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Asked — Edited

Omnibot 2K Wheels

Hey Guys,

I'm just starting off a new project after I got an Omnibot 2k off ebay. I'll be creating a project page for it soon, but I thought I'd share a little bit of it now.

When I dismantled the bot, and gave it a clean, I noticed that the wheels were pretty degraded. I know josh can create new ones, but being new to this, I really wanted to learn something new, so decided to make my own mould.

What I did then, was to carefully remove one of the existing tyres and then used a sealer to seal all the cracks.

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I then setup a box for it, and also attached a kind of funnel to help pore in the ruber (turns out it wasn't that great, but you've gotta try these things :))

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I then cast the hole thing in silicone

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Finally, I then cast the tire and tada:)

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I think it worked pretty well. The only bad bit is that I don't think I mixed the rubber to cast the tire very well as it's a little sticky. But hey, not bad for my first attempt:)

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Fantastic !

Very nice work. I'm sure your going to have some orders coming in soon ... LOL. Keep up the good work.


Thats sort of how I do it. I use rtv silicon gasket maker and I can make grey red blue black ect

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Cool. Mine is meant to be blue, but it's actually translucent so you can't actually tell:)

I've found they seem to come out a little thinner than the originals for some reason. Maybe the weight of the silicone compressed it during casting, as it is a fair old chunk:) Still fit nicely though, and they come out in one piece which I like.

Do you know why they might come out a bit sticky? I think it's just not mixed enough, although I made a second after mixing for longer and that was a bit sticky too (not as bad though).


It may be the properties of your compound. I use a plaster of paris mold to cast new tracks from and ive done several sets for the members. Ive found silicon based compound is the best to use. Its not sticky when cured , stays pliable and does not rot. Also silicon is chemical resistant so cleaners wont turn your tires to mush like the original did. I have currently 3 orders of omnibot tracks im filling this weekend. Its a simple way to earn cash towards your project. That and I would loooooove to have copies (or originals) of omnibot 2000 arms and claw. If you can do that your the man!:) im looking for them for my second project bot dusty.

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Cool, thanks for the tips. I think I'm gonna give the instant gasket stuff a try. From my calculations, it's only marginally more expensive, but it sounds easier and a bit more reliable.

The next bit I'm tempted to try casting is the rubber on the claws, as they also seem a bit degraded, but who know, if I can nail the process, maybe I'll move on to bigger pieces. I'm enjoying the learning process that's for sure:)

Thanks again.



Hi Matt, very good work! I am anxious to see whether youll get to reproduce non-sticking treads! Awesome! Mike

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Well I decided to have a go at making a tire with no colouring, just the rubber components, and that one came out way better. After 24 hours it wasn't sticky at all, so I'm wondering whether it's my choice of pigment that is at fault.

I've ordered some instant gasket silicone though, so I'll give those a try next before I dabble with the colouring.

I'm getting closer:)


You will be happy with the gasket maker silicon. Just let it sit over night or at least 4 to 6 hours to fully cure and it will not be sticky at all if you wait a while before removing it from a mold.

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They look cool. I like the fact you can make 4 at once. I had to do them one at a time. Wasn't too bad though as only took 1 hour till they were de-mouldable. Sounds like it'll take a bit longer with gasket stuff, so if it works well, I might make another mould.


Well if its warm like outside in the sun with good ventilation you can peel them loose in a hour, but I kinda assume its cold everywhere and people are doing this indoors lol. You can put them in the oven at 100 degrees and they cure really quick.

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I live in England, so you can safely assume its always cold:) Do you know if it'd be ok to stick in the oven being a silicone mould? And is that 100 degrees C or F?


100F is safe and is usually one of the lowest temp settings on a standard oven.

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Cool. Well I'm hoping the stuff arrives tomorrow, so will report back if it does.

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Dang! Got the instant gasket stuff today around lunch time so thought i'd give it a shot straight away. As my mould is made of silicone, i gave it a good spray of a mould release spray and filled it all up. Unfortunately, 7 hours later, it looks like the spray did nothing, as i now have a glued shut mould. Gutted:(

I've got a load of silicone left from the first attempt though, so will set about creating another one. I think i can make it a bit better this time too, so will use what i learnt from the first one.

I think i'll just stick with the rubber i was using before though, as i was getting better and better results, so will just do some more experimenting.


That sucks man. I used plaster of paris to make a mold. It doesn't stick to that too bad.

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Oh well, all part of the learning experience i guess. I dont think the next mould will take that long to make anyway, so no biggy.

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So this is going to be the new mould

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I've gone for a round one with the centre cut out so that I don't have to use as much silicone to make it this time. I've also done away with the funnel as I really don't think it's needed.

I think I'm gonna go ask the company I purchased the rubber from what pigment they recommend so I can see if it's that that was causing the sticky issues.

