Introduction: Grippy Robot Wheels

Picture of Grippy Robot Wheels

While trying to build a mini-sumo-robot, we found it difficult to get nice grippy wheels. So if we can't buy it, we will build it! In my research on Instructables I stumbled on the oogoo "movement"; https://www.instructables.com/id/How-To-Make-Your-Own-Sugru-Substitute/
I had some experience with silicon but that was not all positive; https://www.instructables.com/id/Arduino-Watch-with-Nokia-3110-screen/
Especially the time it took the silicon to set was a real challenge for my lack of patience. I tried making a wheel with just silicon sealant but the oogoo version came out so much nicer.

Step 1: You Will Need

Picture of You Will Need
You will need

For the rims
  • some board material (I used a hard plastic foam)
  • glue

Tools
  • holesaw
  • big hole drill (a Forstner bit)
  • drill
  • drillpress (a hand drill won't do this time)
  • saw
  • sandpaper


For the tires (Oogoo)
  • silicon sealant
  • corn starch
  • oil paint (if you want to color your tire)
  • release wax
  • mold (I used a PVC pipe-cap)
  • plastic cup
  • nut, ring and bolt
  • some water

Tools
  • spatula
  • caulking gun
  • air compressor (helps to get the wheel out of the mold)
  • scissors

Optional
  • spray-paint
  • primer
  • degreaser

Step 2: Designs the Rim(s)

Picture of Designs the Rim(s)
Before you can start with the rims you need to decide on some things:
  • How big do you want your wheels
  • What is the diameter of the axle
  • What is the size of the ring that you will use to mount your wheels
  • How wide do you want your wheels
  • What kind of board do you have
My choices:
  • Big: 75 mm
  • 15 mm wide
  • 25 mm rings
  • 5 mm axle
  • 7,5 mm board
The rims need to be smaller than the wheels (for obvious reasons). The size of the rims will probably be dictated by the size of your hole saw. Mine ended up about 45 mm. The bigger your rim, the smaller your tire will be. You can't make your tires to small or you won't be able to get the oogoo in-between the rim and the mold.
The width of the rim will be dictated by the thickness of your board. It can be 1 x the thickness, or more times. For my wheels it will be 2 times the board thickness.

I started by cutting a strip of board material just a little wider than the hole saw that I am going to use.

Step 3: Making the Rims

Picture of Making the Rims
Cutting the backplate
  • Put your board sturdy in the drill press. (Use a clamp or something)
    Put something underneath the board to protect your hole saw
  • Drill the centre hole in the size of the axle (5 mm in my case)
  • Do not (re)move the board
  • Remove the centre drill from your hole saw
  • Change the (5 mm) drill for the hole saw
  • Cut out the backplate of the rim
  • Nock the backplate out of the hole saw by unscrewing the centre piece and nocking it on the table (that worked for me)

Cutting the front plate(s)
How many front plates you will need, will depend on how wide you want your wheels to be. My wheels will be 2 times the thickness of the board so I will need just one front plate.
  • Put your board again sturdy in the drill press with something underneath the board to protect your hole saw
  • Drill a hole the size of the ring that you will use to mount the wheel on the motor.
  • Do not (re)move the board
  • Change the drill for the hole saw
  • Cut out the front plate of the rim
  • Take the front plate out of the hole saw by putting your finger in the hole and pulling

Step 4: Finishing the Rims

Picture of Finishing the Rims
I smooth out the plates using a belt sander but you can also use simple sandpaper.
By putting a screwdriver trough the hole and holding the plate 45 degrees to the belt, the plate will spin and I won't produce flat spots. If you use this method, be careful not to burn your fingers.

Glue the plates together
  • Sand the plates smooth
  • You can sand the rim a little bit in an angle to hold the tire in place
  • Glue the plates on top of each other. (use the glue that is suitable for the material you used)

Paint the rims
Painting the rims is an option
  • degrease the front of the rim
  • find a good location to use spray-paint
  • spray the front with a suitable primer
  • when the primer is dry spay with the color you like
  • If you want, you can also paint the back (I didn't)

Step 5: Prepare the Mold

Picture of Prepare the Mold
Find a mold in the size you need. I've found an end cap that was a nice size. It needs to be a little bit flexible. Not a lot, but more than glass or ceramic.

