[CADA] CADA General Discussion Topic

[Toastie]

16 hours ago, R0Sch said:

it's not true that ABS is one "well-known" material composition used everywhere. You can vary the amount of additives (UV-stabilizer, flame retardant = e.g. the chemical that causes yellowing on the bricks)  and use different amounts of recyclate. Also, ABS can be anything between 15% to 35% acrylonitrile, 5% to 30% butadiene and 40% to 60% styrene. So unless LEGO and Chinese brands use exactly the same pellet-supplier it will not be the same material. Even heating it to a different temperature and using different pressure will result in different mechanical characteristics of product.

Well, I'd like to challenge that, knowing a little about ABS, yellowing of plastic material, regarding reaction mechanisms - it is part of my daytime job. I am not saying that I know anything to the extent that it is "true". No way. However, there are few things, that the chemical industry delivers to customers that I know of for sure.

First: ABS is characterized to the "last digit", when it comes to "arriving at desired properties". Desired as in: You, the customer, provide a set of characteristics you want the ABS polymer to have after molding it with a temperature and pressure programmed adjusted process. The (usually large scale supplier) offers you a list of possible compositions. Then the trial and error process begins on your side - let's call it fine-tuning. This is up to you. In most cases, though, you get the (almost) right composition, depending on how "good" your list of your envisioned characteristics is, and the supplier said: Can be done. The molding process is up-to you, but the supplier of the molding machine certainly has a list of predefined temp/pressure profiles, at least for the later generations of machines out there. As ABS is all over the world since so many decades, companies have assembled good-sized databases of what mix does behave in what way when molded in a specific process. Making such a molding machine is one thing, knowing what it does with different starting materials is another. There is soft ABS, hard ABS, more dense ABS and so on and on; enclosures are made of ABS (many parts of my beautiful IBM XT from 1985, which has not yellowed a tiny bit; also my Atari 1040, which has yellowed to the extent that you could say it was spray-painted), and myriads of other things. And bricks, of course. You know all that, I know, I just want to put things into perspective.

I have read that TLG page you referenced a thousand times, I believe. Starting next winter, the chemistry department at my university offers a B.Sc. course "Sustainable Chemistry". In preparation for that, I was looking around quite a bit, and my beloved hobby offers a lot of things to discuss with regard to "sustainable". Well, ABS and all the other polymers TLG lists on that page are persistent (non-bio-degradable) and simply accumulate. It's the whole purpose of using them, they talk about that on the very same page: "...  to endure decades of play and be passed down from generation to generation." It is what we want. The only chance they (and competitors) have with regard to sustainability is energy/CO2 saving when making the pieces - if they, or better we, do not want to give up that they endure decades of play.

You are absolutely right: ABS is only one of the highly persistent polymers, TLG and competitors are using. For ABS, they list bricks; I could be wrong, but Technic beams looks very much like being made of ABS as well, among other Technic pieces. Axles would be dumb; the torque, TLG themselves will stress these with during QA, will tell the ABS supplier: No sorry, there is no ABS formulation that can withstand that torque. Well, so on to POM: TLG says: " hard and stiff material that is also flexible and strong". Hmmm. Hard and stiff = strong, but not that flexible. Tested it: Upon bending a 10L Technic axle, not much flexibility is seen (perpendicular to its main axis) before it disintegrates. OK, yes, I know, it is a page, marketing has made. And that is OK. POM though is another non-biodegradable ... etc. etc. Of course not. We don't want to look at rotting LEGO. And all the other polymers are not. They are made from different monomer formulations to match with the desired characteristic (highly flexible = PE, transparent = MABS, polycarbonate works as well, but is not listed under transparent but hinges).