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And here is the complete mould

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Here is a pic of the old tire (middle) a tire from the first mould (right) and a tire from the new mould (blue). User-inserted image

The new cast tire suffers from the stickyness again, but after checking the old tires that have had time to rest, the are feeling much better and are hardly sticky at all now, so I think a good curing period and they are fine.

I'm also wondering whether it could be caused by left over release agent from the initial casting as the first mould improved over time, so just incase I've given the mould a good rinse and once dry will see if that makes a difference.

For the tires I'm using some A5O polyurethane liquid rubber which is nice and flexible, but I'm gonna try some A60 and then some A70 to see how a stiffer tire would feel. I reckon the stiffer ones might be a bit more hard wearing and would probably handle traction a bit better. I'll be sure to report back once I've tried them.


Wow! These things really does look good! Have you tried and pulled them on onto the old wheels to see how they fit? Will you have to fix them with double-sided tape or do you just pull them on?

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Hey Mike,

They just pull on real easy.

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The great thing is, because I cast them in one piece, it casts the retaining blocks on the inside of the tire, so it's just like having an exact copy of the original tires. The rubber has plenty of strech, so they are real easy to get on.

Once I've tried the different hardnesses (A60 and A70) I'll pick the best one and I should have the perfect solution to replacement tires:)

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Ok, another test tire hot off the press

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It's been out of the mould for a couple of hours now and it's not sticky at all, so either the reduced amount of die, or the fact I washed the mould seems to have fixed the sticky issue (I should really try to only change one variable at a time :))

Anyways, I should hopefully get my sample A60 and A70 rubber compounds on Monday so will do some more test runs then.


Very cool matt! You will be out modding me in no time;)

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Hehe, I doubt it, your skills are mad. I'm having fun trying though:)

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Although, I could do with picking your brain about filling holes in my omnimc project thread;)

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Yay! The new rubber has arrived. Time for some experimenting:)

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Oh hell yea! Utter perfection

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0% sticky, and the new pigment I'm using as soooooo much better. Both the A60 and A70 work really well, but I think the A70 might be the best option. It's quite stiff, like the original tires, but still pretty easy to get over on to the hub. I'm hoping the stiffness also ads to the durability, and would make it harder to come off during action.

All in all, I'm really chuffed. I'm off now to go make a full set:)

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Hmm, actually, I've just done a slide test on my desk and it would seem the A60's offer a bit more traction. I may be inclined to declare those the winner.

Time for some traction testing:)


Awesome. Will you stick to green, though? If you have the chance to test the wheel on the base, let it do turns instead of just going back and forth. I learnt that doing turns puts much more stress onto the rubber treads than anything else. Keep in mind that the robot weight adds to the traction.

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Hey Mike, I'd be able to do any number other colours, I just bought green as a test:)

Thanks for the tips on best way to test. I'll look at hooking up the ez board in the next couple of days, and give it a try.

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FYI, i should be able to do Black, Blue, Green, Yellow, Red or White, and probably grey by mixing black and white:)


Great! I just wondered about that.

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Ok, so here is the full set of A60s. I will test these for traction over the next few days.

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Took a little longer to cast as I made a stupid mistake mixing 2 parts of part B, rather than one party of A + B. Meant I had to wash my mould out and start again. Doh!

On the plus side, I'm almost certain the stickiness from the first trials was down to contaminants in the mould, as the last tire I made from this batch was also a little sticky, which I think is because I had some remnants of the mess up left in the mould. I've cleaned it thoroughly now though with a q-tip, so should be good to go for the next batch:)


Wow I love the green color!

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Here is a quick vid of the tires in action Click To Watch Video They seem to work really well, no slippage on the hubs or anything, so I'd be tempted to call it a success:)


@mattbrailsford - Nice job on the tires! I'm wondering how difficult it would be to make tracks for the Wall-E U-Command robot, I have one that's almost complete, but one track is missing. What do you think?

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@charleybot I can't see why not, it's just creating the mould, so as long as you have one good one it should be possible.


@mattbrailsford I'm trying to locate supplies to do this, and being in the U.S. I'm not having much luck... Anyone know where I can get this stuff in the US?


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@charleybot you should be able to use any silicone mould making silicone for the mould. For the tire, you want to find a 60 shore liquid polyurethane rubber (this is the tricky one). If I had a u-command wall-e I'd give it a go, but I don't have one I'm afraid (i have some of the interactive toy ones, but I don't think they are the same. I also think there is some variation between the ones in the us and the ones in the uk)


@mattbrailsford Thanks for the info, i've been looking around and I think this might do it here:

http://www.uscomposites.com/moldmaking.html 75-60 RTV Liquid Urethane Mold Rubber

It down the page a little bit, seems like it would work but I am not sure, what do you think?

