Basics for Lighting Models from the ground up

[ModelMan]

Hey everybody.
Welp, for a first post, I hope this helps. I'm no wizard, but I'm happy to share what I know and how I understand it. I just completed this mini-series the other day specifically covering a couple questions raised here on what's involved with lighting a model.

From blacking out the interior, to mounting the lights, creating lightboxes and baffles, selecting a power supply, running wires, soldering, heat shrinking and everything in between; a ground-up tutorial using the Revell 30th Ann. Cylon Raider as an example.

Note that this is the cheap and sloppy way to do it. I am no expert in any of this. I'm just not rich enough to afford lighting kits, so am learning all this as I go.


Total costs expected:
1 can of black spray paint= $1.
up to 7 leds at .10¢ ea(ebay) = .70¢ (ebay)
up to 7 resistors at .01¢ea. (ebay)= .07¢
Power supply (yard sale) = $1
Heat shrink at $1/yd = ~.01¢
Solder at $1/tube - ~.01¢
Scrap piece of card stock and styrene = .10¢
~6" of fiber optic at $30/100' = ~.15¢
Subtotal = ~$3.04 so far.

We'll round up and call it under $5 for all costs apart from the model kit.

one important note to kick off with. There are two ways to wire: serial and parallel.

Serial means the + from the power supply goes to the + of the 1st led. The - from that led goes to the next led's +, the - of which goes to the next + until the last led's - goes back to the power source -. Benefit: you can use fewer resistors and/or each circuit of led's is the total of the power's voltage eliminating resistors completely. Hair-pulling Moment: if one led dies, they all go out like old fashioned xmas lights.


Parallel means the + and - from each led goes to the + and - of the power supply. Benefit: one led dies, one led dies, the rest stay on. Hair-pulling Moment: each led needs it's own resistor. (oh no!)

This will make more sense as we go. Ask any questions. Correct any errors. This Cylon gets parallel wiring.

Installment 1.
In the case of space ships, metal should not 'glow'. So it is important to black out the inside of the kit. If not, the interior lights will give a soft shine to your model. bad stuff. If you want light to bounce around inside, spray with silver or gloss white next.
Using foil to block light can cause electrical issues, so paint is better.

Analyze where the leds are going, how many and how you are going to power them -ext. or int., battery or wall wart. Figure out how you want to connect the juice to the model. In this case, I am creating several access ports for a wall wart as I want the option to film this from several angles.

[youtube]http://www.youtube.com/watch?v=1drqnHG6RVg[/youtube]


Coming up: Doing the power supply numbers and resistoring those leds.

 

[ModelMan]

Solder on.
Note that I am still sloppy at this. In reality, you need the slightest dab to make the solder connection. Whereas I tend to blob all over. It comes down to aesthetics. The main idea is that you apply heat to one side of the wires and touch the solder momentarily to the far side. The heat and the melting will draw the solder into the twists of wire and freeze it all in place. Blobbing it around means you get more solder on your gun than on the wires and what gets on the wires is a blobby inconsistent mess. No finesse. Either way, it gets the job done.
[youtube]http://www.youtube.com/watch?v=WC20PKto0F8
[/youtube]

Shrinkage
You can certainly use electrical tape instead of heat shrink, but either way, you must seal your connections for longevity and for killing any cross talk which will short circuit your assembly and likely burn out some or all of your leds. Bad juju. Shrink will also stiffen up the connections, making them more stable.
[youtube]http://www.youtube.com/watch?v=bsCQr4W6RE0[/youtube]

First light
So, the wires I cut were far too long. Not a prob, Bob. It's just a matter of trimming them down. Pro's will call this sloppy. I like to have too much up front for unexpected problems, then trim down. It beats having to add wire later. The fewer the connections, the better. What was it Scotty said about over-engineering the plumbing in Trek III?

Keep your scraps. However small they may be, they will likely be useful down the road for another project.
[youtube]http://www.youtube.com/watch?v=S8G8Ut6E2xY[/youtube]

Coming up: Fiber Optics.

 

[ModelMan]

In this one, I hook up two strands of fiber to the led. Heat shrink is typical, but as there are so few strands, I use some regular electrical tape to hold them to the led. I then seal it w/ white glue and once that was dry, dabbed some CA liberally dosed with baking soda, to encrust the assembly so it can never slip free.
[youtube]http://www.youtube.com/watch?v=TMXtJRN_nzw[/youtube]

Here's some non-fiber lighting notes about the wax paper on the engines to diffuse the light. Towards the end, I pick up on the fiber again using my MPC star destroyer as an example. The very end talks about 'blooming' the fiber.
[youtube]http://www.youtube.com/watch?v=i5VVz27zVmM[/youtube]

Before you are ready to seal your model for good, make sure you test your connections! In this case, I pressed on all the wires looking for bad spots. Lo and behold, I found one!
[youtube]http://www.youtube.com/watch?v=pNRKIxDR9iM[/youtube]

Almost there! (Finally!) Light bounces everywhere. So you need to block it off. A light box is simply anything which boxes around the light, such as seen in a previous episode. In this case, I wrapped the black card around the engines for more of a shroud. That encased most of the light, but I still had leak going on . In that case, I simply sliced pieces of card and glued it in to baffle the light. The fiber optics were picking up some of the blue spill, so I shrouded that in it's own piece of card. And that was that. I may mention it in an upcoming video.
[youtube]http://www.youtube.com/watch?v=CqJ_pZ5Wr9s[/youtube]


Coming Up: Final checks and Sealing the body!

