BTTF Flux Capacitor replica

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.


Well-Known Member
I got the box thanks from a US friend long ago, maybe last year, I've been wanting to make a nice replica of that thing for my basement stair case and put it next to the electrical panel, breakers and breakout box to keep the "props that work" kinda look.
Since we will be staying home for a while with Covid19, I got all my ducks in a row, purchased more primer and 7031 RAL (battleship grey) and that's the nice opportunity to make some CAD for the whole project since I'm learning inventor and leave Solidworks for good (license cost, we get low budget for software and have access to most of autodesk SW for free being an education entity at the Institute).

Basics :
- I've use those 3 main sites detailing parts found and (some) history :
Like many people, this is not going in a DMC and I'm willing to make a few compromise on some of the parts used for the replica. Most obviously, the high-voltage relays are out of range and since I want to do CAD, I'll 3D print them, and use plastic sample tubes for the glass parts.

I got spark plug covers and had another friend ship me some mc master carr gasket/seam for the window which source from myfluxcapacitor seemed on par. The acrylic window I'll cut myself (laser on order but not there yet).
The cable I got is probably too thin, but it was free (from the day job). It's some audio / MIDI cable by Gotham Audio (switzerland) from the 80's, color looked decent and I had at least 50m in the office, I'll see what's the overall look when I install everything.

Electronic speaking, I'll just a put a CFX (saber sound board) inside and probably use ledtrip lighting instead of individual ones, the write a couple of effects (I'll have to look to the move sequences again). From what I've read, the scrolling isn't accelerating, only the core getting brighter (as well as the inside of the box with addition lighting). I might add some 7 segments with ticking sounds and music, since the CFX can do all that in a stamp size. Finally, I haven't decided what do do for the triggering, possibly IR or just a switch to play thru different modes. That will be installed in the stair case of the basement, but I'm targeting a wall-removable unit so that I can take it in the car for geek purposes (even if it's not a DMC).


I didn't see any accurate dimensions in the detailed builds here or online and most people confessing eyeballing everything so... I'm studying dimensions based on a still picture from the movie and mapping them to physical dimensions in Adobe Illustrator. My main concern is the size of the window : the other parts have dimensions that are easy to obtain with 1-2mm accuracy or less so their placement in the box is constrained by geometry and size. However, what you will see from the inside and the overall look and "accuracy" of it really depends on what's revealed by the window.

I also started modeling the relay base (glass parts to be replicated with test tubes, made out of plastic, and some brass parts). Labels I found templates shared here by RPF members, I have to see if I can print them on silver paper or something, maybe print on mylar or acetate sticker sheets that go in the laser printer, then glue them on silver / alu foil. That's the fun part of finding a manufacturing process for the replica, I love that moment :)


Templates to see what I'm doing

First glance and attempt at Inventor. Replicated the small seam around the relay base, since it's made of sheet metal


and printed results, I'm still tuning the basics of the 3D printer, testing the HIPS material, nice finish, not as good as ABS but probably works as good for priming and painting


The next step is really taking the time to model the whole scene and box in Inventor using the Stahlin box 3D CAD (dxf), it's really a good exercise even if it will be really tedious. That's the only way to cut the front window at the right size, cause I'm not really satisfied of any of the measurements I've seen online

I figured out a lot of things, using expected geometric properties, alignments, and trying to fit to some inches + pure fractions reduction, using only the still shot from the movie


Then I tackled modelling more parts and deal with assembly of parts in Autodesk Inventor, tedious process since I'm a CAD noob
I'm not after rendero-vomits, but need to model the whole thing to see how we "see" thru the window and ensure it's correct before I cut the box, hence figuring out the cut size and placement, very important.

wire pin modelling...


solenoid assembly

and the box is coming along slowly


ah last purchase of the day : a 1/2" embossing label maker because the one I saved from my childhood is only a 3/8" one, ebay to the rescue :)
Last edited:

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.


Well-Known Member
Modeled the whole box with gasket (from the master carr profile, slightly adapted to keep it simple) and even the transparent window, then assembled everything with constraints, which was new to me (I've essentially worked with single parts so far).