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@charleybot looks like it could work. Worth a try at $15. The good thing is, the mould is the most expensive part, so once you have that, you can experiment with casting materials, but from the specs, it sounds about right.


@mattbrailsford - thank you for the help with this, I think I am going to give this a try in the next few weeks, even though it looks like it will be a trial/error thing for me, it's easier than trying to find a replacement track/tracks for Wall-E:)

Thanks again

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@charleybot no problem. The trial an error is the fun bit, especially when you nail it:) Let me know how you get on.


The video looks promising. Let it run on tiles in the bathroom or outside on pavement to see if the treads get sanded off by that.

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Whoop! Got this guy in the post:)

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So now have tires in omni sizes too:)

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You might be able to find somebody with the shoulder spring you need to fix it here in the forum.


You need a spring? I may have one.

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I'm trying to cast the good ones, but if that fails, i would be needing some replacement ones yea. Both on the right arm are snapped. @troy you say you might have some?


I do have them but I don't remember which spring is for the shoulder and which is for the wrist. I think its the smaller of the two. Let me know which it is and I will send it.


just to make this clear, he needs the plastic part that connects the upper to the lower arm, which is sometimes called "arm spring" since the plastic kinda works like one.


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So is it the large gear (with shaft) on the left you need? I thought it may have been the spring that goes on the middle gear.

Btw those treads look awesome! I wonder if you are allowed to sell them in quantity on Ebay. May concern is that its a copy of patented work. If not they are truly worthy for public sale.

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Hey @troy, no no, it's these that I would need:

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RE the tires, I was thinking of putting them on ebay on a "build to order" type of scenario, but good point about making sure I'm not breaking any laws. I'll defo look into it. I could really do with recooping a little cash. This hobby is costing me a fortune:)


ohhh. I thought we were talking about omnibot 2000 like in the thread title. That teaches me not to only read the last page. :/ I don't have those unfortunately.

Yeah those treads will definitely sell because a lot of omnis sold on ebay have worn out treads.

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Hey @troy, yea, my bad. I got delivery of an Omnibot a couple of days ago, so went ahead and made some tires for that aswell, as like you say, they had perished too.


Hey Guys, I remember one member here posted he would still have some of these parts you, Matt, need. Maybe youll have to open up another thread and ask about it! @Troy: if you ever have gears from your Omnibot 2000 arm to pass on, let me know. I got spare gears from Josh already but I am still looking for another few to fix up another arm. Mike


Sure point out which you need. Im packing up my stuff right now for the move. All of the extra stuff is disorganized in a large zip top bag.:)


Well, I could have a use for just any part you wouldnt need anymore pretty much, since I have a few Omnis. Lower arm gears, upper arm gears, whatever you could pass on.... P.S. To prevent this from getting off-topic, just drop me a message: xxx

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Awesome news! I now have an email from Tomy granting me permission to sell my reproduction tires without a problem so long as I make clear they are in no way supported or affiliated by Tomy

Whoop whoop:)


Wow that's good news. Its always good to have it in writing. It also means you can make as many as you like!


That's great news, so when can I place my order:)


I may replace mine just for the color choices!

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Cheers guys. Thanks, I'm really chuffed. I was almost going to give it up as a bad job as it was going to cost me loads to hire a specialist to look into it, so when I got that email, I was well relieved:)

So far, I've got moulds for Omni 2000, Omni and Omni Jr robots so can do pretty much any of those. Price wise, I'm thinking the following:

Omni Jr = 4 per tire (8 per set) Omni = 5 per tire (20 per set) Omni 2000 = 6.50 per tire (26 per set)

All of these I can currently do in Black, Blue, Red or Green (I can get a Yellow too if anyone wants that). I'm working on Grey, but I have to do that by mixing black with white, so need to come up with a reliable way of mixing the colours.

If anyone is interested, let me know and I'll work out some postage.

I hope I can help bring some life bike to some awesome toys:)


That's the perfect place to advertise. So if someone sells an omni with bad tires they can easily find your produce in the same place.

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Yea, that's what I thought too. If it can earn my enough to pay for my habbit, I'd be happy:)


You could watch every omnibot and robie sr auction and send the winner an email letting him know you have new tires:)


Hey matt, how did you remove the threads off the wheels? Mike


Hi Matt, do you still have these for sale? I'd like a set for my omni bot 2000 and possibly a set for the Robie jr I just got.

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Hi Draken,

Sure do, checkout this post for a list of what I currently have https://synthiam.com/Community/Questions/2431&page=3 From the looks of it, I should have 1 set of 2000's and I have plenty of Jr's.

My email address is in the other post so drop me an email and let me know if / what you'd like.



@ mike , the treads are rubber so the stretch. Just stretch them a bit and slide it over the edge of the hub. The lip is only a couple mm high.