BTTF Hoverboard replica (WIP)

[erv]

Bottom line : I wanted to have some colors added in the staircase that leads to the basement, it's still WIP with a death star hallway wall panels theme, so mostly grey and white. I've added the flux capacitor there and as I was progressing toward my prop list that I wanted to build for display, I realized I could build a hoverboard that will pimp the staircase up.

Well, it opened a new can of worms (and a double can of work) as building a proper replica of this is more than just plywood and paint. As usual, based on materials I have and the money I've already used during confinement to propel the shop equipment and gear, I don't want this to end as a $2000 build so it won't be totally screen accurate.

I started by harvesting the wood planks I had left, birch plywood left over but not the right width and not the right thickness. So, woodglue and dowel to the rescue, and thank you DiResta + Bob (ILMS), learned so much with those guys YT channels.

It's very close in size compared to Bob Gale's ref pictures, just had to scrap 5 mm on the width because of the wood I had. I decided to add strengthening screws on the flange part since I want to be able to ride it (more details on this later) and I also fibered it, top and bottom at the junction. Rock solid and ready for back-flips !

To complete thickness and get close to the real thing, I covered the wood with spray adhesive and hot-bent cintra I had (almost) in the right quantity

It's been fun to play with the router to make the side angle cuts
Vector graphics printed for just a glance of the color distribution. Velcro ordered, paint as well. Will not go for the printed decals and that file I sourced is really not close to anything (even though it's been probably a lot of work to draw). I'm going to make my own logos and graphics in illustrator from Bob Gale's ref pictures (original props vs. mattel). I don't have the "right" lenticular material but something good enough from IKEA anti-slip drawer film (the shop is almost 100% IKEA kitchen stuff).

Now, there's obviously more CAD to work on and 3D printed parts to make for the bottom, but the immediate next step is priming the board with automotive, 2 part primer (polyester). I'm anxious about using the spray gun cause that's something I don't master as all and I don't know how my new (very small) paint booth will deal with the fumes, as it's not the same pressure than a spray can. But great opportunity to learn new things.

 

[Mechanized]

If the flux capacitor you built is any indication, this is going to be good

 

[thegnome]

That looks so cool!

 

[erv]

A lot of work went into this and a lot of fail too. Mostly the lenticular film I've used with the mantra "it's close enough to the real one plus I have it" lead to have the film not tacking well to any surface, whatever the glue I've used (despite I did test before, on the same wood + paint + clear coat surface, to be sure). It's due to the large surface of film and it's nature to tend roll back. I used the heat gun to flatten it, but still, areas won't lay flat and will resist to the gluing process.
On top of that, the lenticular effect is obtained by flipping it, so the lenses / bubbles are on the board side, and the other side is flat and rubbery. As a result, the contact points between the film and the board are on the half sphere top points of the bubble, hence VERY LOW contact surface overall (would be totally different if the glue was on the other side).
Of course, you can't just drench the surface with glue, or it will fit the gaps between the bubbles and you totally lose the lenticular effect. So, yeah, it's hard, mostly failed but I'm not complaining (my life sums up as trying hard things, with moderate success).

I started by coating the board sandwich with 2 part primer and the spray gun. I have bad history with spray gun combined with the fact I didn't have the proper infrastructure to use it. I did the priming in my little paint booth, next layers, paint and clear coat outside on a wood pallet, as I would turn around. I got better with the thinner dosing and the spraying overall pretty happy. Of course, all my primer hardeners were FUBAR, I used other chemical, primer cured, all good (fukken saved). Ordered more stuff, for now I'm using what I have on the shelves.
The different nature of material between the sintra and the wood makes it hard to stabilize. After several coats of primer, I went back and forth with 2 part putty and CA glue to seal seams.

Paint is less neon that it looks, I called it psycho bitch pink. I have neon paint ordered for finishing. It brings the nice purple / pinkish shade seen thru the lenticular film (clear). Accurate film was pink already, reason why I had to sub coat with paint, and stabilize the whole board.