And finally the yellowing. Man, so many articles delivering so many hypotheses ... I suggest though to drop the flame retardant argument, at least for bricks made after - let's make it 2000. The yellowing was presumably attributed to release of bromine, a brownish liquid at room temperature. That sounded good, but since 2000 "all" these bromine containing flame retardants (biphenyls and the like) suitable for usage in polymers have been phased out. The odor of bromine is, as the greek name bromos says, well, stinky. I bet you could smell bromine if a plastic piece yellows due to release of bromine. I guess the literature has settled on breaking remaining double bonds present (not in the aromatic ring systems) in ABS, which are then not easily saturated again (it is a solid material). The then "free" electrons - they are not free but delocalized - shift the absorption of light towards higher wavelengths = towards the red. And all that in the upper molecular layers of the polymer. In fact, when you ablate the upper layers (scratching is not good, it mechanically changes too many things) of yellowed ABS with nanosecond UV pulse laser radiation, the irradiated surface becomes swiftly white again, as the upper layers are non-thermally removed. Yes, did that in the lab, but it just proves that there was "something" changing in the upper molecular layers, which we already know. This also goes along very well with H2O2 mediated whitening, some call retro-brighting: H2O2 in aqueous solution (the higher %age the better) + UV light generates, among other things, OH radicals. These love electrons, delocalized or not, and thus saturate the formerly broken double bond by addition. Which removes the red shift and thus becomes "white" = non-absorbing again. However, only in the very upper molecular layers - if not the uppermost - since water or water/H2O2 solutions can't penetrate deeply into a polymer (on the timescale of treatment!). Maybe two or three layers, but that's it. Which also leads to the conclusion that it can't be bromine causing the yellowing, you would smell it, as it would sit in the upper molecular layer.

Well, that is what I arrived at, when plowing the literature for quite some time and doing some (non-conclusive) experiments. Who knows, it may be all garbage - maybe others have other information/references. I would love to hear of!

All the best,
Thorsten

Edited February 9 by Toastie
lower != higher

[R0Sch]

@Toastie Ok, cool knowledge base on your end. If you can now figure out how to permanently whiten my destroyed UCS sets, which I treated in H2O2, I buy you "ein Kasten Bier", because retro-brighting is unfortunately only temporary. In fact, the pieces look worse after a couple of month because they were subjected to more heat during the whitening process.

[Toastie]

17 minutes ago, R0Sch said:

"ein Kasten Bier"

Ouuu - Flensburger OK?

 

You are talking about white pieces, right? Colored pieces are so much more difficult, as it depends on the "pigments" or "dyes" they used for coloring the polymer - you can easily oxidize these to colorless as well ...

OK, when using H2O2 for retro-brighting, you don't need any heat - but UV light ("sunlight" slowly does it, but sunlight has more than 90% of radiation causing heat rather than H2O2 dissociation) or UV LEDs - they do it. Next: As high as possible concentrated H2O2 solution. The higher the concentration, the lower the UV exposure time required - otherwise H2O2 begins degrading the backbone of the polymer itself, not just the reactive sites causing yellowing. It seems there are two threads currently (actively, there are numerous non-active) discussing retro-brighting (https://www.eurobricks.com/forum/index.php?/forums/topic/197611-questions-about-using-hydrogen-peroxide-and-other-methods-to-restore-colour-to-a-very-special-piece-expedition-balloon/) and this one - which may be prone to off-topic moderator flagging 

Vanish needs heat though to start producing active oxygen (= O atoms). Well, it is used in washing machines - and there is not much light in there. And sure enough: a) When the removal = saturation of active sites in the polymer is not deep enough, re-yellowing is swiftly occurring, b) when the polymer (as e.g. my Atari case) seem(!) to have many remaining double bonds - it simply will just start again. Depends on the ABS formulation they used when making the polymer. Some formulations are prone to yellowing (my Atari), some others are not (my IBM), and as far as I am concerned, this is due to the presence of non-aromatic double bonds in the outer molecular layers of the polymer.

Hmmm - that blurb does certainly not qualify for receiving the Kasten, does it?

Best of luck though - chemistry is fun, weird, but mostly experimental trial and error. Still in 2024.

Best,
Thorsten

 

[shroomzofdoom]

Just wanted to ask if any of the CADA designers have ever had occasion to use this part and if so, how did you use it?

I often pick up 3rd party parts from various places. These are CADA branded. I picked them up thinking I might try making custom portal axles but the spacing doesn't seem good for that. They seem like they might be useful somewhere and I have about 40 of them so looking for some design ideas.

