Marui Big Bear tires - let's CAD :)

[silvertriple]

Finalised the CAD model with what remained in the todo list




- tolerances for assembly was added
- features to ease the unmoulding

I've read a lot of things and searched for a lot of informations, up to a point some people are now contacting me to sell some products... Let's see if I can find someone willing to showcase their product for free

[Dadio]

Your going right off the map with this project , all I can offer is to wish you luck .

[silvertriple]

Your going right off the map with this project , all I can offer is to wish you luck .

yeah, I know, totally off the board . Let's see if this can lead to something, that would be nice...

On the other side, my real target is to play around with biggy tires (for the time being, toying with big bear tires is just fun and unrealistic due to their size (i've check for a resin printer able to print those the initial investment is huge and not in line with what I was considering to do on my own... So for the time being, they will be kept theorical.

For the buggy tires, I started to analyse how to set a center key and the number of component required. That's complicated.The minimal number of parts we should consider for the center floor is 8 parts... Challenging, at least.


That being said, at this stage I work with some theorical elements. And I love theory. But I also love practice. And while in theory practice and theory are the same, we know that in practice, this is not true
At least one of the contact I've made would lead me to get at least better knowledge of what is needed for a realistic mould as this company is doing Vintage 1/8 tires, and that could help to make mine much more realistic and easily usable at the end.

And ultimately, success is only matter of trying hard enough. At the end, that's all about this : Trying

[silvertriple]

Enjoying the air conditionner inside while it is 35°C outside...
And modeled the Super Wheelie tires




Need to get back to the Shogun tires work later... This is a brain breaker, and it's sunday, I keep this for a day within the week

In termes of tires for the Marui range, I'm still missing Front and Rear for Hunter and Galaxy, the four different tires of the Samurai (if we don't work out the lettering, we can do two and their mirror, but the lettering need to be included after the mirror, so it's four), and lastly the very easy Onroad ones from the Coors ...

[silvertriple]

The almost complete Marui tire collection in CAD (the only missing one is the foam tire of the Coors in onroad version)

[silvertriple]

I completed the collection with the Tbird coors tires...


Amon my research I started to talk with someone on another forums about moulding tires. From the discussion, I'm now convinced it is possible to do with a single part for the center mould. The flexibility of the tire should be enough to get the center part out.
I'll need to work out the mould for one of the tires to try. I may even try with FDM printed mould first.

For DYI, Vytaflex 40 (soft) and Vytaflex 60 (medium/hard) might be the right target products for the tires compound. The products are not that expensive, pot time about 1 hour cure time about 16hours.
Needs to work this out

[silvertriple]

Yesterday, i met the people of Loisirs Creation RC (https://www.facebook.com/Loisirs-Cr%C3%A9ations-RC-106701397927717). They are a very small french company, and they put on the market vintage 1/8 buggy tires for 50mm wheels last year. They are doing things with a real passion, and they are really nice people, and I spent the day with them to discuss my ideas and learn about making tires (you can find their products on ebay : loisirscreations2009).

The discussion confirmed some of the things I had in mind: I need to rework my moulds to get this done with urethane resin... And from the discussion I learned some tricks about how the real mould is done and how the the tires are done with a injection press. I won't have access to this, but from both this and the discussion on another forum with NickCNC that should help me to do something...

[BillKrueger]

I just picked up two of the big bear kits with old old tires on them, you have me very interested in your results!

[silvertriple]

I just picked up two of the big bear kits with old old tires on them, you have me very interested in your results!

Thanks for the interest! I'm not yet there : I decided to start with smaller tires first, and i'm currently designing a mould for this purpose. Once the work is ready, I'll order the mould print in resin or PA12 (not sure yet which one I'll do, there is benefit to both), and i'll do test on this with Vytaflex 60 resin compound. If this is satisfactory, I'll move to Big Bear tires... It may take a few mounts to get there...

[BillKrueger]

No problem, I understand these things take time and money. I have recently acquired two big bears, so original looking tires would be nice. Until that day I may try printing out an adaptor.

I appreciate all the work you've put into this project.

[rc10nick]

Amon my research I started to talk with someone on another forums about moulding tires. From the discussion, I'm now convinced it is possible to do with a single part for the center mould. The flexibility of the tire should be enough to get the center part out.
I'll need to work out the mould for one of the tires to try. I may even try with FDM printed mould first.

My ears are burning

My vote is going the FDM route at first. It's a safe, cheap, and low risk way to start playing around with molding tires and as you've seen it's been working for me just fine. I'm not using any special filaments or high res slicer profiles. Just PLA with a 0.4mm nozzle and the standard 0.2mm layer height. I've also accidentally destroyed plenty of molds so if I was paying for a print service to make them for me I'd probably be bankrupt by now (that might be a bit of an exaggeration).

