Seems a bit strange to name an esk8 build
But in an effort to follow the trend around here:
Night Train Concept
Loaded like a freight train
Flyin’ like an aeroplane
Feelin’ like a space brain
One more time tonight
This build started out (after accumulating some parts) with this name/idea in mind. For a little while anyway…
It never really related to an aesthetic, but the idea of a crazy loaded urethane build appealed to me. I’d seen ahravs mental 4wd builds and thought hey why not try to follow along with something like that. I was also a bit of a space brain at times during this build, went stupidly deep into learning new stuff making the enclosure, kind of on a whim…
But…I’m no speed demon. And like a few of you, my build budget is a little more modest. So a 4wd big(ish) battery urethane build, but on a relatively modest budget was my plan. Maybe not so crazy after all.
I like DIY and making stuff. On this build i had a few goals to try and up my DIY game.
Segmented flexible enclosure
Enclosure heatsinks and waterproofing
Wood veneer deck finish
A lot of stuff posted here is spread over my freesk8 workshop posts, but I’m shit at storytelling and pictures beat words so here’s some finished pics. Stats after.
(and then some drop downs for bits I made).
Deck - Hummie, bedliner & veneer finish
Enclosure - DIY segmented FG, bedliner finish
Battery - DIY 10s9p P26a, built into enclosure
BMS - nope, #fuckbms
ESCs - 2 / makerX DV4
Heatsinks - 2 / Infinitysinks, offset backplates
Drivetrain - 4 / BNM1 straight cuts
Trucks - Steel BN 270s, ceramic coated, on caliber 44 and randal 35 baseplates (TBC) and DIY wheelbase extension plates
Wheels - TB110 72a black (TBC)
Motors - 4 / makerX 6355s 190kV
Telemetry - Robogotchi
Antispark - the good(ish) Flipsky Smart one…?
Loopkey - always
Remote - Poastmote Puck
(parts TBC are fitted but possible to change)
Segmented flex enclosure
[WARNING: this is punishingly long]
(actually pretty appropriate)
Following the wisdom laid down by our wise predecessors (Deck and Enclosure before all else) I built this enclosure before really planning on anything else on the build. I had the Hummie deck and wanted to build a new enclosure for it, to hold at least a decent sized double stack battery. At the time, I was a bit bored and needed a project. So without really too much of a plan, I started making a buck.
After getting to this stage, where the length of the buck was generally based on the Hummie deck cutout length, I reconsidered my approach (it looked like shit) and decided to chop it up and make a segmented flexible enclosure. This meant a lot more work…
But it was fitting the board better and I was happy. Primed and sanded the buck to a smooth finish.
Briliant. A perfectly shiny painted MDF block of wood. Not really useful, so for my first time, I attempted to make a composite mould off the buck.
Mixed up epoxy, colloidal silica and pigment in a big batch, and slapped it onto a well prepared (waxed and pva coated) buck. Once that layer tacked I chucked on some fine fibreglass cloth and then with a watchful eye, I then spent the best part of a day sneaking away from the wife and kids to add fibreglass layers and epoxy and wait for the next tack stage. I also used some cool boat building core stuff to fill gaps between the segments. This was a pretty rough process but it seemed to work out ok. Pics:
In the end, I epoxied a bit of timber to the bottom of the mould and screwed on some cross members, because it was ‘difficult’ to de mould the buck.
Then I made a flange on the mould, to make my parts layup / vacuum sealing possible.
After all that, I had a decent mould so I made a part! Had a go with gelcoat for the first time, and just vac bagged the wet layup.
Couple of finish defects and I had issues getting all the layup done before my epoxy kicked, so I changed approach and decided to try resin infusion. Read some shit online, bought some tubing and new resin and had a crack. It was a bit daunting, but an exciting new process to try!
Successful infusion process gave me some inspiration, so my plans for battery and guts layout could start. Aside from that I made another part with infusion, using a gelcoat skin coat before the dry fabric layup, which turned out really well
After about three months, enclosure done!
Enclosure heatsinks and waterproofing
So my goal for this build was to try and make the enclosure as watertight as seemed practicable (or sensible?). To me, that meant motor, sensor, loopkey, charge and also balance plugs selected to be reasonably waterproof and sealed onto the enclosure with epoxy resin. Again, this was not a quick process but seemed to work out ok.
First holes for heatsinks, central on enclosure spaces, with custom offset mounting plates from @surfnacho so that the battery could fit
Then MR60/bullet connectors epoxied through the enclosure to allow plugging in on both sides for esc and motors phases.
For some reason I thought a flat mounted voltage meter would be cool, so I set that in, but it wouldn’t calibrate well so was removed and the hole filled with fibreglass.
Then bedliner on deck underside (after routing and CF skinning) and enclosure to match and give a better finish. Fucked up the bedliner gun settings and got a super heavy stipple
So my goal on this build was all electrics and battery fully mounted into the enclosure, sled style. P groups siliconed in place, all electrics fixed down, cables secure and all exterior plugs able on be removed so the sled could be unscrewed and removed easily.
Got my Sunnko modified to handle 0.2mm nickel better. (Not planning on that again tho)
Glued p groups in with neutral cure and made series connections
Balance wiring, esc power harness and some fishpaper in place. Siliconed in all loose wiring.
Then foam padding/packing to fill gaps above batteries within the Hummie deck recess.
Edit - found one more waterproofing pic, with more foam padding, butyl tape on deck and enclosure flanges, before sealing her up.
Wood veneer deck finish
Like a lot of this build, this was unplanned really and I hadn’t decided how to finish the top of the deck. But I figured it would be good to try and do veneer and see how it goes. Loved THE ACOUSTIC build a while back, so figured why not? AliExpress veneer. I had the resin and vac bag stuff already.
Other stuff to work on:
Need to ride it properly and get some testing done! Have had a couple short cruises only.
Grip is clear tape, maybe frit one day
BNM1 angle indexing options are too few, motors too low, or too high (either risk hitting ground or rub deck on heavy lean). Need to redrill the plates for a mid point or (most probably) change to a cal2 50 degree plate up front to try and fix the issue (could use the turn as well).
Could get the aluminium wheelbase extension plates remade accurately (my hacksaw and battery drill job is a bit janky).
@DRI - likewise for the robo and gps
@Boardnamics - cheers for the steel hangers and gears Kevin love the free roll
@surfnacho - for the cool offset heatsinks!
@Haughbag - great work on the Sunnko!
Cheers dudes, looking forward to 2022!