I’ve just got my parts for a C8 build and ran into a problem. I wonder if this is known and if there is a standard solution for it…
I have assembled the pill and have soldered the wires to the LED base plate but my soldering skills are not the best so the solder “blobs” are a little high. When I attach the reflector it is going to create a short circuit over the solder points on the plate. With the C8 came a little white plastic “sleeve” for the emitter, but it is not wide enough to cover the solder points.
I’ve taken the liberty to linking to a photo from this C8 review thread to assist in explaining what I mean (sorry if it’s not OK link like this, let me know and I won’t do it again):
As seen on the photo the white “sleeve” does not cover the soldering points and the reflector’s base is just wide to cover and short them. Even with solder points that are well done, this is cutting it a little too close in my opinion. The reflector will lead electricity, I tested it with “beep” mode on a DMM, and because the little white sleeve is so thin it won’t take much to short the solder points.
Anybody run into this before? What to do? I don’t won’t to solder again as I’ve done it a little too much already and the lead from the negative solder point to the emitter has loosened a little.
and some times i just drill a very very small hole next to the solder pad and run my wire up through it and it makes it more flush with the board than a large ball
and if those gaskets does not work try using plastic and cut to size ?
I didn’t know such things where purchasable. Thanks. I’ll be getting some of those.
Good tip. I might try that next time.
Yeah, I considered these options. Making a plastic washer will be quickest while I wait for gaskets. I Just think it’s a little weird that the host does not come with a gasket already.
They assume you are using 30 gauge wire - very thin crap, so the solder connections have a much lower profile, and the white plastic centering peice will be enough to keep the reflector from touching. Many budget lights don't come with anything covering the connections because of the super thin wires they use. We upgrade to heavier gauge wires typically, so we sort of create the problem.
A wider insulation gasket is not going to help you here, the reflector will not sit deep enough over the led for correct focus if the solder blobs stick out too high.
It is a design flaw of the Convoy C8 that it has a pill made for 16mm boards, and it is not exchangable with a 20mm-board pill that is used in most other C8's (like the Ultrafire host from Fasttech, which is a very nice host by the way). If you want to use a different reflector (i.e. the smooth C8 reflector from FT) this 16mm board problem is even worse.
The best solution is to make your solder blobs as flat as possible. How I do that is first tin the solder pads on the board very slightly, so that a very flat layer of solder is on it. Then bend the led-wires into shape, flatten the wires with pliers, then tin the flattened wires with a small bit of solder. Hold the wires on the solder pad and melt the wire to the pad. This way the solder hardly sticks out and hopefully the reflector does not touch it.
With some reflectors/leds that still do not work (with dedomed emitters the focus is very critical, the reflector has to sit flat on the board, without the insulation disk), the way I managed to get it working is solder the wires almost completely outside the solder pad on the board, so that it barely touches the solder pad and just not touch the side of the pill. This is tricky, but it does work well if you succeed.
For correct focus in the Convoy C8 the reflector sometimes has to sit so deep over the led that the pill has to be screwed out a bit to get the reflector touching it.
Using Kapton tape on the reflector as insulation does not work well, when screwing down the reflector, it usually just rips off.
You see, the Convoy C8 is a very well made flashlight the wrong way.
djozz is on the right track, but there are other issues as well. If you have some 16mm stars and some 20mm stars, notice that the Noctigon stars at 20mm have the contact pads pretty far from the outer edge. Trying to clear a reflector base with a larger 20mm star still won’t do. So the real issue lies with the build of the reflector. The base is too wide. Fix that, and you’ll have gone a long way towards solving your problem. You can take a flat blade screwdriver and press the solder blob while applying some heat with your iron, mashing the blob as flat as possible, that will help. I even make a slip cover for the emitter out of aluminum for when I’m soldering, to keep the solder and wire as far to the outside as possible, leaving the pad clean towards the emitter. ( bored a hole in the end of a half inch aluminum rod, place that over the emitter when soldering pads to keep clearance and protect the silicone dome from lux pops, with this piece of aluminum sitting halfway over the pads, solder won’t flow to the inside half of the pad when being careful doing the soldering. This keeps the wire on the very outer edge of the pad, pressing it with a flat blade or end of the file keeps it flat, helping to allow for maximum clearance)
The real trick is filing off the base of the reflector to gain some clearance. I have used a dremel for this, but it heats up the aluminum sometimes to the point of making the silver plating buckle and bubble in the reflective area. So now I use a file. Spend some time, carefully file off the base on an angle and get that clearance you’re looking for.
Epoxy on the contacts just adds more thickness, as do the spacers or insulation discs. But I have used them quite a bit too. When all else fails, a thin strip of brass sheet can be soldered to the contact pads, with the wires soldered to these strips outside of the area the reflector base covers, or even under the strip with insulation between the wire and the pill.
Thanks for the tips. The soldering tips will have to wait until next time as I had soldered so much that the solder point for negative wire came loose of the base. I didn’t dare touch it again with an iron. So I ended up using epoxy to isolate the blobs and fix the loose solder point and lead that I managed to overheat and loosen from the base. Then I filed down that reflector so much that there is no chance of shorting. What I have left is not pretty but the aim of this was to learn, and learn I did
As many as I see in all my C8 even if you use 20mm star the two solder joints are still able to interfere with the reflector’s base. You really have to get the solder joints as flat as possible or file down the reflector’s base a bit.
Putting a kapton tape on top of the two solder joints is one of the good ideas too, and when you screw down your bezel make sure you don’t rotate your reflector too much in case of ripping off your kapton tape. You can use finger to press on the lens while screwing the bezel to minimize the reflector movement.
