Back to the Future Plutonium Core

With so many posts centered on Back to the Future I have always felt right at home in this forum as it is my all time favorite movie. A Plutonium Case build thread really got me into the idea of building a Plutonium case and stocking it full of cores. I found a used transit case to act as a donor and started work. Then I learned that Christopher Lloyd was going to be in town and I frantically tried to figure out how to finish the case quickly so that I could get it autographed. Alas it was not to be, I just didn't have enough time to get it done (if only I had more time.. ). Then the answer became clear, build something smaller.

A core was the next logical choice because I needed to figure out how to build them anyway and it would be much easier to carry into a Con.

I started with Sketchup to figure out all the dimensions and pieces needed and created the cut away image below to show the assembly. I would settle with being as screen accurate as possible but not to the extent where the prop didn't actually work. I got the over all dimensions from posts on this forum as well as a Screen Used page then bought a bunch of common sized tubing to figure out the rest.



The two things I wanted my core to do was hold water and hold and release the inner red core. To hold water it would need to be water tight but also have some way of filling and draining the water. To hold and release the inner red core the bottom will need to rotate to allow the inner core to drop out through a hole in the bottom. From the CAD image you can see there are two bottoms to the core, the most outer one will rotate which means I will need to create a pivot point for it to rotate about. Can anyone think of another way of doing this? I have seen photos of a version with the hole in the bottom but it appears really big, so big that there wouldn't be any material in the center to put a pivot (See picture below from http://www.bttfmuseum.com) Also note in the CAD file how the inner core can not come out the top. The inner core 'sleeve' does not go through the top but it does go through the bottom. This will stop the inner core from falling out the top as the inner core spacers won't fit through.



So my bottom hole is smaller and the inner tube hugs the outside wall in order to have the room for the pivot.

Parts ready to go.



Then sanding, sanding and more sanding.

Then more sanding.



Then a lot of polishing, lots and lots. I forgot to take a picture though, because polishing. (On the next one I will)

Finally the test fit and I am ready to go!



More to follow.

Brilliant, I tried building this a few years ago, but is had no resources, now you have inspired me

Excellent! I will get an update posted today to keep you interested

Cleaned up and glued the canister fits together nice and tight.



In the next shot you can see my solution for filling the canister with water (or perhaps mineral oil?). I drilled a hole in the bottom plate and tapped it to accept a shallow set screw. A little bit of Teflon tape on the threads and it is good to go.



The previous picture also shows something that I have yet to work out. The 'glue' or solvent was recommended by my local plastics supply as the one to use if I wanted it water tight. The name is escaping me at the moment but it was gel like and when dry is basically solid acrylic. This means it is easy to clean up with sanding and polishing. However.. It appears to be cracking my bottom and top plates (those thin lines radiating inward from the edge). The top and bottom are not overly tight fitting, just snug, and I have no reason to believe they are forming the little cracks because of pressure. I called my supplier and they had never heard of cracking forming like that using the glue.. Any ideas? On my next canister I will try silicon and see how that works.

To quickly finish the core I used a red Sharpie and was quite happy that you couldn't really tell. It look horrible until you coloured all the way around the rod and then the stroke marks became really hard to see. I have since bought transparent paint to use instead. I was also out of yellow ink so the label was white with red lettering, a highlighter provided the background colour (again something that will be fixed on the next version).



-Big thanks to Roland for uploading the label to the forum

I am still deciding if I want to make the spacers red as well... Almost all versions I have seen made have red spacers but where Doc loads the Plutonium they look clear :


(Look at the left edge overhanging the inner core, I believe the middle looks red because you are seeing the colour through it and the edge is clear(er) because there is no red directly behind)
It is even more apparent as a video. I like the idea of the spacers being clear because a solid smooth rod of Plutonium looks nicer to me . If it was real.. the spacers are around the outside of the rod only to hold it in the middle of the inner tube. Sacrilege?

Next up - results from the Con.

It was my first Con and hopefully not my last! Meeting Doc, I mean Mr Llyod, was fantastic. He was soft spoken, charming and even taller then I expected It is awesome when a character you have idolized pretty much your entire life is played by a actor who is just as cool in real life.

It was my intent to take a picture of Mr Llyod signing my prop but in the end I just wanted to have a quick chat and take it in. I was also hoping he might say something about the canister but he ended up just really concentrating on *how* to sign it (being a curved surface).



Now I can't bring myself to put any water in it because I'm afraid of messing up the signature :facepalm



So if anyone has any remarks on the build (especially on some of the points I brought up in the previous posts) that would be great! I want to start on the next version and try to get a better build.

Really cool! I hope I'll meet him some day, would be great...

Wow, great build! Looks fantastic. I wish I had the skills and the machines to work with materials like those. I'm glad that I could help with the stickers.

Roland said:

Wow, great build! Looks fantastic. I wish I had the skills and the machines to work with materials like those. I'm glad that I could help with the stickers.

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Do you have a core in your collection?

Omni said:

Do you have a core in your collection?

