Would it be possible to cast wheels onto wheels>? drill a bunch of holes to lock it on.
2 Likes
Thats what I did with the latest casts
3 Likes
Today I joined your casterâs club 
Why not just bying some? Well, I did, but they didnât quite fit to my DIY Hubmotor (too tight), so I had to DIY again 
For the outer ring of the mould I used an ordinary aluminium pipe and machined a simple ring groove into another aluminium part for centering the outer ring and the inner one (being the core of my sleeve).
Basically I used visnu777âs manual and same PU.
-
Application of release agent on mould (Spray, distribute with brush, spray again, wait for 30 mins):
-
Assembly of mould, stiring of both PU components for 3 mins, casting slowly to prevent air bubbles)
-
Curing for 2 days, easy removing from mould:
-
Some tempering at 65° in order to further improve physical properties
-
Magic amber sleeve is done
@visnu777: Thanks a lot! Without your post here I wouldnât have even thought about casting wheels or sleeves at home at all! 
12 Likes
Wow, great job! How does it ride?
Stupid me, you didnt try yet right? Thought the bubbles were dirt
3 Likes
I didnât try yet, because the second sleeve is still curing. But with 10mm PU I expect it to be as hard as the sleeves of maytech and Co 
This time I tried to pour it even slowlier than the first time, to prevent those bubbles. But they arenât as bad in reality as they seem on the picture. The lamp amplifies them a lot 
I was too stingy to spend another 20⏠for the black pigments. I guess, if the sleeve was coloured you wouldnât notice those bubbles at all
2 Likes
Maybe this is already known (didnât read the whole thread), but the conclusive way to remove bubbles is to put the whole assembly in a vacuum chamber after pour.
Iâve made a half dozen sets of Smooth-On urethane 30 duro tires with 3D printed molds and theyâve all turned out excellent for their intended use.
2 Likes
Yeah thats looking pretty pretty, doooood.
Awesome job! Curious on how they feel in the streets.
1 Like
Yeah, what @sleepless said and/or mix up the thane under vacuum, so there will be no bubble from the beginning if you let it flow slowly into the mold.
PIGMENTS? I would use tons of glitter bc im brave 
1 Like
Yup, thatâs what smooth on advices as well but for one set of sleeves I didnât want to buy another machine or tool. My little flat and cellar is already stuffed with tools for my boards
Donât want to overtax my girlfriendâs acceptance 
3 Likes
So I wanted to do some experiments with my own cast wheels. However top problem seems to be cores. Does anyone have access or know where to get fresh kegel plastic cores?
Iâm running into dillema where I could cnc them from aluminum, however bonding aluminum to polyurethane reliably has been hard in past, itâs a hit and miss really. Another option I see would be using lathe and just making my own specific version for 3d servisas pulleys. In that case, core material would be something plastic based. Does anyone have any experience in this?
1 Like
I totally agree. One of my sleeves came of the aluminium at 40km/h. Luckily it only loosened a bit and didnât fly of completely. Now I glued it with special PU glue to the aluminium. Test coming up this weekend
In every case I would really recommend to machine deep grooves or holes to interlock PU and aluminium in addition to grinding the surface for good adhesion.
Have you considered 3D printing for your rims? There is some glass fibre reinforced PA which is quite tough.
2 Likes
If you look at the clean cores you can see a lot adhesion is a mechanical bond. Those slots around the surface are for the urethane to flow through and really lock to the core.
5 Likes
After some testing with heavy strain for the wheels (speed, burnouts, carving) both sleeves loosened from the aluminium.
The glued one went of almost completelyâŚ
âŚwhile the other one just detached in a few spots (dark areas):
So I added thousands of flat holes and grinded the aluminium with very rough sand paper to achieve better adhesion and form closure.
I hope this will do 
(2 days curing time 
)
5 Likes
Printing any of those reinforced PLA materials is quite messy. Glass reinforced PLA loves to warp, it slowly erodes 3d printer nozzle and is costly. Otherwise itâs pretty much best 3d printing has to offer. Will probably do couple of tests. Friend tried making wheels for rollerskates out of regular ABS and PU, he did about 10kmâs without problems.
Are you sure the problem is with the surface area and not the formula itself? Ive seen sleeves holding onto less material than that.
I am quite sure that the formula is fine. I used very sensitive scales. On the second wheel, where the PU only came of in a few spots, it was very difficult to peel it off completely.
I blame the oxid layer of the aluminium. It seems that I didnât sand it properly enough everywhereâŚ
Aluminum likes to make oxide with air almost instantly, based on other pictures you sent, that could be the cause. Make sure you check if there is no contamination present from something simple as mixing stick. At current state I would start doing small scale tests before trying to case new sleeves.