Then clear coat, I had a LOT of PU clear (2 part) for furniture, and it was still alive (hardener as well). I also wanted the glue to bite on something hard, not the paint, or it would have lifted it first thing. That was a good idea as I had to pull the film a few times, even after gluing it. PU coat won't ******* move, it's amazing.

with everything hardened, I could start the study of the electric skateboard retrofit since I decided for a prop that work for this POS project
Happy to see I could recess the wheels structure and control board on the rear and it should all fit under the levitation pads / cups. The battery will go in the central bottom piece of the hoverboard. I'll have 2 differents pads, one hollow for the skate use, one filled for display (I might just change the top surface of the pads with neodymium magnets for a quick(er) swap

To make it as flush as possible, I cut the sintra to recess the rubber pads / shock absorber of the wheels, that saves 3mm and creates a bette bolted structure to the wood instead of the sintra (which is way less dense as wood).

Bolted with some tension. I've passed the M5 screws from the top side thru metal wood inserts. Screws will be later glued with JB weld and CA glue so they become like studs.

great scott, I turned a skate board into a skate board... awesome !
Same, screws got recessed below the sintra. Once glued and stud-like, pigmented PU resin on top of that, sanded flush, paint, and another clear coat to hide them. This could have been done formerly before the whole paint job but there was too much unknown about installing the electric skateboard and all. I'm not much concerned about perfect the top side has to be, since the lenticular film will hide any small detail once the studs gets at least covered a little with resin and paint.

First attempt of gluing with splatula-coated UHU POR glue (depron safe). Major fail. Clear coat didn't move even when I removed the film "wax depilation style". Glue dry rubbed with fabric to aggregate it first, then remaining glue went off with Essence F.

Attempt #2 with 3M "77" spray glue, better but still not holding everything in place. I further tried to seal the edges with PU clear (syringe applied then sprayed) but it lifted and messed it up (again). Ended up with CA glue to stabilize the seam and of course it penetrated the lenticular pattern and ruined the edges.

To save this fuggly-fumble design (tm) I'm going to use some duct tape over the seams and edges and re prime and repaint, we will see if it stable enough to be usable. Gave a try to the vinyl I cut and printed to have an overview, pink duct tape I had ordered to eventually use instead of vinyl for the bottom side. Vinyl printed on the laser printer came out great, and pretty happy of my vector work from Bob Gales pictures (computers have Ctrl-Z, thanks, life hasn't)
So, back to the spray gun to fix this !

 

[erv]

Not much "visible" progress this week since I've been in house maintenance outside (paint + oiling wood surfaces, pool, wall tops, shed) and added a primary filter to the paint booth...

I coated the the sides on which I taped the lenticular film with 2 part primer, then sanded, painted and sealed with 2K two part clear, since I had a can I just snapped for my outatime license plate, now the film isn't moving anymore. The bond isn't super strong but at least it should bubble like before especially on the sides

the sides are now deep green which is the infamous color NORI (anagram of NOIR = black, ordered by mistake for obvious reasons). Great paint though, keeps building up the sides.

Printed some of my 3D pads in strong ABS (zortrax ULTRA-T) to have a look, test fit the battery. I used a blueprint but since my board is slightly off scale, I'll have to shrink everything down a little to fit the length. I'm currently printing a new set, we'll see in 21 hrs

I'm now waiting for my neon pink for the sides, automotive paint, I just received the notice that my order is being prepared, can't wait to put the final coats on this, seal, and install velcro and such

to be continued...

 

[erv]

Fluo pink paint was delivered. More problems along the way as the border structure remains really flimsy, so couple of primer coats and a few spots to bondo. Squid marks remain but only if you put your nose on it, I overall like the result despite of the cumulated fail. Both my daugthers went to me with an (elementary grade) teacher look and said how awesome it turned out. Don't be afraid of perfection, you'll never reach it (S. Dali). I sealed the pink with 2 coats of shinny clear (medium gloss), made the color more uniform, but slightly more red, looks fine on camera and from a distance, neon pink result so depends on lighting. Very satisfying to finally apply the stickers and velcro. Bottom elements fitting test, still needs some work, adjusted dimensions a little and printed in PLA this time, I need to trim the pad to fit the rear skateboard element now that the pad is a little smaller in diameter, then I'll go for the final assembly and painting of the bottom greeblies Top side finished, I might redo the MATTEL stickers as they are now a little too big with the width reduction and the overall scale of the board, but they fitted and I had them printed and cut, so I just placed them, feels cherry on cake

 

[MAKE BELIEVE]

Great job !