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Unfortunately no. I'm still waiting for someone producing and selling it.

VERSION 2

It is time for a version 2 of this build to take care of some things I didn't get sorted out the first time around. I want to make enough of these to fill a case, and then some, so please lay on the feedback so this will be the best version I can muster! Here is my current TO DO list.

1. Canister Body

1.1 Solvent used to hold pieces together caused micro cracks in the outer walls, probably isn't water tight. Need to find a good silicon perhaps?

Option 1 'Extreme Repair'
I found some 'Extreme Repair' adhesive that has a silicon like texture. Applying some to two test pieces proved promising as there were no cracks and it dried super clear. I wasn't able to pull the two pieces apart with my hands.



1.2 Work on a better way of aligning the inner tube to be straight and true when assembling

1.3 Is the set screw hole required for filling with water? If I need a hole for a screw to hold the bottom on (so that it can rotate) that hole could be used to fill the canister with water rather then the separate set screw hole..

2. Red Core

2.1 Check for a better way to colour the rod red.

Option 1 Paint
I picked up some red 'Tail light' paint however a small test piece that I painted does not show a nice finish. The small dots of paint from the spray can are quite visible and it doesn't have a nice texture. Perhaps sanding could take of this.. will check tonight.



Option 2 Red Film
The Screen Used description stated that the original used a thin red film to produce the colour. I have no immediate ideas where to get something like this, will check local craft store tonight.

Option 3 Clear red rod
I think the option that would look the best is to use a clear red acrylic rod with a clear piece glued to the top, the label providing a nice way to cover up the seam. Three issues I can see with this idea is finding the right sized rod, the right transparency and cutting and gluing the pieces accurately enough that it appears as a single, solid rod.

Option 4 Continue with red sharpie
I'm still surprised how good the red sharpie looks. Only when you hold it right up to your eyes can you see the strokes. If I were to go with this option I would come up with a better, more uniform way of applying it.

1.2 Seek RPF opinion on colouring the red rod spacers.. yes no?

To be continued...

Curious if there was any progress to your awesome build?

Omni said:

Option 2 Red Film
The Screen Used description stated that the original used a thin red film to produce the colour. I have no immediate ideas where to get something like this, will check local craft store tonight.

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My mom used to own a screen printing company and I remember she always had rolls and rolls of film called Rubylith (red) and Amberlith (amber, obviously) that she used for masking stuff. Maybe something like that?

would red cellophane work? I see that all over the web. Also, lighting "gel". Theres many shades of red for that as well.

I'd be interested in a core or 2 if you're looking for interest.

Omni, I have a huge sheet of red that I use for proton packs lenses, I'd be happy to send some out!!

Hi Omni,
how is going with your latest build ?

If there was ever a run of these,
how much would one cost ?
I would be very interested !!

Can acrylic be dip dyed?

Old project, but since it's been bumped... You can easily get a red stick-on film that's used for tail light lenses. It's basically like window tint but in different colors. I just used some in yellow this weekend. Check eBay, you can get a huge roll for $5 if you don't mind waiting for the slow boat to arrive.

Another option would be theatrical gels. I know for a fact that Rosco makes a very red red.

Finally, Tamiya makes a translucent red for use on polycarbonate RC car bodies that works very well. There's a spray and also jars that you could use to dip it in.

-Rog

I would like to offer an apology for neglecting this post, and also thanks for the replies and interest! I was ... wait for it... moving. Side note - when I first joined the RPF I immediately noticed how that moving seemed to be the most frequent reason for disapearing - it seemed to come up a lot in the classifieds when buyers didn't get their stuff on time Now I've joined the club. One of the main reasons for moving was to finally have a place to build - I am insulating the garage this week!

Annyyy way, I unboxed the Plutonium Core over the Halloween weekend and this last reply has got me all excited about it again - so here we go!

MattgomeryBurns - There haven't been any updates, all my stuff ended up in storage as we tried to sell our house / find a new one, but that can change!

LTsmash1200, FrustratedGamer, Hotshot, whiteee, Rogviler - The film sounds like the stuff that was mentioned on screen used. Thanks for the names and the ideas. Hotshot - Thank you for the generous offer! Is the stuff you have really thin? That is one concern I can think of as the tolerances of the parts are small (especially the spacer rings and the core), though I could just make them bigger if needed. Rogviler - there is a hobby shop close to me that I will check for that paint, that is one idea that I can try immediately!

FrustratedGamer, Soxbrother - I think I could make a few extras to spread the joy! I want to get version 2 buttoned up first though, make sure the problems with the first version are corrected so you would be happy with the prop. I will do up an interest thread at that time.

Thanks again for bringing this back from the dead!

Omni said:

FrustratedGamer, Soxbrother - I think I could make a few extras to spread the joy! I want to get version 2 buttoned up first though, make sure the problems with the first version are corrected so you would be happy with the prop. I will do up an interest thread at that time.

Thanks again for bringing this back from the dead!

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Cool. Can't wait !!

Cant wait to buy a plutonium core over the internet!