Cheap hacks to change throw to flood?

[ahains]

I started biking to work recently, which means it is a bit dark for my ride home (short days in the NW of the USA). A friend pointed me to a 4Sevens quark and I have been using this strapped to my bike helmet. It has been a great light, but I want more light in front of me.

I just received my DX order consisting of 4 flashlights running Cree R2s (and the 18650 batts and charger). These will be handlebar mounted for the most part. I anticipate having plenty of light out front of the bike, but I would really like to add some broad flood light in the ~10 feet in front of the bike. I'm hoping there may be some cheap (free) hacks I can try out to convert one of these cheap DX lights to be pure flood.

It seems to me that my two options are (1) scatter the light at the emitter so my whole spill area receives more light or (2) scatter the light at the lens.

After a few searches I believe the led has a glass dome, which seems more difficult to sand down. It also seems to me that even if I approach a broad bulb style of illumination, there is still going to be a large part of the light caught by the reflector. So my guess is that this will not be a good option.

The lens it comes with is glass. I assume I can just scuff this up with some sandpaper or other abrasive, and get a diffuse flood out the front. It may cost a significant amount of light, I really have no idea. I guess if I hate it, I would just be out one lens

Actually just had another thought while looking at it. When I unscrew the lens and play with it, I see I only barely have to push the LED past the edge of the housing to get a good connection. So it looks like it would be simple to cut off the front ~2/3 of the reflector, and cut off the back ~2/3 of the head. This would put the lens just barely in front of the LED and should be almost pure flood. I guess I would have to cut the reflector down in stages to experiment with the side of the spot.

The current spill area is actually about ideal, I don't suppose there is any simple way to make all the light focus on the current spill area?

 

[KeyGrip]

What is the outer diameter of the Quark's head? And more importantly, do you want this to be reversible?

 

[pmoore]

Before you go hacking and cutting, shearch for some difuser material. This can be applied and removed if you want.

Paul

 

[carbine15]

for more flood spray a light dusting of hairspray over the reflector. For even more flood, remove the reflector altogether.

 

[ducat]

Before destroying the lens try smearing a film of petroleum jelly over the glass and see if that works. Just keep it away from the o rings.
Old photographers trick to get soft focus.

 

[Egsise]

Put "frosty" scotch tape on the lens.

 

[ahains]

Keygroup - to clarify, I am definitely not going to mod the quark. I'm only considering getting goofy with my cheap DX lights
For these, I don't care if it's reversible.

pmoore - good thought. I actually have a big sheet sitting around of some diffusing stuff to put on my garage window, I should cut out a scrap and check it out.

Carbine15 - I was looking at removing the reflector, but from the factory the LED sits quite far back from the lens opening. So a whole lot of light would be lost on the inside of the head. That is why I was considering option (3) from my original mail - reduce that large gap between the LED and the lens.

I had another idea this morning. I have some cheap small plastic magnifying glasses I bought in bulk for my kids and their friends. I'm going to try to find one and see what I get if I hold one of those in front of the flashlight lens.

Ducat - I'll try the vaseline idea.

Egsise -I tried some scotch tape briefly and it did increase the brightness of the spill area, but it looked to be extremely inefficient to my eyes.

 

[alphazeta]

If going the tape route, try a product called

Glad press n seal from the grocery section - It's a film that many of us have used for diffusing the glare of the old riverrock lantern. Evens out any beam immensely

If trying the spray option - I like to use acrylic based frosting spray on the lens. (automotive section)

Both options are readily reversible.

 

[Disco-Dave]

Will the heat the light produces not slightly melt the vaseline until it just drips off ?

 

[T0RN4D0]

Just remove the reflector and you get pure flood. If you don't like it just put the refector back in and search for a new solution.

 

[Linger]

Buy a few ledil Boom's ($4 each), these have an excellent beam for cycling, no artifacts just smooth transition from darkness at beam edge to brighter in the center. Highly recommend these reflectors for near distance especially if you don't want to loose lumens.

Optics are another great option. Medium or flood optics (tiny clear 'cups' that sit inverted over the emitter) are fantastic.

*alternative - shim out the bottom of the reflector - you're trying to get the led to sit below the base of the reflector. An easy way to do this is small strips of electrical tape, building up 5 or 6 layers on right and on left side of reflector and put it back on.
Alternative focus can come from cutting away the bottom of the reflector - the shorter, wider openning version should have a more diffuse spot
(recall- deepest, tightest reflector for tightest focus. Deviating from this should improve flood)

Jump into the cycling forum, lots of talk about beam profiles.
*Dont' try taping magnifying light to lens...there's lots of easier ways that will serve you better in the long run

 

[uk_caver]

If you want a reversible fairly pure flood, you could try making a conical reflector out of silvered plastic film (crisp (UK) or chip(US) packet, etc) of the right size and slope to drop inside the existing reflector.
Cleaning the plastic film before use with hand-dishwashing detergent is fairly easy, and it's worth choosing a piece which isn't creased to cut the reflector from.
A pair of compasses is useful for scratching concentric circles on the film to cut out, and if you make a note of the circle sizes you try, you'll have an idea how big to make them if you don't get the size right on the first pass.

 

[ahains]

I got to try the new flashlight array on my ride home from work yesterday. It was approaching dusk as I left, and completely dark by the time I got home.

Holy cow is that a lot of light. The DX lights appear to be somewhat brighter than the Quark, but not massively so. They spec at 1A versus 700ma, both R2, so no surprises there. IIRC the Quark is like 170 lumens OTF, so I'm riding with a ballpark 900-1000 lumens. The improvement was fantastic, I felt much more confident in some of the faster downhill sections.

I'm pointing the four DX lights in the same general area (the hot spots are spread out a little), so the spill overlaps a lot. Turns out that the spill of 4 of these lights is actually quite bright.
I'm not going to bother with any changes now, the spill is quite usable for a flood area right in front of the bike.
I put some crappy pictures up on my facebook page - http://www.facebook.com/album.php?aid=164758&id=563465989&l=4b8287d7b0
The Quark is helmet mount, so I really doubt I consistently had it in the same spot each time. Gives you a basic idea though. Using SLR, settings identical from one shot to the next.

One of the DX lights is significantly less bright than the others, and seems to be a bit flaky. Sometimes I have to turn the head back and forth to get it to turn on. No big surprises there on the quality level
I'll see if they'll send me a replacement. Not too worried either way since this is after all a Redundant Array of Inexpensive Flashlights

thanks for the tips!
-a

 

[sleepy120]

defusing with white milk bottle containers works for me.

easy to cut, and will bend/mold easily with heat.