Also, if you're interested I have my Mini-B tire molds up on printables. It would be the fastest way for you to get some experience under your belt with making tires which is invaluable.

[silvertriple]

Amon my research I started to talk with someone on another forums about moulding tires. From the discussion, I'm now convinced it is possible to do with a single part for the center mould. The flexibility of the tire should be enough to get the center part out.
I'll need to work out the mould for one of the tires to try. I may even try with FDM printed mould first.

My ears are burning

My vote is going the FDM route at first. It's a safe, cheap, and low risk way to start playing around with molding tires and as you've seen it's been working for me just fine. I'm not using any special filaments or high res slicer profiles. Just PLA with a 0.4mm nozzle and the standard 0.2mm layer height. I've also accidentally destroyed plenty of molds so if I was paying for a print service to make them for me I'd probably be bankrupt by now (that might be a bit of an exaggeration).

Also, if you're interested I have my Mini-B tire molds up on printables. It would be the fastest way for you to get some experience under your belt with making tires which is invaluable.

Thanks Nick... I saw your molds on Thingiverse. My meeting with the Loisirs Creations RC team gave me some ideas as well. if you have seen my profile here, you may have seen I have a lot of cars which may be waiting for tires... I'm lucky enough to have found some samples of tires in good state (exception made for the big bear which was the one that I did not have a sample, which means I could not make the measurement myself). I will try by one where I need quite a few set. I chose to start with the Marui Shogun tires. I'm working up the mould design currently. I have doubts that external mould in 2 parts would work for 2 reasons :
- printing half parts mould would require supports in the mould area
- I have doubts on the unmolding

Both those should not be an issue for a Big Bear tire. For most of the tires with spikes, the first element is going to be an issue for FDM printing as supports would be required on the internal side of the mould (I have some plans to improve the printer on this aspect, but i'm not yet there - far from it). However, this won't be an issue with powder based printing process (it might be a good fit for this in MJF or SLS). My plan for FDM is to print the tire thread in 4 parts to remove the overhang issues. I designed the mould accordingly: in total the external side is 6 parts (sides + tire thread in 4 parts). Center is going to be one part. I'm planning for air input to ease the removal closed by the lock I'll use to get the center part in place. Obviously, this is based on what I saw from your own work and what I see from my meeting with Loisirs Creations RC... The experiment will allow me to close out some idoubts, and also ensuring we can get a tire without air bubbles (and from both your own exp and what I was told by Loisirs Creations RC, it looks to be just a question of pressure at the end...)

May be i shoud get your mould and just try, but I would still require to work my own mould to learn myself. Thanks for the proposal

[rc10nick]

Yeah, compared to the style of tires I've been making those big knobs on your tires might be a bit harder to de-mold with just two outer mold pieces. With a softer rubber you could risk tearing treads off.

I suggested trying my molds because the tires themselves are so small that you'll hardly use any resin trying them and I think that would be worth it to get some hands experience working with the resins and figuring what does and doesn't work before you commit to something bigger. Alternatively you could start out with a slick tire for one of your cars. They're easier to design, print, and mold and there's less that can go wrong. My very first tires were slicks and once I got comfortable with them I moved on to treads.

[silvertriple]

Yeah, compared to the style of tires I've been making those big knobs on your tires might be a bit harder to de-mold with just two outer mold pieces. With a softer rubber you could risk tearing treads off.

I suggested trying my molds because the tires themselves are so small that you'll hardly use any resin trying them and I think that would be worth it to get some hands experience working with the resins and figuring what does and doesn't work before you commit to something bigger. Alternatively you could start out with a slick tire for one of your cars. They're easier to design, print, and mold and there's less that can go wrong. My very first tires were slicks and once I got comfortable with them I moved on to treads.

There is two ways to learn from experience : doing with small step, or trying hard from first
I'll try with a 1/10 tire first. I have a mould design good now. I just need to succeed printing it correctly. I will take care of this soon. Once I will have this printed, it will be time to order the resin, and to build a vacuum/pressure chamber (have some cheap ideas for this, and I have no doubt this will work). The only doubt I have is about my vacuum pump : not sure it is powerfull enough. I have most of the required material already...

Now, the question is really about when I will have this printed : my printer is currently out of order. I need to deal with this first

[silvertriple]

Launched a print yesterday with the target to test print moulds for the Shogun (smaller than Big Bear, better for testing)... Print failed miserably as the nozzle is clogged midprint... I will need to unclog it before retrying this...