 

[erv]

finally finished. Some hard time with the central coupler (purple / violet part hiding the battery) as I didn't want to reprint after painting it with ****** art clear coat and paint that isn't even compatible with a double coat of itself... Primed many times, sanded, heavy coat of paint, still not hard cured, but it's stuck in place now, with double sided foam tape, pictures are taken, end of the journey pheeww

I made de top of the levitation plates in MDF and cut 2 versions, with skate parts installed and hero parts, magnetic attachments, quite easy to swap. I initially recessed the skate drive units but finally cut a MDF space to raised them of 3mm to have enough clearance, it's still not enough to steer, so you can't really ride it and turn, it's easy to have the wheel touch the levitation pad... tough decisions, if I had to make another one, I would definitely make a deep cut in the pad and have full hero pads and separate skate pads, but it's okay, it was a fun project and it "works", not a static prop

 

[erv]

]I opted for the ref picture on which the "red" couplers are rather rust / orange(ish), I liked the color and found a decent shade matching this in the Molotov rattle can colors
I'm also very happy with the central purple box, perfectly hiding the battery and holding an almost invisible recharge port.

There you can see the electronics of the motor controller (ESC). I rewired the stock PLI using 3mm LEDs and chromed bezels for a retro-futuristic look on the side of the levitation pad.

with wheels and motor installed, levitation pads covers made our of MDF, prototyped in laser cut cardboard first. Chrome paint.
I also added a 2 layer, bicolor vinyl sticker I cut on the silhouette cameo, a simple redux of the mattel logo of the top side of the hoverboard

More glam shots.... charging

Battery PLI, activation switch and wireless connectivity (to the remote) LED

Then I finalized the foot strap, pad is 2 layers of 3mm MDF, green vinyl and velcro. With Covid-19 lockdown I didn't have the time to source the pink fur, I have to see if my wife has something in her fabric stock. For now, I did a place holder strap with double sided velcro

Hope you like it. It's been a nightmare of paint job due to the lenticular film gluing, but overall a great opportunity to practice the spray gun, clear coat, illustrator and electronics retrofit, a lot of fun too.
I have a video where I (sort of) ride it, I'll post that once I have a chance to edit it. Disclaimer : major design flaw, I wanted to have it as low profile as possible while preserving the size of the levitation pads. As a result, the wheels easily touch the pads if you try to turn and bend the wheels train. But Technically it works Also I know that the Mattel stickers are oversized, I already printed them and cut their profiles with the vinyl cutter, that was before the surface shrunk a little when I thickened the pink border to hide the lenticular film mess. I'll reprint them at some point.
Finally, I don't know if the 2 sets of pink velcro (front and rear) are all parallel together, I tried my best to extrapolate, I though it could be, or, the opposite, that with such a zig-zag design, there was no reason to have a lines parallel, while the prop store picture seems to show they are. Don't know. Anyhow, it's just another attempt with fugly-design.com result and screen accuracy is probably the last of my concern lol. Still, that's probably good enough to decorate the stair case !
here's a quick mockup side by side with bob gale's pictures. Not "accurate" I suppose, but not to shabby, right ?

 

[Aditrap]

Wow! Just rewatched the film last night and was looking through a few of these and I love how this one turned out. Nice job!

 

[justy]

I've wanted to make a working one like this for soooo long! You have re-inspired me! Thank you!

 

[erv]

I've wanted to make a working one like this for soooo long! You have re-inspired me! Thank you!

cheers !!! Glad to see more "working" hoverboards coming to life !

 

[knightedbylight]

Can we see more photos of this? or video of it rolling? this is amazing.