Planning a 34" mini cruiser rebuild. This will be an improvement to my 34" hub board that I rode this past season. I rode that board a ton and and sadly the wheels are already pretty worn. So, I figured I could make a pretty decent board on a budget that would have a few improvements.
So far the components will be:
-34" double kicktail skateshred deck (I really liked this deck on my last build so I’m using it again)
-2x BKB 6354 190kv
-2x boardnamics mounts
-Raw Caliber 44s
-12mm 16t/36t gearing
The enclosure for this will be an experiment. Planning to vacuum form my own.
Not sure if I’m going to use the TB vescs. The form factor for 4.12 is really inconvenient. I don’t really want to use anything else though because it would be overkill. Still to be determined.
Going forward with the TB vescs, I designed a mount that would position the phase wires as low as possible to fit on the back of the board. Unfortunately sensor detection failed on the master. The problem is isolated to the master vesc so I can’t even run it in hybrid. I only used these for one season in BLDC mode, so thats a bit of a bummer. Looks like I will have to use a pair of focbox’s for the last time (so long focbox you were the perfect size esc).
(if anyone in the US is interested in these let me know and I will let them go cheap, senor detection worked on the slave).
Fortunately progress has been made on the enclosure. As I said before the plan was to vacuum form my own. The most difficult thing about that for me is producing the mold buck. I don’t really have a workshop or space to make a lot of dust so woodworking was out.
Thinking, I went ahead and designed one in Solidworks. I measured all of the parts and curvature of the deck to get a perfect fit.
…but how to make it
Against the better judgement of online tutorials and my colleagues I decided to 3D print one (out of PLA nonetheless). Expecting it not to survive, I covered it with a layer of bondo and sanded that smooth. After that I used some denatured alcohol mixed with two part epoxy. This helps to thin the epoxy enough so that it can be brushed on smooth. The result was a hard glossy coating, although this was only used as an extra measure and may have not made much difference.
I 3D printed the vacuum inlets; I ended up using my shop vac and house vac combined. Super easy and very quick for a perfect fit.
The first go was promising, although I had some major webbing in one corner. I think I went too fast and didn’t take the extra seconds to get a good alignment. You can also see that I had to make some relief cuts to get the mold out. Don’t forget to use your mold release, whoops.
Fortunately, after some quick repairs the mold was good for at least one more shot. It definitely suffered as I could see some of the infill pattern on the surface as the plastic drooped. A quick smooth over with bondo and it was ready to go again.
For the second try I made sure to have another set of hands to help. I also had a soaking towel ready in the freezer to help cool the plastic faster.
The result is near perfection and with mold release the mold just dropped right out.
So I am happy to say that it is possible to use a 3D printed mold for vacuum forming ABS!
Some notes about the setup:
-1/8in ABS sheet used
-Standard kitchen oven used middle rack (getting replaced soon anyway)
-Temp set at 300° and baked the ABS for about 8mins (about 5-6in of droop on a 23in x 17in area)
-3D printed mold used 3 layers on the sides, top and bottom. 20% infill
I borrowed a bandsaw to cut out the enclosure then traced out the foam gasket.
Used threaded inserts again. These are a pain to use and not very cheap.
The electronics all came together very snugly. I routed the phase wires through a printed riser so they’d be lower profile. I also ended up using printed wheel pulleys and 90mm clones. The kegels didn’t offer enough clearance with the @Boardnamics mounts.
Overall came together pretty well. I’ll have to do more test runs when there’s a warm day. Haven’t gripped it yet either. Got a laser coming, so that’ll be fun.