# My High Power Mag Switch solution



## Chodes (Oct 16, 2008)

Finally got hold of some Judco switches. I got them from Lighthound - same switches used in Leef system. Unfortunately looks like they are the "long shaft" version of the switch , I'd prefer as small a switch as possible.
Anyway, here's my home made switch. Used some blank circuit board , some spacers , 3mm screws, fair bit of JB weld (metal epoxy)
The big block of JB weld on the front is intended to act as a heat insulator.
I moulded the epoxy inside an old mag tube so it's a perfect fit.
I had to grease the tube or the switch assembly won't move very easily.
I tapped a hole in the bottom so fixing is via external screw - 6mm so I can use a 6mm stainless ring to secure the switch and use as a lanyard point.
It's a fixed height for the socket obviously- I've found thet height good for most of the Osram 64 series bulbs which I'm (now) using it with.

MK2 switch is almost finished , MK3 I'm going to use a complete Kui kit on the front just to make bulb alignment easier.


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## Juggernaut (Oct 16, 2008)

Neat:thumbsup:!


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## cnjl3 (Oct 16, 2008)

That is one hell of a switch!
What supports the rubber switch seal to help keep the guts dry?


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## rolltide (Oct 17, 2008)

Great Job!!!!!

That is a great idea. I will try to do something like it, only I am going to use a stock switch and cut the middle section out. I have been trying to think how to mount the switch between the two end pieces. Now I know, thanks to you.

Roll Tide


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## mdocod (Oct 17, 2008)

great work!!! very nice switch job there! 

So you have to drill a hole in the mag for the final connection? I wasn't quite clear on how you were making contact to the body and holding the assembly... Yours Looks really nice for a home-brew 

I got my "short" versions of the Judco from digikey. I ordered quite a few, if you want a "short" version to experiment with send me a PM 

Eric


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## Bullet Bob (Oct 17, 2008)

If you ever decide to make these for sale I definitly could use a couple. Let us know if you would be willing to crank some of these out.


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## vestureofblood (Oct 17, 2008)

+1 for the WTBs Nice work.


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## Chodes (Oct 17, 2008)

Eric , thanks very much for that offer. PM incoming.

Mk2 and Mk3 have been under construction at the same time.
Mk1 just needs something to support the Mag rubber boot (unless I find a different boot.) Good 'ol JB weld to the rescue again for the MK1 switch.

MK2 is much more serviceable , thinking of using the very top of a mag switch for the boot retain solution for that one. It's about 4mm longer than a stock Mag.

MK3 I used a Kui kit. Totally serviceable , the switch itself is a very tight fit, clamped in place by the housing bits. So easy to replace the switch in this one if it fails. Switch housing is secured by 3mm screw , externally.

MK4 will have an internal securing screw as per Mag switch. 

MK2:










MK3:





















The whole family:


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## VegasF6 (Oct 18, 2008)

Very neat work. 

Just FYI JB Weld is only good to 500F. JB Kwik is even worse. I had both fail on me trying to fix a BBQ. I had no luck finding a high temperature epoxy that would air dry and was readily availible. I am sure that you are well within that range mind you, just wanted to point it out. Reason being I was considering trying to pot a bulb with it, and realized it would fail.


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## rpage53 (Oct 18, 2008)

VegasF6 said:


> Just FYI JB Weld is only good to 500F. JB Kwik is even worse. I had both fail on me trying to fix a BBQ. I had no luck finding a high temperature epoxy that would air dry and was readily availible.


Epoxies aren't good for high temperature applications. So called Hi-temp epoxies are only high in relation to other epoxies (which you can melt with a heat gun). JB Weld is a little bit of regular epoxy mixed with chalk and iron filings.
However, if the light exceeds 500oF, you have other problems.

You probably need a ceramic adhesive for your BBQ which can withstand 1000-4000oF.

Rick.


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## VegasF6 (Oct 18, 2008)

Rick, hey thanks for that tip. I had given up finding any way to repair it and actually bought a new firebox for the old Weber. But i will still pick up some ceramic adhesive, that sound very handy.