[efferman]

37 minutes ago, shroomzofdoom said:

CADA designers have ever had occasion to use this part and if so, how did you use it?

it was in the white SUV, but i have forgotten in which function.

[Mikdun]

11 hours ago, Toastie said:

The molding process is up-to you, but the supplier of the molding machine certainly has a list of predefined temp/pressure profiles, at least for the later generations of machines out there.

The parameters are defined by the plastic supplier, not the machine designer. Often different brands of ABS/PC/you_name_it have significant differences with regards to the temperatures.

Then there are injection speeds profiles, post pressure profiles... 

And let's not forget the mould design (especially size and location of injection points), this can also ruin your part. 

Just my 2c. 

PS: Fun fact: back in the "old days" customers were very strict NOT to use regrinded material, as it was said to lower the quality. Now it is mandated to use regrinded/recycled material to be eco-friendly. 

[Aurorasaurus]

3 hours ago, shroomzofdoom said:

Just wanted to ask if any of the CADA designers have ever had occasion to use this part and if so, how did you use it?

I often pick up 3rd party parts from various places. These are CADA branded. I picked them up thinking I might try making custom portal axles but the spacing doesn't seem good for that. They seem like they might be useful somewhere and I have about 40 of them so looking for some design ideas.

Perhaps you could turn them into a sculpture, if nothing else?

[msk6003]

4 hours ago, shroomzofdoom said:

Just wanted to ask if any of the CADA designers have ever had occasion to use this part and if so, how did you use it?

I often pick up 3rd party parts from various places. These are CADA branded. I picked them up thinking I might try making custom portal axles but the spacing doesn't seem good for that. They seem like they might be useful somewhere and I have about 40 of them so looking for some design ideas.

As far as I know used least 2 sets. Alfa romeo F1 and DF-21D missile truck.

[Toastie]

14 hours ago, Mikdun said:

The parameters are defined by the plastic supplier, not the machine designer.

And what about the owner of the machine? "They" (TLG's research department) can surely fine-tune, couldn't they? I'd do it, if I were the owner. Secret recipes provide IP.

14 hours ago, Mikdun said:

Then there are injection speeds profiles, post pressure profiles... 

For sure! But again, that is part of the research of the owner of the machine, isn't it?

14 hours ago, Mikdun said:

And let's not forget the mould design (especially size and location of injection points), this can also ruin your part.

And there we come to custom engineering. Precision is only one aspect, size and location of injection points, as you point out, is another. But these designs are again in the realm of the owner of the machine, right? I may piss off people here, but I had a "web-look" at the GoBricks site. These uncountable blocks of metal resembling "molds" ...

I am asking, because I am really curious (nerd here!). I gather my information from the web for sure, no real-world experience how molding really works. Yes, it takes a little longer, as I am not fine with one reference only, and I like to see some consistency, coherence and logic. The only field, I feel somewhat confident, is chemistry, polymers, companies in that field. And OK, maybe some >limited< machining experience; we need to make optical and vacuum parts that rely on the micron scale and below in our research.

Way more importantly: Thank you a lot for your insights, which I sincerely value!

All the best,
Thorsten

[Toastie]

14 hours ago, Mikdun said:

Now it is mandated to use regrinded/recycled material to be eco-friendly.

Damned, forgot: The TLG website talks about attempts to do exactly that. I believe - just from reading between the lines of this TLG text:

"In 2021 we had an exciting breakthrough and created a protype brick made from PET plastic bottles. However, after two years of continuous development it did not deliver the overall carbon reduction required to realise our ambitions" (https://www.lego.com/en-us/sustainability/environment/sustainable-materials). They continue with: "We’re proud of our achievements with the prototype and will apply the learnings as we continue to develop new materials and explore other ways to make our bricks more sustainable."

OK, my conclusion is: There is a breakthrough, and they are proud. But they do not use regrinded/recycled material to make LEGO parts. Which is absolutely fine - as >we< want that the parts "endure decades of play and be passed down from generation to generation." (same reference). See below for CO2 balance ...

