Build Log – Part 9
All righty! More work on the engine nacelles – and their internal wiring.
First off I want to sing the praises of that Vallejo surface primer again – it’s been really excellent to work with. Dries extremely smooth, lays flat, and is rather forgiving of when I “overdo” it. I highly recommend it. I used a lot of it on these parts, and will probably need to get another can or two soon.
On to the wiring. I first established how many and what kinds of lights needed using:
LED tape – two strips for each engine, in blue. I thought about going violet (the studio model was actually done up in violet), but I’m aiming to replicate what we saw on-screen, and those are distinctly blue. Each strip is about 20cm long, and I’ll fix them with staggered lighting so I avoid the worst of the “stepped” lights.
Blue LEDs – two, one for each “warp crystal” at the top of each nacelle.
3mm white LEDs – four. Two for each nacelle, one to each side, for use in the Raytheon floodlamp effects.
2mm white “tower” LEDs – four. One for each of the two spotlight ports at the front of each nacelle.
2mm yellow LED – two, one for each thruster section in the fins.
SMD white LEDs – two. One for each of the anticollision strobes on the rear roof of the nacelles.
With the exception of the tapes, each of these LEDs required a resistor…and since I’m aiming to make this a 9-volt setup, a 470 ohm did the job.
A word about resistors and LEDs – when they ship from the factory, the standard for LEDs is to have one leg shorter than the other. That’s the “cathode”, or negatively charged lead. The positive is referred to as the “anode”, and all LEDs are polarized this way…they only work if you connect the correct leads to the correct charge. For bare, unwired LEDs, the resistor attaches to the cathode, the shorter arm.
In my models, I use a lot of “magnet wire,” which is extremely thin (36 gauge or smaller) and insulated using a laquer coating rather than a plastic sheath. Some of it comes colored from the factory in a variety of different shades, and although I do use those sometimes, I tend to stick with this stuff which is really really fine (thinner than a hair), and that stuff doesn’t have color. It’s just bare copper (insulated with laquer). It’s a little fragile and sometimes can be hard to work with, but I find that it fits into the smallest little spaces and doesn’t “spring back” like a lot of other wires can, so the pros outweigh the cons a little for me.
Under normal circumstances, the wires to be connected can be held together and solder applied, which then works both as an electrical connection as well as a “glue” – but with magnet wire, it’s so thin that you just can’t hold it steadily in place and convince solder to stick it properly. It’s also so thin that it doesn’t accept ‘tinning’ like regular wire or cable does.
In my previous logs I’ve mentioned this, but it does bear repeating, so forgive me for my redundancy. To get magnet wire to behave, first you have to get the laquer insulation off the ends. To accomplish this, the best way I have so far (and this is different from before) is to take some 600+ grit sandpaper, fold it in half, and then pull the section of wire you want to strip through the folded paper while applying gentle pressure. Too much and you’ll just break the wire, too little and you won’t pull any laquer off. You’ll figure it out after a few tries. Once you’ve done this a few times, you can then run a hot iron over the cleaned section to burn off any remnant laquer.
I trimmed down the arms and the ends of the resistors to avoid extra-long connectors, and tinned the ends of each.
Since these LEDs have lots of breathing space inside the nacelles, and since I’ll be wiring them all up in parallel, I connected the resistors directly to the short arms. (Had I been using series circuits, I would only need one resistor for an entire string of LEDs, but I don’t want one burnout or short to result in a “Christmas tree outage.”) I then connected a short (5-10cm) length of magnet wire to each, and then a longer (25cm) length of plastic-sheathed cable colored in black and white for polarity.
Negative should always be black, by the way.
To connect the magnet wire to the heavier leads and wires, I physically wrapped the magnet wire around the subject four or five times so that it would hold itself in place without me touching it. Once this was done, I could then go to town with the soldering iron and some clean solder – once the wires heat up properly, the solder’s surface tension pulls amounts of it into the twined magnet wire, resulting in a really good connection and a very strong solder point, with the added benefit of remaining very thin and easy to work with.
Lastly, in order to avoid shorts inside the model, I applied a latex coating to each soldered connection and painted them with an acrylic paint. This completed the wiring harnesses and provided their exposed wires some extra insulation against shorts.
The Inner / Outer Grilles
After getting all the lights ready, I set them aside and started masking up the inner grilles for painting. These two parts are completely clear in the kit. The portion which is internal to the engine I left masked off initially to avoid getting it contaminated with the paint I was using on the exterior.
These parts pose a rather interesting challenge – they have a series of raised ridges and “trenches” between them, and the only section that is supposed to transmit light is a portion of the “trenches”. These gaps are only about a millimeter wide, but they are about 20cm long…and the lit portion is about 15cm-17cm long, gently differing at the rear to produce a “curved” look to the lighting. See the reference photo and look at where the blue light in the engine grille is coming from to see what I mean.
Originally I wanted to use some very thin plastic masking tape in 1.6mm width, but when I tried this, the edges protruded in a really unwieldy fashion. After a half hour of frustration working this way, I gave up on the skinny masking tape and switched to a liquid masking solution from Humbrol called “Maskol”. This is a liquid product that dries into a rubbery latex that is easy to pull off a surface. Brushing it directly into the trenches was not a good option, as bleed over to the tops of the grilles wouldn’t come free without dragging a chunk of the mask out of the trench as well.