I guess there are reports of ROP builds melting solder from the contact's, probably in excess of 400F. I would imagine some of the high powered 100+ watt projector bulbs run quite a bit hotter than that? So you could potentially have some very high temps. But, I would also think that a bi pin lamp in a ceramic socket, like above, would be fine? The stand offs provide isolation both by ventilation, and simply space. And of course the reflector works as a heat shield in itself. 

I dunno, I just wanted to point it out, I know very little about hot wires at this point.


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## Chodes (Oct 18, 2008)

Looks like I'll be testing the JB weld out for heat then..
It was supposed to be my super high temp switch , might be re assigned to more moderate duty.(or install fuse in the tailcap and do some field testing )

My MK3 failed! Only about 20-30 actuations before the switch became momentary only. Was still clicking properly, button was staying in "low position " when on. Luckily that housing is super easy to replace the switch so I've done that. Was using 64458 - about 10A at around 19v, seeing as it failed so quickly, assume it was a dud switch.

I've got the rubber boot secure solution by mistake. On the MK2 housing the switch is a bit low, or the plate on top to high.. As it turns out , the plate on top is just about perfect for generic KD/DX rubber boots. The mag boot also works, but is a little loose. It did not fall in with a bit of testing , but it would be easy to make some thin shims and build it up a little for the mag boot.
I think I'll just use the generic boots. They have plenty of rubber on the bottom for an easy fit. 

MK2 - 3mm screw in the top of the switch to correct the low height but retain the plate on top for the generic rubber boot. The plate is 3.1mm below the top of the the top of the switch housing.






Generic boot sitting in place. I think about 0.1 - 0.2 mm higher would be perfect for the generic boot , for the mag boot I think same plate postion , install the complete switch in the mag tube , then fit a small ring / washer / mark position where you will install ring / washer as the mag boot will need a very accurate support.






Can anyone tell me the thread size of the Mag grub screw in the stock switch?


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## Chodes (Oct 19, 2008)

Too easy!
This small plate works great with the stock mag rubber boot.
Now for my MK4 with internal securing screw.


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## LuxLuthor (Oct 20, 2008)

Nice job, Chodes. I can imagine how much time this took you including all the little details.  I was able to fit the Judco in a stock Mag D switch after dremelling out a bit of the blue plastic piece & adding 3M #2229 Mastic Tape, then just needed to ground/anchor KIU on top of switch & solder other lead to bottom of Mag switch spring.


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## Chodes (Oct 20, 2008)

Thanks Lux. I've checked out fitting a judco in a mag switch , I'm getting quicker at producing these now though now I'm glad to say.

I'm clearly not a talented designer , I finally came up with an obvious good design, should have been obvious from the start...
I present the MK4! 
Not finished yet , got to add a few bits but the main design improvement is done : a 6mm thick aluminium to connect front and back and support the base of the switch and connect front and back of housing. The fibreglass plate on top is a firm fit under the spacers. It does not need to be attached to anything but the Judco shaft ,it can't move anywhere.
The aluminium plate will allow an internal securing screw as per stock mag (blue circle is will be a hole for scre driver / hex key.
I'll fit a Kui kit as per the MK3 switch.
A top plate with rubber boot support will be made as per MK3 switch , but again will not be fixed - just held in place front and back by the end plates , and made wide enough so it just fits inside the mag tube and won't be able to move sideways.
Not a drop of JB weld anywhere :twothumbs 

With a short shaft Judco (these are long shaft switches remember) I should be able to squeeze a FET / NTC in there.
This back of this switch will sit approx 10mm forward in the body than a stock mag switch. That should be just enough to allow 3 AW C LIONs to fit in a stock Mag 2D tube.(Mag 85)
If using an external securing screw I could get 20mm extra space inside the tube using single end plates rather than double.
Alternatively switch could be lengthened to fit NTC/FET / other electronics a nice distance away from the heat of the bulb.

I really feel like this has been worth the effort now.

The MK4:


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## rolltide (Oct 24, 2008)

Chodes,
I really appreciate you posting this thread and all the pics. I want to make some high temp switches for some of my hotwires and you have given me a lot of good ideas.

