Thanks man. I ended up doing this in about 20 hours spread out over 5-6 dedicated sessions. As far as actual skill, there's not a lot involved beyond the basis stuff required to do any LEDs. I've done pretty extensive write ups before on my X wing page (https://community.fantasyflightgames.com/topic/220901-lighting-and-repaints/) and it all pretty much applies here. But as far as this specific ship, lemme see if I can give a write up.
Step 1) Determine the scope of the project and game plan everything out. This WILL change as you tear it apart. I like to do some google searches for pictures of the ship to determine what I'm interested in doing. But it goes beyond just deciding what I want the end product to look like. I also decide where I'm going to put the switch, and how I'm going to recharge it. I also take this opportunity to do any research on tearing it apart if others have already done so. I make my shopping list of components I'll need at this time to make sure I have everything in advanced so I'm not waiting for something to arrive (which I end up doing anyways).
For the ISD, I decided that I wanted FOs on all hull sections, engines, and the ventral docking bay. I figured the three large engines were going to be dedicated LEDs, and the smaller would be shared either through FOs or through and ambient glow behind them. The docking bay I figured that I would either have to side light it with numerous large FOs or potentially use a side glow FO. I had no clue where I wanted the switch/recharge ports, but I figured I'd find somewhere.
Step 2) This is the first hands on step, tearing down the model. I'm not the best at this as I always end up marring the surface in some location at least, but in general, I slide a knife between the parting lines, and wiggle it back and forth. Once a post breaks apart, you should be able to locate where the other posts all are - focus your attention right at (or on either side if you can't get right on it) the post. In addition to splitting the hull in half, there are always additional components that need to be taken apart, but take a look at whether or not it needs to come off before taking it apart. Minimizing the tear down is always a good thing. Don't be afraid if something breaks - it's almost always a clean break that you can easily repair.
My research on how other people did this yielded a concern that the rear posts where a PITA. I even stumbled across someone (I believe on these forums) that ended up cracking the hull instead of the pegs. So after deciding that they weren't going to come apart, I went ahead and just cut them from the inside. There were a total of 3 small bits that ended up breaking off, but they all glued back on perfectly.
Step 3) This is where the fun begins. And I actually mean that, I enjoy these next few steps. Now that everything is opened up, it's time to start planning out where everything will go. The main thing to determine is the battery location as that is the largest item. But it's also important to take a look at wiring routings, and where the LEDs are going to go. This is also the time to determine any plasticard that'll be needed, and where that's going to go. You also have to determine what needs to go and what needs to stay. Striking the right balance is critical - remove too many and it's a PITA to put back together. Leave too much and it's a PITA to get everything in.
Well I screwed this one up. I thought that there was going to be plenty of space inside, so I didn't worry much about internal space and pretty much ignored this step, and ended up paying for it later on (which is why this step is there). After I ran the FOs for the sides, I realized that I was going to have to take out more posts than I initially intended to - and its much harder to do that when there's a ton of fragile FOs right next to the dremel location.
Step 4) Now you get to execute step 3. You WILL want a dremel for this. There's not much to be said about how to do this, you'll learn short cuts and techniques as you go. Posts are pretty easy to remove, and sections that you are opening up can typically be drilled through, and then widened with a routing bit. Finally, the engine diffusers (such as on the CR-90) are best to come from the back of it, and just take off ~1/8 of plastic until only the diffuser is left. A hobby knife can help clean up the edges to provide a crisp look. Cutting out the cockpits can be simple or difficult depending on if you want to leave the window supports. If you're fine cutting them out completely, use a cutter disc to just open up the slot. It'll make it nice and straight and level. However, if you want to leave the vertical supports in place, then you'll have to drill out enough of it to fit a small hobby knife and work very carefully to cut it out. The good news is if you mess it up, you can just cut out the vertical support anyways.
A bunch of this isn't really relevant to Armada since you're really never going to be lighting up cockpits on this scale. But this is where you'll cut out the area of the hull to create an opening between the command decks and the main part of the hull.
Step 5) Paint it black. All of it (well, just the interior). Trust me, it'll help with light seepage. And it's super easy (though time consuming) to do now instead of later. You've cut everything out that needs to be cut out, and you haven't installed anything yet.
Yup... I ignored this step too and regretted it. I ended up having to go back through at the end and paint all of the FO source LEDs black and the hull around them with the ship only 1'' apart because I was getting very concentrated yellow light seepage through the hull. It's almost like I've dealt with that issue before and have a plan as far as how to prevent it from being an issue again...
Step 6) If you're using fiber optics, this is when you want to run them. I will point out that if the ship is double walled, you will want to dremel out (in step 4) the interior wall. FO's don't go well through two walls. In general, I find that drilling from the outside in works best for FOs, it typically leaves a shaving on the inside to help you locate each hole. For sizing the FO cable, I find that I'd much rather waste extra than deal with just barely enough, so I'll run it from the location of the LED to the furthest point, and then add about 3-4 inches (depending on how far away that is). When threading through, I start at the furthest point and go back towards the LED. Once all of the FO's are wired and the cable is in the position you want it, it's time to glue them in place. DO NOT use super glue. This actually attacks and breaks the FOs. I've had good luck with just white glue (you know, the stuff you use in school?), but I used to use hot glue, but that ends up being messy. I've heard good things about silicon as well, but it seems like it'll have the same issue as the hot glue. Whatever medium you use, after you get it in place, wiggle the FO in and out a bit so the glue actually goes into the hole instead of on top of it. Once it's dried, you should be good to snip the FOs down to about an inch. I leave an inch to minimize the chance of the external FO getting caught up and pulled on anything - that will break the glue. But in case I pull it from the inside working with the rest of the installation, I still have some extra to thread through.