 

[ModelMan]

And here is the final installment. A good shake is given to all the wires one last time, ensuring snug fits at all the contact points. Blasting the interior with canned air ensures that there's no fiddle-faddle about to be sealed inside to make an annoying rattle for the rest of its days.

From there, it's glue a little here and there, clamping the body tight, reapplying glue to any loose seams and that's about that.

Of course, the real modeling now occurs with seam-elimination, priming, painting and all that sort of thing. but we all know how to do that easy stuff, right? ( I still suck at getting a good finish myself.)

[youtube]http://www.youtube.com/watch?v=0m5pcmq3qKc[/youtube]

With a few basic skills, electronics is easy. Mastering those (as I still must), means more complicated work will ensue down the road.

Hope this helps all the DIY'ers out there!
Happy soldering!

 

[Chas]

Excellent topic! What a great resource! Thanks for sharing!

Chas

 

[Junkie]

Very cool Tom, thanks for doing this!

 

[ModelMan]

Glad to help. A few of my YT'ers had been asking about lights, so I just rammed this one through as I've got another 5 or so models getting lights right now.

Over the last few months I've poked my head around a few times. Having finished this series the other day, and then seen a need for it here, that was finally it. Took me a long while, but I'm glad I finally signed up (figured I would eventually ;D). You've got a great forum here, Scott.

 

[JMac]

Cool!

Thanks so much Tom,
I've been wanting to try lighting a kit but was unsure of where to start. I've been reading the help and pointer Screaming Samurai Studio got for his BoP build, and now this. I'm going to try it (it might be months from now however - I'm not the fastest builder on the planet by any means).

Contributions like this are why I like this forum.

JMac

 

[ModelMan]

If you want to avoid the seeming hassle of resistors, here's some simple math to consider...

Say your power source is a regular alkaline 9v @ 800mA. You know your leds are just about 3v and need 25mA each. If you resistored each led, you would have to kill 6v off each led (9-3=6). However you can do a serial-parallel wiring setup by wiring your leds in groups of three.

So: power source+ to led1+, led1- to led2+, led2- to led3+, led3- to power-. So that's 3x3 for 9v and 25x3 for 75mA. Now, you can wire 10 sets of 3 leds to give you up to 30 leds running on one 9v battery at full power for about an hour. Remember, that's 10 sets of 75mA for 750mA. Very close to your 800 ceiling, but it should work.

As each set of three leds is serial, if one goes, all three go. However, the other 9 sets of three will stay on. In this way, you can build a modicum of redundancy into your model.

With this basic math example, you can scale up or down to any size power source. Odd numbers get tricky such as two 3v on a 5v or 8v power source, but with some finagling, all should go well. And more often than not, leds will be 2.4v or 1.8v or 3.2v, so the math is never exactly simple, but is ballparked easily enough. But you do want to get into resistors sooner than later.

I highly rec. getting your leds off ebay. Forget Xmas lights. You gotta carefully slice the string up, pull each one out of there, there's tangles and all sorts of hassle. Also, you won't know the mA or v of each, though you could ballpark it. At 100 leds for ~$10 shipped of any of nearly 1 doz colors and all arriving within a week ina a nice little baggie. You've got no hassle and typically the seller lists the power numbers on the sales page and will tell you more important info like the degree of visibility, the candle power and more. That's stuff for another post.

And quite often, there are sellers that throw in the resistors for free. Just tell them the power source voltage you have and they will do the math for you. Just say you want 12v, 8v, 6v or whatever nd that's the apropriate resistor you get for that exact led. No resistor math involved, just ensure you have the wallwart to match. Later on, you can grow into the more complicated math. Just check the sellers rating and make sure you are comfortable with all the terms. I've spent about $100 on these sellers and not been burned yet. And if I am, I'm out $10. If I spent $50 on a seller and got burned, I'd be disappointed, but the buyer protection can help out on that front.


Have fun!

 

[ModelMan]

And again, I'm no expert. So please call bull if you see me leading folks astray! I also want to learn and make sure what I think I know, I really know! ;D

 

[tetsujin]

In your soldering video you mentioned stranded wire, and how you need to find smaller stranded stuff...

The wire I use for most of my projects these days is 30 AWG stranded teflon-insulated wire. The part number I used to use to order the stuff from Digi-Key is apparently no longer viable (and searching through their site it seems 100' spools are pretty expensive) - but you can find wire on Mouser... Just go to "Products->Wire & Cable->Wire - Single Conductor" and enter 30 AWG as the size, "apply filters", then select all the options for stranded wire (omitting "solid") and hit apply again...

Bottom line, you can get a spool of 100' of 30 AWG stranded wire (about 1mm thick, including insulation) for about $24.

Originally I bought the wire when I was building this kit. See how the commentary talks about "arm unfolds to double length"? I lit up the dragon eyes at the end of the arm... So I ran two wires through the whole length of the arm (five points of articulation) and the wiring still works nine years later. It's not invincible wire but it holds up pretty well.

Of course, just 'cause I use that particular wire for just about everything doesn't mean it's always the right choice... Small wire is less durable but also more resilient than large wire. Durability is mainly an issue in places where there's a single point of physical stress - like a solder joint, or a moving part where all the motion on the wire is being forced onto a single point. Because it's smaller, it requires less clearance to be able to move around without breaking. Slightly larger wire can also be easier to work with - and solid-strand wire is definitely easier to work with. Wire-wrap wire is fantastic stuff, so long as you're not bridging any moving parts with it.

Nice Bebop soundtrack, BTW...

 

[Shark]

great thread, I know I will be referencing it in the future.

 

[JMac]

great thread, I know I will be referencing it in the future.

I second that. There is a ton of information here. Thanks.