The hardest part is finding the centre of the mold.
  • drill a hole in the middle of the mold in the size of the axle
  • rub wax (or an other loosing agent) inside the mold
  • put a bold trough the hole (use a bolt in the size of the hole)
  • put the rim on the bolt with the backside up (the paint must be dry)
  • put a ring and a nut on the bolt to secure the rim in place

Step 6: Mix the Oogoo

Picture of Mix the Oogoo
If you want to know everything about the mixture I used for the tires, you should read the Ible from mikey77 who came up with this recipe; https://www.instructables.com/id/How-To-Make-Your-Own-Sugru-Substitute/

But it is so easy to make that I will give the recipe I used.
  • put the silicone in a plastic cup
  • add a little bit of oil paint (only if you want to color the tires)
  • mix the silicone and the paint (do this in a well ventilated workspace)
  • add one part corn starch for one part silicone in volume
  • stir thoroughly (start slow or you will be covered in corn starch)

It is no problem if you realize that you didn't make enough, you can easily add more when you used this batch.

Step 7: Filling the Mold

Picture of Filling the Mold
There is no easy way or trick for this.
  • Just get the oogoo in the mold.
I used a small strip of aluminum because it is small enough to fit in-between the rim and the mold.
Try to get al little air bubbles in as possible. This will be hard.

When you managed to get enough oogoo in the mold,
  • use a spatula (or putty knife) to smooth out the top and remove excess oogoo. The more attention you will put into this, the better your final product will look.
  • Let it dry for a couple of hours (or overnight)
The drying time varies with the mixture of oogoo, the temperature in the room and the moisture in the starch and the air. For me four hours was enough to dry the oogoo.

Step 8: Release the Mold

Picture of Release the Mold
It can be quite a trick to get the wheel out of the mold, but with some tips it is not so hard.
  • take the bolt out of the rim and the mold
  • remove some excess rubber (this should be very easy now)
  • press the sides of the mold until some space occurs between the tire and the mold
  • put some water on top of the mold and work it in-between the wheel and the mold by pressing the sides of the mold
  • when you worked the water all the way around in-between the wheel and the mold, push on the bottom of the mold
  • to get the wheel out, put your finger on the hole of the rim and blow a little of air in the hole in the mold (with the compressor)
  • the wheel should easily come out now
Sometimes the air blows out the rim and not the whole wheel. Don't worry about this, you can easily take out the tire by now. You can glue the tire back on the rim with some silicone sealant.

Step 9: Put the Wheels on the Robot

Picture of Put the Wheels on the Robot
To finnish this wheel-project I put them on the robot in the making.

They fit the axles nice and snug.
  • put the wheels on the axles
  • put the ring in the rim
  • screw the ring on the axle

For different axles you might need an other method of assembly.

Hopefully I can show an Ible with the finished mini sumo robot soon!

Comments

Snortimer (author)2014-01-05

Nice wheels! Now I haven't tested (or even purchased) this, but Inventables.com has a micro-suction material that might be interesting to wrap around wheels.

JustinT98 (author)Snortimer2016-10-24

Can you post the link of the material in question?

kenyer (author)Snortimer2014-01-05

Thank you.
That would certainly be a nice idea but…. sticky tires are not allowed in the mini-sumo-competition.
They have nice stuff on that site.

chiobesek (author)2015-10-13

Hi! This instructable is awesome, I'm gong to do it for my robot but I want to know if someone can tell me more specifically what is the material for the rims, the "board material" or "hard plastic foam", I can't find the equivalent in Spanish, and Google is not very helpful with the images of the material. Hopefully someone can help me! Thanks in advance! :)

kenyer (author)chiobesek2016-02-23

Sorry that it took me so long to reply. (I somehow missed your message)

You could also use simply some wood or ply or whatever you can find. I used this because this is what I found, browsing our local hardware store.

chiobesek (author)2015-10-13

Hi! This instructable is awesome, I'm gong to do it for my robot but I want to know if someone can tell me more specifically what is the material for the rims, the "board material" or "hard plastic foam", I can't find the equivalent in Spanish, and Google is not very helpful with the images of the material. Hopefully someone can help me! Thanks in advance! :)

jleblanc10 (author)2014-08-20

Add silicone sex lube, primarily siloxane, to make it softer and stickier. You don't need too much. The more Mood lube you add, the slower it will set. You can use just a few mm thick coat of the soft stuff on the outside circumference and backfill with normal, stiffer oogoo after it sets

kenyer (author)jleblanc102014-08-20

Thank you for the tip. For the sumo-robot we can't make them stickier. There are rules for and we are already on the edge of how sticky we are allowed to get.

apburner (author)2014-07-08

I was thinking that a great though large wheel mold would be a can that super33 black electrical tape comes in. Just drill the center and I find that usually there is a divot in the center of those cans.

