Pegasus-chassis cars. I've seen all kinds of broken parts on them, except... the suspension arms.

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1 hour ago, markbt73 said:

soft plastic living-hinge suspension arms

Wow, I never knew that (or saw that on an RC car in general). You learn something new everyday. I just checked out the manual. Things sure were more creative back in the day.

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Tamiya uses carbon reinforced plastic for many of the on road cars for more than a decade now. Not sure if they're also used in the buggies though. But they should have done this longer time ago. Associated, Traxxas, HPI and a couple more brands have been using them. 

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First, I must point out that I know very little about plastics and molding and I'm very much aware of that myself, so I'm not at all trying to play an expert here. However, the last 7 years, I've worked for an automotive supplier who primarily manufactures plastic parts. So, with my interest in RC- and static plastic models, I've taken the opportunity to speak with some of the specialists at work. 

Choice of type of plastic to mold parts in is not just about the cost of the plastic itself. Tough and reinforced plastics cause a lot more wear on the molds, both because they have to be injected with higher pressure and because of their abrasive effect. That isn't so relevant for (relatively) small volume manufacturers like Associated and Schumacher, but it certainly is for a high volume manufacturer like Tamiya. As pointed out here already, Tamiya use high strength plastics in their TRF-models, but not just because they are more expensive and sold to more demading customers, but also because mold wear isn't so relevant for these low volume models.  For high volume models however, mold wear is of course an issue, so if Tamiya had used for instance fibre reinforced nylon throughout in the DT-02, DT-03, TT-02 and similar high volume chassises, the cost of repairing, maintaining and replacing molds would have been significantly higher and eventually handed down to the customers.

Also, takt time is a factor.  Generally, high grade plastics demand a longer takt time. The longer it takes to mold (heat, inject, cool, eject) a part/sprue, the longer the machine is occupied for a production run and the higher the labour cost, energy cost etc. Furthermore, shrinkage, warpage and general tolerances are critical issues that Tamiya need to have under control and some plastic materials are much more demanding than others on these issues, resulting in higher cost for monitoring the processes and for corrections whenever the tolerances start to drift.

There surely are many other factors too, but just the above is in my humble opinion enough to feel confident that Tamiya are very much aware of their choices and that they leave very little to chance.  That said, I don't excuse Tamiya for poor designs though. Meanwhile, Tamiya have decades of experience making RC-models of relatively fragile plastics, so they should know pretty well how to design parts to make them suitable for their specific tasks, like for instance required stiffness and tight tolerances for a gearbox housing, balance of stiffness and toughness for suspension arms, gloss, homogeneous colours and crispness of decorative parts and not the least the required wall thicknesses and dimensions.  And I dare say that the design flaws are not so common anymore, and Tamiya know pretty well how to cleverly design (plastic) parts to compensate for their use of "brittle"  or soft plastics.

Also, outside Japan many of us may feel that Tamiya models are (sometimes) not so good value for money, but in Japan, the prices for Tamiya models and spare parts are pretty low and parts availability is probably not even remotely as good in any other part of the world. So Japanese customers possibly think they get good value for money and when a plastic part breaks or is worn out, replacement is cheap and easy to get. And after all, Japan is still Tamiya's most important market by far. 

And think of it, has there been any new Tamiya chassis the last 20 years with as severe design flaws (causing breakage of plastic parts) as those commonly found back in the eighties and into the nineties? I can’t think of any.  The Juggernaut was an extremely poor effort for so many reasons, some of which were also related to poorly designed plastic parts, and some later chassis designs have issues, but if I’m not mistaken, none of which are directly caused by poorly designed plastic parts? (Not counting issues that affect handling).

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I feel Tamiya materials are probably perfectly adequate, if we all stuck to using silver cans and 7.2 1400mah Nicd batteries. The designs are old with old power systems in mind. I like that the old designs retain the original plastics. We'll have to see what plastics are being used in the new CC02. No excuses for not having some quality modern materials in a brand new release. 

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13 hours ago, Mokei Kagaku said:

Choice of type of plastic to mold parts in is not just about the cost of the plastic itself. Tough and reinforced plastics cause a lot more wear on the molds, both because they have to be injected with higher pressure and because of their abrasive effect. That isn't so relevant for (relatively) small volume manufacturers like Associated and Schumacher, but it certainly is for a high volume manufacturer like Tamiya. As pointed out here already, Tamiya use high strength plastics in their TRF-models, but not just because they are more expensive and sold to more demading customers, but also because mold wear isn't so relevant for these low volume models.  For high volume models however, mold wear is of course an issue, so if Tamiya had used for instance fibre reinforced nylon throughout in the DT-02, DT-03, TT-02 and similar high volume chassises, the cost of repairing, maintaining and replacing molds would have been significantly higher and eventually handed down to the customers.

I agree with all this, but for one manufacturer left out...Traxxas. Traxxas seems to have mastered low cost, high durability plastics. Now, there are those that claim they can break a Traxxas vehicle with ease, but consider the speeds even a mundane 12T 550, 8.4V  Traxxas brushed vehicle travels at when it crashes. Those same plastics in a silvercan Tamiya would last forever and not stress crack around screw holes either. I just don't feel ABS is the right material for most jobs like Tamiya does. Its perfect for a DT02. But for a Top Force gearbox that might see track use or minimally higher power? Maybe there's something better without breaking the bank.