Thanks again


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## Chodes (Oct 24, 2008)

rolltide said:


> Chodes,
> I really appreciate you posting this thread and all the pics. I want to make some high temp switches for some of my hotwires and you have given me a lot of good ideas.
> 
> Thanks again



You're most welcome. Makes me happy to think the thread will be of some use.


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## lctorana (Oct 25, 2008)

Chodes said:


> ...happy to think the thread will be of some use.


 
Very much so. The more so because this switch assembly helps not just M*glites, but ANY torch with a side-clicky switch arrangement. With room to spare for a NTC, FET or even a mini relay.


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## LuxLuthor (Oct 25, 2008)

Chodes, here is the shorter stem Judco inside the stock switch....in this one I put the black part of switch on back side, and used the Mastic tape as filler. Just another option.


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## flex76italy (Oct 25, 2008)

Lux, where is the GND path? :thinking:


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## X_Marine (Oct 25, 2008)

Great job Chodes, thanks for sharing and enticing others to share as well.. :twothumbs

Really good stuff all!.

Thanks
X/BillyD..


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## Chodes (Oct 25, 2008)

No worries Billy. It'll be interesting to see what other people build.

Wondering where Lux's ground path is too. Suspect it will be associated with the securing screw. Wondering what that (I assume is) a heatshield
is too.
I realised when looking at fitting a Judco in the stock mag switch that it would be hard to take advantage of the inbuilt "boot platform" - the top part of the switch that supports the rubber boot if using an internal securing screw.
I've got my internal screw in the MK4 switch, I'll post pics of the complete switch once it's done. The button will have to be slightly offset to allow room for an allen key but not too much.
I'll have to change the design a little when I get some short shaft Judcos - will use same 6mm plate top and bottom.


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## LuxLuthor (Oct 25, 2008)

I soldered one Judco lead to KIU using Aluminum solder. Another, I soldered a small anchoring eyelet to Judgo lead and secured with extra nut inside KIU pedestal anchoring screw. Then grounded KIU to body 1 of at least 4 ways I have tried. 1) Used anchoring spring clip on bottom of Mag switch, then pushed a wedge of conducting metal in gap between top KIU and Mag body. 

2) Small Set screw (4/40 size & correlated drill bit & tap threads) through outside of mag body. Quick, easy, and tiny set screw hole barely noticeable which you can dab over with close matching model paint if you want. 

3) Invert KIU and use longer bulb pedestal legs. Now can anchor set screw (drill and tap side of KIU) from inside KIU against Mag body.

4) KIU back to normal upright, drill/tap set screw hole near edge of top KIU surface, but angle down/outside at 45° angle, and put another on opposite side. Now set screws are hidden inside and angle down and towards side.​I always use pointed SS set screws. Taps are very easy to use because Aluminum is so soft. Yeah, that white circle is a piece of Fiberfrax from Aircraft-Spruce.


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## Chodes (Oct 25, 2008)

Thanks Lux.
I'm happy with an external screw for most lights. 
With the Kui kit , if using an external set screw into the Kui disc, it should be possible to conceal the screw under the Mag head depending on the head position.

Here's the offset required for my internal screw - 










It's captive - the top fibreglass plate stops the screw from being wound out too much. 
I think it would be possible to angle the screw slightly to allow the switch to be centered better, not sure if it would try to push the switch backwards.


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## N10 (Oct 27, 2008)

very nicee...and ingenious!!! i was just wandering if that switch still retains the "water resistance" that the original rubber cover offers..because the original mag switch has some kind of "lip" that gets some pressure around the edge of the rubber switch cover...keep up the excellent workk!!


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## ^^Nova^^ (Jul 28, 2009)

Wow, awesome stuff.

I may have to borrow your design to make a switch replacement to use with the new regulators that are available. Just need to find a small momentary push button switch to use.

Cheers,
Nova


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## paetzi (Dec 14, 2009)

Is anybody out there that can build me a switch like this with a 100k Ohm pot that´s also an switch like this one?
http://www.conrad.de/goto.php?artikel=445878


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