Tested my 3D print finishing resin that I purchased ages ago (smooth-on XTC 3D), it still looks ok, the thixotropy is indeed perfect, I warmed it up with the heat gun (about 100°C) to remove bubbles and I let it soak in the 3D printed mesh from there, we'll see what happens. Claims to fill 90% of the gaps, so slight sanding afterward, and grey automotive primer before paint and maybe gold rubnBuff.



I got my plastic tubes yesterday, time to mockup the details of the solenoids, there's a W type of stand and the glass tube support, so I'll get back to CAD after priming my bases. Still missing the 3/4" acrylic balls for making the glass tube joints, hope that will be sent to me quick


Sr Member
I'm curious about your results with the XTC coating.

I found it somewhat rubbery, which made it odd to sand. Also I wasn't too thrilled with the result: I went from a stair-stepped part to a blobby part.

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.


Well-Known Member
I found it somewhat rubbery, which made it odd to sand. Also I wasn't too thrilled with the result: I went from a stair-stepped part to a blobby part.

It cured rock solid, but I use a 1/10 gram scale and respected the 100:42 proportion by mass.
Still, it remains epoxy resin, so it doesn't sand like primer or 2 part putty (which is usually polyester ?) and rather like devcon or JB weld. I just gave it a rough sanding (240) to even the faces and the unavoidable elephant feet at the bottom of the base, and coated with grey primer, looks awesome. Filling the gaps with only primer would have taken probably 5 or 6 spraying + sanding. Here's, I'll be at the finish phase after 3 coats (1 thick and 2 thins)


Well-Known Member
This looks nice - a very good start! Thank you for quoting my blog page as a reference - I take that as a compliment :) . Obviously, in terms of accuracy, your project is much more ambitious than mine. And you are absolutely right: From time to time (pun intended) you have to take it into your car. Nothing beats driving during the evening/night with the flux capacitor operating on the back seat - makes me forget that I'm driving an ugly Toyota.


Well-Known Member
Paint job went ok, today I'm working on a companion for this Flux Capacitor : a speedometer that I'd like to animate along with the flux cap. sequence (getting brighter, travel in time, yada yada).
I want to have some sounds for this, and what immediately came to mind is a ticking sound when a digit changes, a bit like in the Marvel Intro with the sound of the flipping pages...

So I went to record my own flip / tick sound with playing cards dampened with plastic wrap...

I've also wired the CFX I'll use for the project to some 7 segment displays to start working on the animation

Just received the actual parts for the Delorean 88 MPH Speedometer Replica. I got a GPS module for this thing but I don't know if I go GPS or use a OBD2 interface for it because it's not permanently installed into it. It will have a live mode animating the flux capacitor in a remote way, and a display action with a switch that will trigger the sequence, accelerating to 88 mph + light blitzkrieg stuff.


And here are my painted bases. 3/4" acrylic balls are on their way, got shipping confirmation yay !


Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.


Well-Known Member
Thanks ! I kept going with CAD today and got to put everything in place with mechanical constraints and fasteners. It's nice on the technical point of view however, I think my measurements are off and the view thru the windows don't really work I think.
Here's a picture from Rook's Castle, I'm not sure if it's from the original prop (?)

You can see the solenoids standoff is almost touching on the right upper side. In the upper left corner, the standoff was moved, maybe it was touching ? There seems to have quite a bit of space between the bottom solenoid standoff and the border of the box. Visually the proportions of the parts look correct but I don't know...
If there's someone experimented with those Flux capacitor's replica here, I'm all ear.

Some progress as I'm getting slightly better to CAD and constraints.

However I'm sure it doesn't looks "right" based on what the window reveals, hard to tell without good ref pics, I have the feeling that it's not right, checking on other high end replicas. The window cut and border is probably too large. I have to model the Dymo labels and stickers to see what I'm doing


Well-Known Member
Updated window cut and created models for dymo labels to help scaling. Much better. Thoughts ?


compare with bob's version, proportions look better, but still not sure of solenoid placement
Last edited:


Well-Known Member
Well, my solenoid placements and angles were wrong the whole time because I missed the 130° thing and mapped to the diagonals instead. I stand corrected... Looks better to me



New Member
The work you're doing here is incredible. I've been asked to sculpt a Doc Brown mini bust and want to add the FC as the base, so all this insight gives me more info that i'll need

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.


Well-Known Member
it's been a busy week, now that the coffee table is finished, I've put more work on the flux capacitor.

