Bridging and potting a custom P60 pill

Cheese_05_70

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Hi guys I just signed up to the forum. Been reading off and on for a year or so. I have built a few lights burned up a few components in the process as well. Got a couple rookie questions.

I'm building a custom mini Mag light so it will be turn top. What's the best way to bridge the driver and pot it? The first one I built I potted it with fujik and tried to bridge well that was a mess and a mistake. Couldn't solder the driver to the heat sink because of the fujik. So everything is basically held together by pressure. The reflector does put a good ammouny of pressure on everything to keep it secured. It just doesn't settle well in my mind.
My next one I was thinking about bridging the driver then filling the void with a thermal compound ( recommendations please) from the top through the led lead holes with a syringe? My heat sink is solid copper should I try to solder the star on or get something to glue it? I make sure that the pill is completely flat along with the star. I know some of the basics just looking to fine tune it with your guys help.

I have another light with an aluminum heat sink whats the best option for this one for the driver? Just use thermal adhesive? Solder a piece of copper wire to the heat sink and then solder driver? Glue a piece of copper wire then solder driver?

Thanks
Colby
 

DrafterDan

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maybe some photos would help. I have not worked with maglites for many years, are you speaking about a modern LED version? Why would you bridge the driver, to have it run direct? Aren't all mini's a turn top?

For potting, I prefer non-reactive silicone. Just don't get it on things you want to later solder.
 

Cheese_05_70

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The mini mag is just the host I'm using. I drilled out and the head and have it custom fitted with a p60 pill that's custom made for improved heatsinking. I'm using this driver: http://www.mtnelectronics.com/index.php?route=product/product&path=67&product_id=554 I'm running at 3A on a nichia 219c 5k 80+cri led. The driver says it needs bridged and I potted it as well but my bridging didn't go good because I already potted it with fujik before trying to solder bridge it. Its held together by pressure from the reflector. There's a shelf inside the head where I stopped drilling and the pill rest on that. The the reflector pushes down from the top to hold everything tight. It is twist head and nothing moves but it makes me a little uneasy twisting it all the time. Basically whats the best way to bridge and pot the driver and hold down the led? Its all together at the moment so I don't have any pictures but I'm getting ready to build another one and want to do it right. Does it work to bridge it then pot it from the top through the holes for the led leads? Whats the best to use? Artic alumina in a syringe? Then use some thermal adhesive for the star?
 

DrafterDan

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Okay, so it's basically the format of a P60 pill, I can work with that. The bridging just means you need to complete the negative side between the driver and the pill/ host/ tailcap. Recently, I use a flat-nose punch to stake it in place in the pill, and then solder.

A P60 pill
dzaq2H.jpg


A pill for an Okluma.
I've experimented with making notches and running wires between the neg of the pill to the body of the pill. A bit cumbersome, but it worked well.
beI2WG.jpg


I squeeze in the non-reactive silicone into the pill prior to buttoning up the driver. Because your driver is a buck, and loses the difference in input voltage/ output voltage through heat, maybe silicone wouldn't be the best stuff. Just look for a thermal compound that doesn't have any conductivity, because you are flooding the business end of a driver with it.
 

Cheese_05_70

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I like that notch idea might have to try it some time. The few times I have potted with fujik and Aa I potted it before I soldered the driver down. When I would try to solder the driver it didn't want to stick because the fujik or aa was contaminating my solder joint. Both the driver and pill was pre-tinned. So I have been thinking about soldering driver and then pott the pill through an opened up led wire hole or drilling a small hole in the side of the pill and using a syringe?

Basically whats the best way to bridge and pot the driver and hold down the led? Does it work to bridge it then pot it from the top through the holes for the led leads? Whats the best to use? Artic alumina in a syringe? Then use some thermal adhesive for the star?
 

DrafterDan

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That's why I've got the tape on there. Silicone is a great way to ensure no solder will ever stick there.... :)

Just clean it really well before soldering. Making sure you are using flux (i like those marker-type pens that have liquid flux)
No easy way to get the potting in there. The non-reactive silicone I use has a nozzle, like a small version of a caulking tube, so it helps direct the flow. I push the wires into place (like the above photo) and then squeeze in just enough not to spooge out the holes, and you're golden.
 
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