Yup, this is all applicable to any FO project. I've never worked on this quantity before though, so I did an additional step of combining numerous cables into a single LED source. Typically I'll use a 64-filament cable and use a single LED to light those, but I a ton of cables, partially due to the quantity, and partially due to ease-of-use aspects. I ended up cutting about 1/2'' off the LED side of the cables and using heat shrink to combine 3-4 cables into a single 5mm LED. Except that I didn't really plan out where everything was going and had the LEDs poorly placed within the ship. Another reason to execute step 3 better.
Step 7) If there's any sections that need plasticard installed, now's a good time to do it (make sure you paint it!). Though if you needed to run FO's through it first, then it would have to be at least slightly in place already. In addition, this is a good time to glue in place the diffusers as well, both on any cockpits and engines. I've found that any time you can glue the diffuser in from the back, better to go with a milk carton, but any time it would have to be a perfect fit, you're not going to get it with a milk carton, so you might as well fill it with hot glue. If you want a smooth surface at the end of the hot glue, you can use parchment paper (ask the lady for some), insert the hot glue, and then hold it upright so the parchment paper is on the bottom - the glue will drip down and cool against the paper, which should peel off afterwards.
None of this was needed for the ISD. I actually had to come up with a new way of lighting the engines. On previous projects I've always had the LED behind some sort of diffuser, but the Star Destroyers have the issue of being this large cone that's all supposed to be lit up, but only a small section is actually attached to something. So if I cut out the small section and place a diffuser there, then that's the only part that's lit up, and the rest of the cone is dark. I tried filling the cone with hot glue (with the intention of it providing a large diffused surface), but that was just a colossal failure. In the end, I found that popping the LED through into the focal point of the cone, and painting the cone with a glossy reflective paint worked really well.
Step 8) Almost done. Time to install the LEDs for all of this. I've found that it's typically easiest to solder on a length of wire to the end of the LEDs, but leave it at that for now. Green stuff is a great way to secure the LEDs and hold them in place in the center of the engine. If you're lighting up a cockpit area, drilling a small hole through the plasticard and inserting the LED through there is also a good way to secure it (and then glue/tape it to the backside). For the FOs, I use some heat shrink to hold the LED tight to the FOs and then some tape to hold everything together.
This is where I started struggling - I hadn't planned out where the LEDs for all of these FOs were going to fit. I ended up pushing all of the hull FOs along the right side of the ventral hanger, and the command deck FOs on the left side. So the LED for the command deck is actually by the bow of the ship, and all of the LEDs for the rest are back by the stern (off centered since the battery and engines were centered). This is also about the time that I abandoned any hope of lighting the hanger.
Step 9) Finally, time to snip the leads to length and solder then to the resistors and to the battery. This is also a good time to figure out where the recharge cables and switch(es) are going to go. Not much to discuss here, I've found that using bits of metal plates along with magnets are a good way to have hidden recharge cables. As are removable turrets.
By abandoning the hanger, it allowed me to make that the spot for the switch and recharge ports. I had planned on doing a dual switch arrangement so I could have it running in one of four ways - On from Battery, On from Wall, Charging + On, Charging + Off. I was still of the opinion that this was going to be exclusively a display piece so I was planning on having it on 24/7, without having to power it through the battery and continuously recharge the battery. Turns out I didn't have enough space, but oh well. Once that was abandoned due to space reasons, it was pretty straight forward to solder everything together. I like to do it in two halves, and then put them together as the final step.
Step 10) Time to put everything back together. Before gluing everything together, I like to test it for 24-48hrs or so prior to finalizing it all. I typically put glue in a couple of posts, and then in a corner or two when I've cut out a bunch of the posts in a row. This is typically an easy step. And once it's all set, you can trim the FOs flush. Plyers are the best tools normally, but sometimes you'll need a knife. And if you plan on painting it, you'll want to leave a bit of the FOs exposed so you can paint it, not worry about covering the FOs, and then cut them at the end.
This was actually a very challenging step for this ship. I packed so much into it that it didn't really want to close. Plus the only pegs left were two in the rear, which meant the sides had to be glued in place, so I couldn't even fudge it with a small non-noticeable gap. I spent several hours (though not dedicated) gluing on section, holding it secure with numerous clamps, and then moving on to another section once it dried. This was abnormal though, and if I was to do another ISD it wouldn't be as bad. And for trimming the FOs flush, I've actually migrated on to using cuticle cutters for that - they have a very fine and sharp point, allowing you to easily get right up next to the hull.
Hope this helps you get an idea of my process.