Dematerialiser's Dematerialisation Circuit

[Dematerialiser]

« Reply #42 on Jan 31, 2007, 3:43pm »

Crispin wrote:  went back to the place where I found the last lot of 2" grinding wheels, but they didn't have any smaller ones.

Thanks for looking again Crispin!    I tried to contact Faithful, but they pointed me towards their catalogue - and the grinding wheels aren't even in it! Makes me wonder whether those shop assistants were right when they told me that they were being phased out because they're not as safe (for grinding) as the grinding discs with the holes through the middle. But who knows.

But, back to the diameter, I've started to wonder whether the whole thing will look oversized if it's "2 diameter discs instead of the 1.5". The second thing that concerned me was the general consitution of these grinding wheels as/after you've drilled holes into them - perhaps they'd shatter or crack (I have no idea as I've never tried to drill through a grinding wheel..!) and then there's those smaller holes to drill into it for the wires and the screws in the top of each disc; All of this drilling makes me wonder whether the grinding wheels will survive intact.. Or perhaps it'll take too many blunted drill bits to be practical..?

So, as we're all after the texture of a grinding disc, I have been wondering about making discs out of wood and then, using spray adhesive, coat them in the grain from a smashed grinding wheel. Just an idea at the moment, but perhaps two careful coats would produce something that looks just as good.

Oh, and a quick update on my idea to put a switch into each disc - the LED-lit switch I bought was a sealed unit and couldn't be dismantled without breaking it completely. Back to the drawing board on that one! I have another switch in mind though..

Before this d**n headcold got me, I was also looking into several suppliers of the acrylic, but still can't find the green in the sizes I'm looking for.
On the upside, I did order a small bandsaw which arrived today, which is perfect for doing straight cuts through metal and plastics. 

I'm planning to use that atom model I bought as 'pins' to hold the clear acrylic rods at the right angles (by drilling holes for the atom 'legs' into the end of each rod). 

Oh, one last thing - I did rewatch the Terror of the Autons to make sure we're not looking at the Master's mark2 demat circuit in one of those reference photos.. In that episode there's one scene where you get to see both circuits, and they're both identical as far as I can tell. Even the colour of the core of both circuits looks like a mid-toned silver/light grey, rather than black or dark grey; which makes me think that the reference photo we've been looking at with the darker coloured core (from Day of the Daleks) might have been the result of the prop being damaged and patched up, which might be why it looks a bit lumpy in the middle.., or just refurbished a bit for some other reason. Food for thought anyway. I think I'll go for the silver/light grey core version.

Sorry for the long post! 

cheers
Chris

[Dematerialiser]

« Reply #51 on Feb 3, 2007, 7:41pm »

I had a chat with my father-in-law today, as he's got plenty of experience with materials too.

So, back to the idea of coating a disc in some kind of powder coating - I found out that the abrasive material that they actually use within these wheels/mounted points is 'carborundum', and like sandpaper, it comes in various 'grit' sizes. I've only searched briefly for the stuff, but it should be possible to buy a bag of the stuff and use come kind of ahdesive cement to coat a 1.5" plastic/wooden disc in it. The big bonus would be that it would have just the same texture and finish as the elusive grinding wheels/mounted points we're all looking for, but without all of the size and drillability issues. Plus of course we could then go for the 1.5" diameter discs, which (I think..) are the right size for the prop.
When/if I find a (UK) supplier I'll let you know, by the look of it it's cheap

cheers
Chris

[Dematerialiser]

« Reply #53 on Feb 5, 2007, 2:39pm »

I've been spending some time revisiting my measurements, looking at the photo's etc..
So far, I'm working from the guesstimates that:

- the discs are about 1.5" (I'm going for a round 40mm..) in diameter, and around 10mm thick
- the small green 'cap' on the top of each disc is probably 10mm or so in diameter, I'm going for 12mm because it's the diameter of the button on the switch I'm planning to use.
- the large green 'washer' underneath each disc needs to be 20mm or 22mm in diameter
- the clear acrylic rods I now think are about 12mm in diameter, instead of the 15mm I'd previously thought. I've only just come to this conclusion this morning, looking again at the photos..

As for the lengths of the rods, I'm going to worry about that when the rods arrive, once I have a chance to test-assemble a few pieces.

By the way, re: the grey discs, I've also orderered some 40mm grey PVC rod (from ebay) which I'm planning to cut into 'slices' of around 10mm. The reason I've gone with grey is because it's a good base colour for the grit I've found to coat them with. Also, the PVC is opaque instead of translucent/transparent (as most acrylic rod is), which means I won't get any light bleeding through it where my grit coating might be a bit thin..

Also, I've managed to find some of that 'Carborundum' grit/powder that I mentioned earlier, by searching for it's other name: 'Silicon Carbide'. I've found that, like sandpaper, it's graded by coarseness. I've ordered some 20 grit and 80 grit to see what it's like. The great news is that I spoke to the retailer and confirmed that it's dark grey in colour, and has those 'sparkly' particles in it - just like the grinding wheels that they make from it. Here's a link to the UK supplier I've used: http://www.ukge.co.uk/UK/prodtype.asp?PT_ID=384

The plan is to bandsaw the PVC into discs, drill the necessary holes for the led/switch/battery and rod, suspend the disc and spray with adhesive (I've found some spray contact adhesive that sticks stone, wood, metal, and PVC..) and then coat the the grit, probably a couple of times over.