It simply does not work that way. Chemistry-wise. Well, there is also Thermodynamics telling you: Yeah, can be done. But look at your energy balance. Hint: "The first and second law".

Well, that happens, when you "invent" (TLG did certainly not, they simply use it) a material, that is way down on the thermodynamic scale with regard to "endurance" and need ultimately clean and defined starting materials. Recycling without indefinite energy supply means: Degradation. Not tolerable in LEGO world.

Don't you agree?

With very best regards,
Thorsten

Edited February 9 by Toastie

[shroomzofdoom]

@msk6003 and @efferman

Appreciate the info!

The only place I was able to find this part being used was in the DF-21D missile truck. It's usage was definitely a portal axle but I don't think I'd have arrived at this design on my own.

I reproduced this from a speedbuild on yt:

Since it's hard to make out in my preferred 'all black' color palette...I also mocked up up a version using trans clear where the CADA part can be seen as the only black part:

 

With all of the spare time I had left over, I even made the sculpture for @Aurorasaurus 

Edited February 10 by shroomzofdoom

[Mikdun]

On 2/9/2024 at 11:30 PM, Toastie said:

that is part of the research of the owner of the machine, isn't it?

This is where all "magic"  happens. And it's kept close to the chest.

On 2/9/2024 at 11:30 PM, Toastie said:

I am asking, because I am really curious (nerd here!)

I'm sure you do realize that it takes years to got the knowledge. Just like in the chemistry field. But you are welcome to ask.

On 2/9/2024 at 11:46 PM, Toastie said:

Well, that happens, when you "invent" (TLG did certainly not, they simply use it) a material, that is way down on the thermodynamic scale with regard to "endurance" and need ultimately clean and defined starting materials. Recycling without indefinite energy supply means: Degradation. Not tolerable in LEGO world.

I'm not that deep into chemistry, so I may be wrong, to me every time plastic is processed it get a bit worse.

OTOH using regrind of virgin material is not easily detectable. We had such experiment done: external lab was not able to tell if the part is made from virgin or 100% regrind material. After more cycles it most likely will be.

Currently there are plastic materials with guaranteed % of regrind, as well as made only from recycled materials.

And we all noticed change of material for black friction pins. What exactly was changed is unknown.

[R0Sch]

On 2/12/2024 at 1:33 PM, Mikdun said:

And we all noticed change of material for black friction pins. What exactly was changed is unknown.

I think they just changed the material from PA to POM. You can hear the difference by dropping them on the table. The old pins made a nice clicking sound when fully inserted, these new pins are soft and garbage. They deform just by looking at them. I think part re-usability and durability will be a big topic with more modern sets. Yes, the older parts had a tendency to break under load and left on shelves too long, but at least the clutch power would not drop to zero after a few inserts. Gear skipping is another consequence of the material change.
From what I can see CaDA is still using the "classic" materials for pins, axles and gears.

[2GodBDGlory]

2 hours ago, R0Sch said:

I think they just changed the material from PA to POM. You can hear the difference by dropping them on the table. The old pins made a nice clicking sound when fully inserted, these new pins are soft and garbage. They deform just by looking at them. I think part re-usability and durability will be a big topic with more modern sets. Yes, the older parts had a tendency to break under load and left on shelves too long, but at least the clutch power would not drop to zero after a few inserts. Gear skipping is another consequence of the material change.
From what I can see CaDA is still using the "classic" materials for pins, axles and gears.

It seems like an unusual opinion, but I always find myself intentionally seeking out new-design pins whenever I need a solid connection in a model! Maybe it's just because they're newer and hence less abused than my other ones (I've reused the same parts in LOTS of models!), but their lack of a center slot makes me hopeful that they'll hold up a lot better long-term. I've probably scrapped >100 old style pins, and I'm hopeful that the new ones will be better

[Aurorasaurus]

On 2/10/2024 at 2:05 PM, shroomzofdoom said:

With all of the spare time I had left over, I even made the sculpture for @Aurorasaurus 

Haha, nice!

