# Convoy S4 Build (Flash light)



## Hrawk (Oct 25, 2010)

I recently did this tutorial / build log for a few members on another forum to help them out. I'm posting it here as you never know, a few people might find it useful. Everyone needs a good flash light.

Introduction

Hey folks,

Several times now when I have talked about building flash lights, several people have mentioned they'd love to see a step by step guide to building one themselves. Well today, in what us alcoholics like to call a 'moment of clarity', I decided to do just that and document my latest build.

Here it is, a step by step, picture heavy build of my most recent job. Like, share, subscribe. I couldn't care less. Print it out and use it as toilet paper for all I care.

You're still reading? Cool. Today we are going to build the Convoy S4. I purchased this kit from Fasttech for $15.17. SKU 1311101

Look at that sexy packaging.










Inside the box we find some nice foam and all the parts we need to get started. The one thing that really bugs me about the way it's packaged, is that they stick the reflector in the same bag where it can get scratched and dented. FFS people, there is plenty of room to package the reflector separately.










Right, pull all that crap out of the bag and make sure everything is there. Nothing worse than getting half way through a build and realising you are missing a piece. Leave the reflector and glass in its own bag for now so you don't get sh1t all over it.










Here's the basic tools you are going to need.
• Soldering Iron
• Side cutters / flush cutters
• Tweezers / Needle nosed pliers
• File
• Helping hands (You can get by without but damn they're handy to have)
• Multimeter (Again, not necessary but a good thing to have)
• Thermal paste
• Silicone Grease
• Soldering flux (It's pretty easy to screw sh1t up if you don't use this)
• Torch or other light source for checking really small sh1t in poor light

Not pictured
• Solder
• Circlip Pliers (Tweezers will work of you don't have them)
• Q-tips
• Paper towel
• Beer / Weed / Vodka
• Sandpaper (400-800 grit silicone carbide paper works best)










Got all your tools sorted? Not missing anything? Great, let's move on. Today we are going to use a Njang 105c driver board, again from Fasttech, SKU 1186301 and a Cree XM-L2 T6-0D emitter from you guessed it, Fasttech, SKU 1570602










Right, you have all your parts, your emitter and driver, stick that crap back in the box so you don't lose anything. Nothing worse than knocking something on the floor and losing it or accidentally putting that soldering iron down without looking and burning up one of your o-rings or rubber cap for the switch. Yup, I've done it. It sux.


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## Hrawk (Oct 25, 2010)

Switch

When building, I like to start from the bottom up. Lets start with the switch.

Now normally, with a Convoy S4 kit, you have to assemble the switch yourself. For some reason (just lucky I guess) the switch in this kit came pre-assembled. It's pretty straight forward stuff though.

Take some flux and put it on a Q-tip. Take the switch PCB and the spring, rub some flux over it then solder it to the board as shown in the pic below.










Now do the same with the switch and the other side of the board. Usually the switch has rather long legs on it and you need to trim them shorter and fold them down as shown below. Solder each side of the switch to the corresponding tabs.










Now this next step is not 100% necessary but it's sh1t like this that separates the men from the boys. Take out your piece of sandpaper and clean up the mating surfaces of the switch retaining nut and the switch PCB. This will ensure a clean, flat surface which provides maximum contact and minimal resistance.










Got that done? Good, time to put things together. You'll want your tweezers or circlip pliers for this step. So, the below pic shows the order of assembly. Start with the switch housing, insert your tailcap / button cover, next goes the switch support washer, switch next and finally the switch locking nut. Be aware that in the Convoy S4, this is reverse (left hand) threaded. Pop it all together as shown and you're all done with the ass end of the light.










Look at that, you're 1/3rd of the way to finished. You rock.


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## Hrawk (Oct 25, 2010)

Body

Ok so the switch is all done, let's move on to the body. Nothing too complicated here.
First of all, grab that piece of sandpaper and sand each end of the tube. We do this to remove any anodizing and ensure we have nice clean, bare metal for electrical contacts. Make a few figure 8's with each end till they are nice and clean / shiny.










Time to pull out that silicone grease and 4 of the red o-rings. Using a small screwdriver, toothpick or something small, generously place some grease into each of the four o-ring slots on the body and work it around.










Slip the o-rings on, add some more grease and smooth it all around each end. This grease protects the o-rings and makes assembly nice and smooooooth. Wipe off any excess and we're done with the body, almost. Take the body tube and press down on some paper towel, twist. Clean up any crap or grease off the ends of the tube. Remember, we need these to be clean as possible as they are electrical contacts.


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## Hrawk (Oct 25, 2010)

Pill - Prep

Now we move onto the cool sh1t, the heart of the beast, the pill. Ok, grab your driver out. You will notice more often than not, it has a pair of 'ears' sticking out. We need to remove these by cutting or snapping them off. Then take the file and smooth them over.










We need to make sure the driver fits into the pill. File / sand until it fits nice and snug. It fits ? Cool, take it out and put it aside.










Just like we did with the mating surfaces of the switch, we want to clean up the driver side of the pill (where it will make contact with the body. Don't need to remove much, just get it nice and clean / shiny.