http://www.3m.com/product/information/Scotch-Super-33plus-Vinyl-Electrical-Tape.html

kenyer (author)apburner2014-07-09

An extra tip, I learned just a week ago: When you type a link in a reply and then select the link you just typed, a small menu appears where you can select the chain symbol to make the link really link.

kenyer (author)apburner2014-07-09

I have never seen those cans here, but they look like they would work great. (and you probably will have those for free left over from the tape, what is even better :) )

debrajk (author)2014-05-14

I suggest you enter this in the new wheels contest

kenyer (author)debrajk2014-05-14

thank you, but "old" instructables can't compete.

debrajk (author)kenyer2014-05-28

You can always make another wheel. A different design probably. put up a new i'ble and go for it....

TheMeltyBotBuilder (author)2014-03-11

does the oogoo bond to steel

No, it doesn't bond to steel. The connection should be made by making grooves or dents in the rim.

could you glue it on with epoxy or equivalent

You can always try, but I don't think that it will work.

TheMeltyBotBuilder (author)2014-01-19

awesome instructable, very useful. can the oogoo be any other colours?

Yes sure! We have them now in blue, green, orange, grey and red. It just depends on the color of paint you add.

mikey77 (author)2014-01-07

Nice.

A few things I have tried with Oogoo that you might be interested in:

You can increase the grippiness (coefficient of friction) of the wheel by using a 3 silicone to 1 corn starch. It will take a longer to set up, but it adds traction.

You can also increase the frictional grip by adding a few drops of liquid dish detergent to the initial mix. Don't know why it works, but it does.

Once you have a wheel you made that you like or you want to copy some other wheel, you can easily duplicate it by applying two coats of spray lacquer on the wheel. Once dry, you can then coat the wheel with enough Oogoo to make a mold. The Lacquer sticks just well enough to the Oogoo to make an excellent release that just flakes off when you pull it apart. Spray more lacquer on the mold, and you can cast more identical wheels.

kenyer (author)mikey772014-01-08

Thank you.
First we will see how our robots do with this wheels, but I am sure we will try to get an edge on each other by changing the formula of the compound. I will post what formula will work the best for us.

Everybody made his wheels now with the end caps as a mold, but when we are going to make new versions we might try to make molds out of the existing wheels.

Whenever we will find out something new, I will post it. I love the adding of oil-paint. It really finishes the end result. And it seems that it doesn't really matter how much you add exactly. The colors of different batches of oogoo are pretty similar.

adamw ROX OUT LOUD (author)2014-01-06

Very nice! Could this somehow be adapted to make treads? How flexible is the hardened product?

We are working on that. The product is a little bit more elastic than a rubber band. It feels like silicon backing ware (perhaps because it is silicon)
I will post when the treads experiment is successful.

kenyer (author)2014-01-05

The wheel-production is in full swing in our mini-sumo-club

Kiteman (author)2014-01-02

Looking forward to the full sumo write-up!

kenyer (author)Kiteman2014-01-02

The first prototype already stays nicely in the ring :)

Verticees (author)2014-01-02

I saw that it was quite difficult to get the oogoo out of the mold! In mikey77's instructable, he mentioned that adding Vaseline to the part being used to mold helps make it easier to get the mold object out. Thanks for the awesome Instructable!

kenyer (author)Verticees2014-01-02

That is true. I forgot about that. Thanx.
The wax and air also works very good.

tinker bot (author)2014-01-02

Your "Big hole drill" is called a Forstner bit

kenyer (author)tinker bot2014-01-02

thanx

ASCAS (author)2014-01-02

Thank God I found this guide! You've just made the best Banebot wheel clones ever!

I wanted to buy Banebot wheels but they were a bit expensive. My teammate uses Banebot wheels for sumo competitions he usually wins in the 3kg devision, I compete in the Mini division. I've been planning to make a 3kg Japanese sumobot (low diameter & wider wheels). Before the Japsumo attempt, I needed to learn how to make custom wheels. I would usually find Polyurethane based wheels but not silicon. Luckily your guide answered all my questions.

Thanks for posting! I <3 your guide.

kenyer (author)ASCAS2014-01-02

cool! We are just starting with mini-sumo's here in the Netherlands. As far as I know there is no existing competition. So when I have questions I might come to you with them if that is OK :)

nerd7473 (author)2014-01-02

cool man

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Bio: I'm a social-worker, working with 12 - 23 year-olds. I used to be a printer and I worked voluntarily in Romania for a couple of ... More »
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