I reworked the CAD design a little based on the first templates I cut with the laser using cardboard from amazon boxes and adjusted the window size and cut accordingly.


I decided to go with ledstrips under the solenoid tubes and acrylic angle blocks in order to better emulate the cylon effect of the transition between one light to the next. Original prop had 3 or 4 lights, with incandescent bulbs, and like on pinballs, you get PoV with the filament staying hot. RGB ledstrip will also allow for adjusting color temperature to a better warm white and do some unicorn fart rainbow silly programs as well while playing the hypno toad.

I had some SK6812 skinny ledstrips I won't be using for sabers and I've been willing to use as much of what I have in the shop (fridge props FTW), so I wired 9 pixels under each blocks, all in parallel with their own data line 330 ohm resistor, I don't need to address them separately from one branch to the other.

Then to the solenoids and tubes, quite some work. Too bad I don't own any acrylic glue, I used CA glue and got (expected) whitening. It looks "ok" like a faded glass and brings some vintage look.
I started with the height caliper and marked a reference length for all my tubes with the carbide end


then I used the mill to square up the acrylic spheres, first pass random (after centering the end mill) then that face to the static jaw of the wise for proper square reference

cleaned with 600 grit

then to the tubes with the favorite machinist moment, the parting tool or **** it up at the last second. Handy to have a few tubes left, I broke 3. But they are called TEST TUBES anyway :-D


got the laser with test material including neon pink acrylic, 3mm, stacked up 3 pieces to get close to 3/8" and have a fit test, not too bad. Tube supported printed in ivory ABS, really neat, 2 coats of primer on top of that + 2 coats of paint and good to go


First template cut out of cardboard for the internal base board, to see how it looks. Fits nicely and I'm glad I modeled everything


Tubes ending with brass accents, to the lathe again


Tube's internal rod = TIG aluminum rod

Then people started to say I'm making meth pipes...

The base board I laser cut on ABS. Since it doesn't cut so well and tends to melt, I only cut the contour and only etched pilot holes / marks for all the holes which I drilled with the drill press

Started to look legit


Well-Known Member
Then I tested the look of the window, gasket placement and acrylic window clearance. That revealed some measurement / size issues for the top and bottom, not enough space for fitting the dymo labels => reworked the CAD


Better fit, clearance includes the box cover radius, about 5mm

Then hot glued the spark plug connectors and wires, and took the box to the paint booth after I cut the window (leap of faith cut !!)
The internal base board received 1 coat of plastic etching primer, 2 coats of Molotov's satin black and 2 coats of Besa flat black to provide a slightly-grainy texture and cover the marks on the plastic
and I finally got some use of my bench cookies !



Placed the labels on the solenoids and made the small metal rod attachments / tube holders. Didn't have the proper gauge, some of my stuff stayed at the lab in paris...




Well-Known Member
Then I started wiring things up.
I decided to go with a 18650 li-ion cell and a recharge port. The main switch, I pondered a long time, I have to get an easy access to the switch when it's installed in my stair case, so not behind. I had those missile guarded switches that I initially purchased to make some "passive aggressive triggering" machines and figured it would preserve a sci-fi look since my replica is no where close to screen accurate....

- Speaker will be hidden inside the top 90° heat exhaust with a good resonant chamber.
- I'll be installing some IR remote to configure the props operating modes, that saves me from having any dip switches or coding wheels to set, and it all can be done in the car when I drive
- Speedometer attachment will work both as a remote or as a slave : driving in GPS mode will have the real 88 MPH (or km/h) trigger the capacitor sequence OR the IR remote will initiate a speed increase, reflected on the slave speedometer then reach 88 and fire in the hole.
- Both units will communicate by bluetooth
- Runs with a Plecter Labs CFX :)
- the 4 corner leds (5mm warm white) and the central cluster are driven in PWM by the CFX onboard power driver L1
- I'm also wiring the ledstrip output LS2 for an additionnal ledstrip hidden in the cover for additional fx once all the rest is done



Base board wiring (ledstrips covered with felt tape, like in the falcon, to avoid light leaks... and keep the 1.21 gigawatts inside !)

Current look with window in place and proper focal view (using the portrait lens of my phone, reproduces pretty well the FoV I have IRL

Will make better pictures with proper focal point behind the windows when I get the lighting to work. Till then, I just tested the ledstrip with the usual unicorns


Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.