In the end I used a 1mm syringe needle to inject the stuff into the trenches where it needed to go, and this worked out fantastically. (If you have any diabetic friends, or know a veterinarian or doctor, you can probably arrange to get a couple of these from them, so long as you aren’t a likely candidate to be using injectable drugs.) However, I tried to clean the syringe using warm water, and that
caused the latex to set…inside the needle. So, scratch one good syringe needle.
Once the mask was on, I sprayed the parts with Army Painter Matte Black primer, which gave me a nice clean black finish. Some folks go for a deep violet almost indistinguishable from black (which is more studio accurate), but looking at it from a meter away with the lighting up, I don’t think there’ll be anything notably different. I also hand-painted the grilles on the collector parts that go into the front of the engines.
I have noticed since then that the grilles are a little bit transparent on the painted sections still, so I might have to go back and apply another coat of black on them if they look bad when the lights are on.
Using masking tape, I then set out to mask off most of the external nacelle surfaces, leaving only the outer grilles available for view, and sprayed those up nicely too. A little hand-painting of the spots missed, and cleanup around the edges, and problem solved.
At the rear of each nacelle is a horizontal and a vertical fin. The vertical was painted in a ‘duck egg blue’ for the film, so I went ahead in advance and painted it appropriately. It’s worth noting that duck-egg blue is a very light color that can be easily transparent if it isn’t thin enough, and it needs two coats at least if you are using a regular brush. I think with an airbrush this would be a little different.
The horizontal fin will house a thruster lamp, so after positioning the LEDs in the right spots, I then glued them in place. I sealed up the fins and puttied the cracks (which were rather pronounced), and after sanding re-whited the fins. One of them needed a little more sanding after the white was reapplied, and a little more putty to fill in the gaps. Just to be sure, once this was done I re-masked the thruster section and did a second black light-block on the remainder before reapplying white. I also drilled a 3mm hole in the section of the nacelle where the fin would mount, so the wiring would have an escape route.
Note that when handling these parts with magnet wire attached, you do have to be very careful not to bend or pull the wires quickly – always be gentle. I made one error (happy to say it was easily recoverable, see image above), and snapped the wire off the resistor. Really easy to do if you aren’t paying a little attention to it.
Once these were done, I wanted to make sure that no light leakage from the thruster made it into the main body of the engine (because when the warp lights are off, those interior grilles are still clear and need to avoid having bleed-through). I also wanted to practice with a new product I’m using on this model – “Black Seal”. It’s a silicon gel that hardens up into a stiff material, completely black in color, so it makes a great gap-filler for spaces that need to block light. I pushed a little of this into the fin so as to get zero light bleed from the yellow thruster light.
Working with Black Seal, it is almost inevitable that you will get some on your hands, and as a result you will probably leave a smear on the model exterior parts. Don’t panic. This stuff wipes right off with a paper towel, and even after it cures it is just silicon – it should rub right off. I had more than my share of black smears on my engines here before this was done, and they all came off without a hitch.
The Warp Strips and Crystal
At the nose end of each nacelle, on the top, there is a circular clear part that is supposed to
glow blue when the warp drive is engaged. After I retrieved each of these parts, I drilled into them with a 2mm drill bit from the bottom, and glued the blue LED to each one. Once the glue was dry, I hit the outside of them each with some silver paint, and then black to prevent leakage. These LEDs were then connected to the same leads as the LED tape, since they’ll all power on simultaneously.
The strips each got a lead, and I cut some clear styrene sheet to act as a diffusion cover, which was sprayed with dull coat to give it a frosted appearance. Once I fix the strips in place, I’ll cover them with this to further avoid ‘hot spots’ showing from the outside.
In addition, it’s worth pointing out that the external grille has a small window at the front which is intended to light up along with the warp drive. To help direct some of the right light to it, I cut a couple of styrene strips and painted them silver to act as a mirror effect from the blue strips, then mounted them ahead of the windows with a severe angle to direct light out the little windows.
Each of the forward floods is going to receive a tower LED, and unfortunately the sections that will receive these LEDs are only light-blocked from the interior…which means that the tower sections may cause some bleed-through of their light if I’m not careful. To avoid this, I painted each tower black all over except the emitter end.
The section at the rear of the engine for the anticollision strobes are very small ports designed for a clear part to be added here. This port is smaller than the SMD lighting that I’ll be using to provide the electrical effects, so each one had to be widened out a bit to fit. Once they were opened up, I fitted the SMDs to the interior half of the nacelles and glued them in place using canopy glue.
For all of these lighting harnesses, Once the lights are fixed in their places, I’ll then glue the wiring in place in several places using CA and hot glue, bringing the leads all to the connector site where the nacelles mount on their pylons. I also use a bit of masking tape at the ends of their leads to keep the appropriate leads together and to give me a place to label them so I’ll know which is which.
Lastly, for all of these lights, I secured the wiring inside the nacelles with masking tape until I glue them in place (which I’ll show in the next installment). Additionally, I used masking tape to secure the positive and negative leads for each light harness separately, and labeled each one so they wouldn’t get confused. Once this thing is sealed up, if I get those wires confused, the only way to check them is to do a process-of-elimination test with each one to see what lights up with what wires. Don’t want that hassle, so on go the names.