Fulton Angle-Head Military Flashlight mods?

I tested 70% isopropyl alcohol for insulation. I got 0.1 mA at 4.1 V with some salt sprinkled in and no measurable current without it. On the ohm meter, I got 100 K ohm with salt and 1 M ohm without it. I don’t trust the ohm meter for this because I don’t think it uses realistic voltages on these scales. So 70% isopropyl is marginal, after it picks up ions from other components, but 90% should do. Methyl alcohol is more polar and might hold more ions, but I could get it dryer and it might cool better.
Alcohols boil at less than 100 C, which is in the operating range for leds, so we might get streams of bubbles like in a Cray II. This would work even better if the led were de-domed, but I don’t plan to go that far. I am not that big on military angled flashlights and hope to try it with a regular $3 2D cheepo. The Crays used freon. It may have better thermal properties, but probably the main reason is that they consumed a lot of power, so flammable liquids would be a fire hazard. An led will burn out long before it gets hot enough to start a fire. If one used Li batteries and they burned up, the liquid might add to the fire hazard, or if it spilled in the presence of a flame.

I’m sure the very similar, brit version was made by Crompton, it didn’t have the switch guard though, and had a set of red/green lenses in the bottom as well as a spare bulb, I may still have one somewhere.

Petrol doesn’t explode, just burns, and only when the ratio is 9-18% meth/eth/prop/but/pent/hex/hept/oct/non-ane and the rest air. Oh god my organic chemistry is coming back to me now…

Anyway if the pressure builds until it leaks, then it is possible it will burn if there is a source of ignition such as a spark or an open flame, or it can auto ignite if it’s like 600 degrees celcius+.

It can’t get that hot. The only danger I can think of is that the case leaks or brakes from handling or dropping. Maybe that would argue for using a military version that is tough. At least it is no more dangerous than when they used to store alcohol in glass bottles.

Added: The thermal situation will be that it is about 85 degrees C around the led, what XM-Ls are rated at I think, and close to the boiling point of alcohol. Whether or not it boils, the alcohol will expand with the temperature enough to circulate and spread the heat at least around the plastic reflector and window (lens) and to some extent around the whole flashlight. The plastic case is very large area and thin, so the heat is conducted to the outside with good efficiency. It is then carried away, just like it is with an Al light. Clearly it won’t boil enough to increase the pressure significantly. The case will expand at a similar rate to the alcohol, and the case is flexible, so the pressure won’t vary much.
If it boils, it will be a tiny stream of tiny bubbles as with the Cray II I saw.

For my 4 D cell light with good Rayovac alkaline cells I get 5.25 A across the battery pack with a meter that I think has around half an ohm in the leads. The cells are a little over 1.5 V each. So it would take about 4 cells to drive an XM-L at a little under its rated 3 A. That is half of the 5 or 6 amps and half of the 6 volts. That would be direct drive, but a driver could not improve on it much, because that is about their maximum power output. A 2 D cell light needs a driver to drive the XM-L at half power, with alkaline cells.

I plan to start with the parts from the light I am cannibalizing, but may try these if all else works.
That leaves out the question of more conducive glue.

The army surplus store has Fulton angle heads for $30 or 40. At the drugstore I got two Eveready lights for $3.60. These are identical to my old orange one except already converted to led with a drop in bulb and a step in each of the 5 internal ribs to hold only one D cell. Each came with one Eveready Super Heavy Duty dry cell. The spring and side current path are steel. The part that moves as the switch appears to be copper plated. It contacts a steel plate that holds the bulb.
Clearly I can’t use any electrical part, but the body and bezel seem sturdy and the reflector looks good and throws a tight spot almost as small as my old one does. I am testing what adhesives will stick to the body.
After thinking, I came up with a better name for this entry.