"Tamiya slop" I can deal with. Tamiyas were always easy to assemble. Earlier Associateds may have had tighter tolerances but only because you had to file-fit all the parts. What I don't like is seeing tapping screws rammed into ABS, instantly creating stress fractures and failure points from the get-go just waiting to pop out during normal use. If you're going to do that, built more mass around those holes to maintain structure. 

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I've always wondered why they didn't use more nylon. 

Just like the bumpers?  Grasshopper/Hornet/Lunchbox's front A-arms were also made from the same soft material, I think?  They'd bend, but not crack .  For tub chassis, that would bend too much.  But couldn't some nylon content help with cracks? (but hard enough for screws to bite)

Obviously for modern TRF, stiffer glass reinforced parts would suit better.  

I wonder if the ejection pin heads have to be bigger, because nylon is softer.  So...for older molds, adding nylon might not work, if the ejector pins were designed for harder ABS.  Who knows, the hardness might not matter much with some nylon.  No matter what the case might be, I wish Tamiya could pay a bit more attention to older re-releases too.   

 

 

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19 minutes ago, Juggular said:

I've always wondered why they didn't use more nylon. 

Well, to be honest, they do. You noted the Lunch Box/Hornet bumpers and A-arms. The Thundershot arms are and without checking, I'd bet the DF01 two-piece arms are as well. In this scenario, I praise Tamiya for making improvements over the somewhat brittle, rock-hard Hot Shot arms.

Let's use the Egress as an example as it has 3 plastics in its construction. The front and rear gearboxes are wisely upgraded to PC-GF or polycarbonate- glass fiber reinforced. All the suspension arms and bumper are PA or polyamide. Nylon as we know it is a polyamide. Maybe not the most rigid material for precise handling (though it could be considered a "high bite" arm) but certain durable. Then we move down to the knuckles, front arm retainer and rear shock tower mount. These are the shiny, hard plastics we associate with Tamiya. In this case, they are PC or a form of polycabonate. Many times what we think of as ABS in Tamiyas today is actually PC. PC is probably slightly better than the old ABS but still not a great material for these applications.  But the Avante/Egress cars were low volume/high cost buggies so Tamiya could afford to use some better materials that, in the case of PC-GF, is harder on the molds.

Incidentally, Certain plastics on the TXT-2 were subtlety upgraded from the TXT-1. Same parts, just better, reinforced plastics. 

So they can do it, but I feel they still over-rely on PC/ABS in applications they shouldn't. However @Mokei Kagaku points out an important fact to consider. If parts are affordable and available in the home market of Japan, there is probably little incentive to improve for the rest of the world. I doubt Tamiya cares/cared too much if someone trying to compete at the club level with a Dark Impact can't make it through a race without parts shattering because its made of acres of the shiny black plastic and not something superior.

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Really great discussion here, it made me think a bit about Tamiya timeline, some particular releases and the TRF brunch.

Well, also a personal reason. Some of you know i really like TR-15T and brother and sister, the Dyna Blaster and Dyna Storm. The TR was released in 93. (TRF came late 90s, right?) Great material, fiber reinforced plastic trees, hard aluminum, carbonfiber, some nylon parts, really a lot of different and great materials. With this spare parts it was possible to hop-up the both Dynas to the next level. Dyna Blaster out of the box is also a ABS monster, no excuse (but best design!)

Anyway, if they would have continued with this TR-15T materials and the general idear of these models (excluding nitro motor), there would have been a bunch of great and reliable models, isnt it?

 

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Speaking of materials, this happen this morning:

48692989068_5858b1ff7e.jpg20190907_095147 by Scott Weiland, on Flickr

Hotshot re-release purchased new about a year ago and assembled, but never ran by an individual who sold it to me. This is the buggy's second run (bone stock with 540 silvercan and all) on a flat baseball diamond. Never jumped or crashed. I was leisurely cruising around the bases, actually enjoying the simple pleasure of seeing it in operation when I lost steering. Like all of my cars, kept in climate controlled house away from UV. Some days (or months as its been going) I just can't win :P. Admittedly, since I didn't assemble it, I wasn't able to do my usual hot screw method I've adopted from others which may have stress relieved the part a bit. Here's a perfect example of incorrect material usage. Looks like Kyosho was wise to use alloy in this area on the Optima.

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Tamiya the kings of ABS! ...they do use some new plastics some times in kit's now but always still have ABS they really need to start producing all the kits in modern day plastics.

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Another excellent thread guys 

It’s relatively easy to reverse engineer why Tamiya do what they do re plastic composition / use  - cost, mold wear, spares revenue, simplicity, inherent obsolescence etc

What’s wholly misplaced imo is Tamiya’s lack of ambition / quality in off road

Not least because it fails to underpin the brand we all love ?

The solution is taking TRF insight back to off road - and making an expensive / customisable vanilla kit we could love out of the box 😬

Shelling peas with crap materials is currently poor reward for the faithful ...

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