Mind you, this is all just a plan I've dreamt up - the reality will probably kick me in the teeth when it comes to it

cheers
Chris

[Dematerialiser]

« Reply #57 on Feb 9, 2007, 10:06pm »

Measurements sound ok to me - but don't take my word for it, I'm still working it all out based on guesstimates!
Personally, I don't think the centre of the circuit is a ball - I actually don't think that any of the circuit props had shapes in the middle, or 'bumps' on the coloured portion of the legs - but that's just my thoughts on it. I think that, when you use studio lighting on such an interesting shape you get some very misleading shadows!

cheers
Chris

[Dematerialiser]

« Reply #61 on Feb 10, 2007, 4:35pm »

Before I decided to go for 1.5", I never actually got around to positioning the wheels to see how they look in the right configuration.
One thing's for sure, it's almost harder to find decent reference photos of the demat circuit than it is to build one!

Scans from the annual look really valuable from a research point of view.

cheers
Chris

[Dematerialiser]

« Reply #65 on Feb 13, 2007, 8:40am »

The more references we can get the better. That said, I don't think we've got more than a couple of pictures that actually look like the same prop! (for instance, the wiring on those '73 annual scans actually looks white, instead of the copper and orange we can see on other pictures. Maybe they used a prototype version of the prop for rehearsals/production stills or perhaps the original prop was mended/changed for the actual shoot, or perhaps it's a trick of the light (again.. )

I got the right stills there - they're the best ones I can find on my fuzzy copy of that episode (if anyone else has a better quality version maybe they could do some screen grabs?). As for that wiring - I think there are some extra orange wires there (but the extra wires aren't on the Day of the Daleks version of the prop).

cheers,
Chris

[Dematerialiser]

« Reply #67 on Feb 14, 2007, 7:54pm »

I agree about the wires probably being the most fragile part - they seem to change a lot - they probably got broken (especially when you see how Jon Pertwee handles the thing at times..!  )  or simply fell out and the prop dept never bothered to replace them.
By the time we get to Day of the Daleks there's only bare wires left!

The big difficulty is which version to go for. The image below is a production still from Terror of the Autons; and I can't see the white insulation on the wires (actually, there might be the suggestion of some on the wires on the far right.. but it could just be lighting/flare)


The reference photo's we have from the police car scene are of the Master's #2 circuit that the Doctor steals from the other Tardis, so *if* it's true that the two props had different coloured wiring, I think I'm going to go for the one in the production still above, as it may well be the Doctor's #1 circuit.
Another thing I noticed from this episode is that there's one scene where both circuits are in view. One of the props clearly doesn't have any screws on at least three of the grey discs, and one of the grey discs doesn't even appear to have a green centrepiece.
Here's some stills:


Perhaps the prop wasn't quite finished in time for the scene (but was finished by the time they filmed the police car scene). It's also the one of the two props with really obvious white wires on it, so perhaps this supports the idea that the two props had fairly big cosmetic differences, with the Doctor's #1 circuit being designed as the 'hero' prop, and being more detailed and 'finished'

This is all just guesswork tho' (but fun, and a challenge)   
Anyone got some different ideas on it? I'm really puzzling over the beads - which colours, and where they're placed in relation to the different discs..

cheers
Chris

[greatwazoo42]

It's going to be great to see one of these fan built.  Keep up the good work!

[Dematerialiser]

« Reply #46 on Jan 31, 2007, 10:06pm »

It might well. Another alternative might be to dip an MDF disk in medium fine sand after spraying it with adhesive or perhaps even primer paint. A layer of primer and spray paint over the top would finish the job. One of these days I'll give this a go. The nice thing about the grinding wheels is that they'd give the prop some weight, which it would not otherwise have. I'd thought of using disk-shaped magnets, but haven't found any in a good size.

Exactly that has been on my "to do" list for years...  I've also been planning an LED light chase built into the circuit which operates when it's installed. I don't think it was ever illuminated on screen, but it would be such a nice thing to do. Ah, one day...

Crispin

[Dematerialiser]

« Reply #62 on Feb 10, 2007, 5:13pm »

I've just got more screen-captures from the episode, but all of them aren't as good for detail as the one(s) already posted in this thread - except for one, which is in that scene in the police car.



Based on this, I don't think that the middle of the circuit has a ball shape in the centre. Looking again, I think that it's white (or at least pale-grey-white or perhaps matt silver) in colour.
There does appear to be some tapering of the white sections so that they get wider towards the middle/core, as you mentioned (but to what degree is debatable, just look at the difference between each screen-grab!  )
I think I'm going to go with white tube and see what I can do with it.

cheers
Chris

[galacticprobe]

I know this topic has been quiet for some time, but I just came across this photo on the LJ Doctor Who Cosplay Community. Someone there threw together a Demat Circuit and asking how everyone thought it looked. Someone suggested posting photos of the original prop for comparison, so I replied and directed them here, to this thread. And someone else (who goes by the username "misterandersen", to give credit) posted this photo, which we don't have in the thread (but we do now):



If your browser shrinks this down to fit the screen, open the image in a new tab or window to see it full size. It's a screen grab from 'Day of the Daleks'.

It almost looks like that bit of green below the discs is clear, and extends around the clear part that connects the disc to the silver bits of the hub. It also looks like some discs have more wiry bits connecting them together than other discs do. I still can't make out what that green cap on top of the disc is.

If only they would digitally remaster this story for the DVD (or Blue Ray) then we could get a better resolution image of this and maybe gain more knowledge of what the unknown bits are and how it's all put together.

Dino.