One of my first custom builds, I used 32 5mm LED’s wired in series
Direct drive off D alkalines, I ran it non stop for 230 hours when I screwed up and Turned off my phone (that I was timing it with). It never dimmed, I stopped the test and put in a new set of batteries and to my eyes it looked exactly the same brightness as when I stopped the test, I would put money in it lasting >500 hours on a fresh pair of alkalines! I don’t use it, ever, but its in one of my vehicles somewhere, I think maybe the horse trailer, the only thing that worries me now that I think about it is the alkalines leaking, maybe time to upgrade to some LSD NiMH D’s or even just L91’s in adapters.

Since I am not using an angle head, I started a new thread for my liquid cooling experiment, Liquid cooled XM-L Eveready 2D sleeper, here Liquid cooled XM-L Eveready 2D sleeper .

Don’t you mean parallel? That would take a lot of D cells.

I think isopropyl alcohol lights with a match because the heat vaporizes it but its flash point is higher than room temperature. The ignition temperature and heat produced are probably between those of gasoline and methyl alcohol.
The led is nowhere near the ignition temperature nor can I imagine any way to light alcohol with a malfunction of the 3 volt electric circuit, so there would have to be an outside source of ignition for it to burn.
Anyway, there are only a couple of ounces of it so there is no danger if I see it. Making it safe for mass market is a different question but will be solved if liquid cooling turns out to be useful.

Added: It appears that the diode itself may fail by becoming more conducting. The runaway current is limited by the copper leads melting. Their melting point is above the ignition temperature, but like 3 volt inductive sparks their size is too small to cause sustained combustion.

It was a few years ago so I took it apart to check, its 4s8p

I bought a 3 watt 1-3V. PR_based led bulb from Superbrightleds.com. $17 and change, shipped. Sorry I can’t post photos. I put new battteries in the Fulton…about 4X brighter than the original incand. bulb, and about twice as bright as the no-name bulb I bought about 6-7 years ago, with a better tint. it lights up the back yard in fine fashion, and would be great for car, camping, walking the dog, or any other general-purpose thing you might wish to do. Don’t know about run time, but the other bulb ran a good year on the last set of batteries.

When I compared the cost of buying a soldering tool, the components, and the time and aggro of building the mod, no contest. If you have a light that uses PR base bulbs, this just might be what you are looking for.

Would I love to have one of Elektrolumens’ AngleLux lights? O my yes, but economics being what they are, not likely. 8)

Nitroz wrote:

Found this site when I was trying to find a fix for my Fulton which does not work.

Switched the bulb and batteries and still does not work.

Hate the throw away a prefectly good light.

Can anyone repair it?

am more than willing to pay for the repair.

The contacts may be corroded. My 1929 RAY-O-VAC started working when I worked the switch, where things screw together and the tail spring back and forth to rub off corrosion and dirt. Anything that is not gold plated corrodes on the surface.

I have an issue light that crapped out. I ordered an led replacement light from Rothco. When it got here I noticed the new light was cheap compared to the issue light.
So I pulled the led head out and stuck it into the Army light. All I had to do to make it work was bend the switch arm inward a bit to make contact with the new led dropin.
That thing runs for days straight on new batteries and has multi color options for signaling and night vision and map reading.

Oh wow...forgot those bulbs were flanged

these will work

These also work as good replacement for 1-4 cell maglite (or other flanged type incandescent bulb flashlights) and they have a high voltage version that works very well in those hand held 18vdc rechargeable toolkit lights without getting insanely hot

An older thread, but was of interest to me as I have one of these flashlights and have been thinking about putting in one of those Nite Ize 55 lumen upgrades. I did this to two of my Maglites and I liked it quite a bit. Decent output (more than the incandescent they replaced and longer run time). Any issue with doing this to these angle-head lights?

You might get an ugly beam pattern because of the way the led is set further back in the reflector that the filament of the incandescent.

Hey guys, I’m still loving this old flashlight, been doing some searching through the threads… So I got a hold of a couple old Fultons and was wondering if anyone has successfully taken apart the switch and remounted it? If so, can you please explain how it’s done and also post pictures of how it’s done if possible?