mattbrailsford
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.
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
)
I then cast the hole thing in silicone
Finally, I then cast the tire and tada
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
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.
So this is going to be the new mould
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.
And here is the complete mould
Here is a pic of the old tire (middle) a tire from the first mould (right) and a tire from the new mould (blue).
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?
Hey Mike,
They just pull on real easy.
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
Fantastic work!
Ok, another test tire hot off the press
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