Moving on, we do the same thing with the back of the emitter. We're looking for a nice smooth, clean face for mounting into the pill later. Be very careful not to damage or blemish the emitter. Wear some of those cotton gloves if you have them.


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## Hrawk (Oct 25, 2010)

Pill - Driver

This is where the helping hands come in particularly handy. Insert the driver into the pill and mount it up to work on.










Grab one of those q-tips and open your bottle of flux. Add a few drops of flux to the q-tip and using it like a marker pen, rub it over the one edge of the pill and the driver board. We're about to solder the two together and flux makes everyone's life easier.










Here you see where we've soldered the two pieces together. Be careful not to go crazy with solder, we just need a solid connection between the two surfaces. If you are using a 'no clean' flux, great, if not, take a clean q-tip and some alcohol (isopropyl) and clean around the joint.










Soldering is done, grab that file and clean it up. We want it nice and flat but don't go so far as to remove all the solder from the join.


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## Hrawk (Oct 25, 2010)

Pill - Emitter

That's one side of the pill done, now comes the business end, mounting the emitter. I forgot to take a photo of the first step here which is placing a nice dollop of thermal paste onto the surface then pressing the emitter in place. Slide it around a bit, twist it too and fro, spread that paste out as thin as possible. Oh, and for the paste, less is more. It's job is to fill in the tiny imperfections on both surfaces. We want as much metal to metal contact as possible with the paste filling in the rest.










The length of these wires is too damn long! Time to trim them shorter and strip the ends ready for soldering. 5-6 mm of wire left is more than enough.










Get that q-tip out again and give the + & - pads on the emitter boards a good clean. Tin the pads and the ends of the wire with your soldering iron.










Use your tweezers and bend the wires over to touch the pads. Hit them with the iron. They should connect pretty easy now that you've tinned both sides.










All soldered up? Good. Slip on the insulator.


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## Hrawk (Oct 25, 2010)

Reflector

We're getting close to the end now. Time to get started on the head. Grab the head, your glass and reflector. If you've been paying attention, these are still in their plastic bags staying clean. Go wash your hands. Now.










Right, grab that reflector, one of the red o-rings, a screwdriver / toothpick or something similar and the silicone grease. Use your tool to work some of the grease into the o-ring groove on the reflector.










Slip the o-ring on and give it some more grease on the outide. Wipe up any excess.










Find the glass and the two green o-rings. Start off by placing one of the green o-rings down the head, then the glass, then another green.










Insert the reflector next and push down.










The outside o-ring likes to squeeze out of it's home at this point. Use a finger nail, tweezers, whatever, to push it back in. You'll want to do this after the next step too.


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## Hrawk (Oct 25, 2010)

Final

Ohhh we're so close, can you feel it ?

Take your completed pill and screw it into the head. Slowly. As you tighten down, keep turning it over and make sure the green o-ring mentioned previously is kept pushed into its groove.

Now we don't need to go crazy tight here, once both o-rings (green) are compressed a bit, that's enough. Too tight and you will squeeze the o-rings out of place or worse yet, crack that glass.

Everything's seated nice and securely? Good. Time to add some thermal paste to the lower set of threads. Don't go crazy and try not to get any onto the driver. The thermal paste here helps a lot in sinking heat from the pill to the body of the torch.










Cool. Screw the body onto the head nice and tight.










Tell it you love it and shove your battery up it's behind.










Screw the tailcap / switch on and BOOM, you have your working torch!










The OP (orange peel) reflector on the standard S4 kit gives a really nice, smooth hot spot that blends slowly into flood. These are not a thrower by any means but for most general purpose use, give an excellent beam.


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## Hrawk (Oct 25, 2010)

Well I'm done here for now.

For anyone who has found this useful, be sure to kudos my posts or even better, tip me something.

I've put several hours into this post with the build, photos, editing and posting. Please, show your appreciation.

If you couldn't care less, that's cool.

If however you thought this was great, and would like to see more posts like this, post below telling me what you want to see. If I get enough tips on these posts, I'll very hapilly purchase all the pieces for the next build and do the same.

I'm thinking either a C8 build or a WF-501 build. If I can cover 50% of the cost with tips, I'll get right on it.

Party on people and remember, Listless spectre is still a cunt.


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## Danny0663 (Mar 15, 2011)

Not really into flash lights, but that was dam well documented. Me Gusta.


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## leon13 (Oct 4, 2012)

wow why didn't al teachers do it like this,me as a " part time electric legasteniker "see now a light at the end of the tunnel ;-)

that was really well made.

cheers


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## Neo Catapults (May 28, 2014)

Unbelievable!!


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## carboncopy (Jan 14, 2014)

Great build-along!

Thank you very much for the tutorial!


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## oldmiser (Jan 22, 2014)

Excellent build my friend....Very well done with nice photo instructions....~AKAOldmiser


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## BeMahoney (Jan 26, 2014)

Really nice tutorial! Liked your humor!

Thanks for working this out!

Kind regards,

Be


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## Hrawk (Oct 25, 2010)

Cheers fellas, glad you liked it.

I figured we have a few outdoor hunting types here who use lights and may appreciate it.

I'll hold off for now on posting my ITX based, networked attached storage build . . . .


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