[dolfijn999]

Speed Build Mazda 787B | CaDA C55029W 

Speed Build Military Crane Truck | CaDA C61507W

 

[nintiendo]

On 11/6/2023 at 10:46 PM, brickphisto said:

I am happy to present my third CaDA model: Citroen C4 WRC officially licensed by Citroen. It is my first model which has been designed from scratch for CaDA whereas the classic sportscar and the London Taxi were based on older mocs. The scale roughly matches the scale of most Creator Expert/Icons cars.

Functions are rear suspension, independent front suspension, steering operated by steering wheel, working fake engine, opening doors, bonnet and trunk.

The model can be motorized using the CaDA battery box/receiver, an L-motor for propulsion and a servo for steering. Motorizing the model is a little more complex but also far more mature than motorizing the C61045 classic sportscar.

 

I have this one but still don't have a chance to unbox it :). I must admit I don't know much about this car as well as Citroen brand, I simply like its hatchback form and multicolor body (different brick colors, not stickers). Don't know if it runs fast enough as what I remember aboutall LEGO cars is they're all slow even sport/racing ones :D

BTW, I'm curious if there is any found building issues/fixes of this set. Thank you.

[sp1984]

Hello

question about linear actuators.

Does CADA technic linear actuator is compatible with Lego Technic?

Is it well designed and smooth operation?

Found one here:

https://decadastore.com/products/cada-10-15m-middle-hydraulic-cylinder-jv9033

it is pretty cheap (1 euro per one piece) so I am afraid that quality maybe rather low...

Also does that shop seem legit?

Regards

 

[2GodBDGlory]

1 hour ago, sp1984 said:

Hello

question about linear actuators.

Does CADA technic linear actuator is compatible with Lego Technic?

Is it well designed and smooth operation?

Found one here:

https://decadastore.com/products/cada-10-15m-middle-hydraulic-cylinder-jv9033

it is pretty cheap (1 euro per one piece) so I am afraid that quality maybe rather low...

Also does that shop seem legit?

Regards

 

I can't speak from experience, but CADA sets, including ones with linear actuators, seem to be well regarded, so I'd assume they work alright! It does look like the official store, so it should be legit. I'm now eyeing up their XL linear actuators, since I've never been able to justify buying the Lego ones...

Maybe someone else can give you some more specific advice

[efferman]

8 hours ago, sp1984 said:

Does CADA technic linear actuator is compatible with Lego Technic?

Yes, and it works like the lego actuator, but the xl actuator von cada has a stud more stroke, but has the same length retracted. But, the pistonrods are not fully metal.

8 hours ago, sp1984 said:

Also does that shop seem legit?

it is the official CaDA Webshop, so you can thrust them.

[mla2]

17 minutes ago, efferman said:

It is the official CaDA Webshop, so you can thrust them.

They do share email adresses with third party spammers, at least that's what happened for me and @R0Sch so I recommend using a throw away address.

Edited March 3 by mla2

[sp1984]

Hey

Thank you for your replies. I need some standard size actuators for MOC's but Lego ones became scarce in my country and are in low quantities or/and rather expensive. So was thinking about that CADA as replacement.

 

[Sokolov Edward]

CADA has added several more models to the catalog of instructions. For Technics models, instructions for the C65011 dump truck have appeared. Unfortunately, we are unlikely to see instructions for the Mercedes C61503. The previously deleted instructions for La Ferrari C61505 are unlikely to return to the catalog. The Chinese competitor of CADA, the Mould King company, is still distributing all its instructions for top models too. It would be interesting to assemble a Mercedes yourself, maybe someone can share the instructions? 

[R0Sch]

https://decadastore.com/products/cada-assassin-xr-c61513w

Congrats @Pvdb!

Edited March 16 by R0Sch
added YT video link

[LvdH]

I was quite excited for that one, but $180 is quite a bit more than I was willing to spend for it. 

Also: those red parts which I guess are supposed to be the taillight look awful and should have been orange. The P1’s taillights don’t look like that. 
I think whoever at Cada turned it into an orange car didn’t realise that the original red version by PvdB didn’t have taillights built in.