Help/advice needed for diy UV light for Amber searching

[djozz]

For 400nm light (and other uv-lights) I have (my brand is Bollé) safety goggles with amber coloured glasses, it blocks uv and gets rid of most purple/blue, but still the glasses are only slightly coloured so you don't loose much light. Similar to this one:

[Hestbech]

Lol! - will save the marriage proposal for my girlfriend then
Yes the return address will do just fine.

So it looks a bit amateuristic with the tape

Looks fantastic! I’ll make sure to keep my hands of the tape. Time, tear and wear just makes it authentic. Kind of like collecting amber. You find a piece, and your imagination wanders. Well mine does anyway. Hell, it was once a “living thing” (originating from a tree) 40 million years ago. And I’m the first human EVER to pick it up. The last thing it “saw” could have been a T-rex! -or a mosquito. Have a couple of pieces containing insects myself (not collected by me though)

Confusius -that could possibly be true! -that would make the claims that amber is fluorescent from 320-380nm even more puzzling.

But thanks to djozz’ tests and this page (I really hope Bob who took the images drops by this thread), I think we are closing in on THE truth about amber. The Goldilocks zone must be somewhere between 365-400nm

[Hestbech]

djozz I’ve got bot a pair of Oakley M-frame with yellow and clear lenses. And a pair of yellow tinted safety glasses from the danish army. So I’m ready for battle

The safety glasses might actually be a good idea, as unexploded mines from WW2 from time to time appears in the areas where I go amber-hunting :-p

[ImA4Wheelr]

Thanks for the info an link Hestbech.

[alpg88]

@Jubeldum

As for mounting a LZ1 on DTP copper, djozz is a master at modding a MCPCB. Doing something like this is like childs play to him.

nope, lz1, just like the rest of ledengin leds, have totaly different foot print, you can’t mod xml\xpg star for it. why even bother, they are sold mounted on correct stars.

[Jubeldum]

@alpg88

@Jubeldum

As for mounting a LZ1 on DTP copper, djozz is a master at modding a MCPCB. Doing something like this is like childs play to him.

nope, lz1, just like the rest of ledengin leds, have totaly different foot print, you can’t mod xml\xpg star for it. why even bother, they are sold mounted on correct stars.

Is that so? So you are saying there is no way to be able to modify a XML or XML Color MCPCB to mount a LZ1 so you can have DTP?
https://budgetlightforum.com/t/-/24011?page=2#comment-674651

Is it also impossible to modify a XML MCPCB to be a XML Color MCPCB?
https://budgetlightforum.com/t/-/26139

[Hestbech]

Nice mods

I got a reply from Bob who took the pictures linked to earlier:

@Robert Fosbury

I have a number of other observations of amber. Try looking at: Search: amber | Flickr.

I will look at your thread and give you a considered answer a bit later. My immediate answer would be to use an LED-based (flashlight) lamp around 365 - 380nm BUT you have to add a visible-blocking filter to remove any residual visible light since these LEDs have a long tail of emission spreading over the visible spectrum. I use a Schott UG2 glass filter which works perfectly. I got a whole set of these flashlights from one of my PhD students from China where he can buy them for almost nothing - they sell them for searching houses for pet urine!

More later.

…

Me: Amazing images! I’m trying to figure out your graphs. Will have to do some research on that

The plots I post on flickr are of two types:

1. Fluoresence - these show the power per unit wavelength emitted from the material when it is illuminated by an excitation source (usually UV)

2. Transmission - these show the fraction of the incoming light transmitted by the sample at each wavelength (unitless)

Baltic amber generally fluoresces a pale ‘powder’ blue. The fluorescence is emitted at the surface and looks like a fine coating of blue dust. The best way of seeing this is to use the type of LED lamp I mentioned in my last email. There is no particular point in trying to get LEDs at shorter wavelengths: they emit much less power, they are expensive and they have short lifetimes. 365-380nm is fine as long as you block the visible light with a filter as I suggested.

Me: I recently started collecting amber at the western coast of Denmark. So any tips on the wavelength would be fantastic.

Blue amber - from the Dominican Republic or from Sumatra has different fluorescence properties and is very interesting for a number of reasons which are explained in my flickr posts.

All the best, Bob

[alpg88]

rgbw star is different, the one i responed to was not rgbw star, was it?

[Jubeldum]

@alpg88

rgbw star is different, the one i responed to was not rgbw star, was it?

So you are saying that cutting the traces on a XML MCPCB something like this (I’m horrible at drawing with a mouse) because of the thermal slug encroaching is impossible? Please explain.

[keltex78]

Do the Carlco optics block UV? I think a UV-triple Convoy-S2 would be a good hunting light if the UV isn't blocked. I'm considering options to make a simple reflector-based triple, but I'm not aware of any suitably budget-priced host options.

[Hestbech]

Unfortunately the block all uv. They are made of polycarbonate

• well I’m not sure they all are -if any are made from glass, they do not block uv

[djozz]

I think that plastic flashlight lenses and optics may be made of polycarbonate (PC) or polymethylmetacrylaat (PMMA). A quick search gave conflicting transmission curves for PC, the first one shown is wrong between 300 and 400 nm and seems to have swapped PMMA and PC (it is an advert for a substance called zeonex, so don't trust that stuff!), the rest mostly agree:

But how's that in a flashlight situation? I positioned three flashlight optics in front of a white piece of copier paper and directed a single colour flashlight to them from 50cm distance so that a shadow was cast on the paper. The UV flashlights cause blue fluorescence on the paper so that it shows visible. left=standard plastic aspheric lens (PMMA or PC?), right=glass aspheric lens, bottom=Carclo optic (PC).

First in 532nm:

good transmittance for all three

Then 400nm:

the plastic optics seem to absorb some of the light, but you get away with plastic

And 365nm:

so don't use plastic for 365nm, glass is fine.

[keltex78]

Wow! Thanks djozz! I know I won't waste my time trying to make a TIR-based UV light now...

[Hestbech]

Nice and understandable explained!

[alpg88]

@Jubeldum

@alpg88

rgbw star is different, the one i responed to was not rgbw star, was it?

So you are saying that cutting the traces on a XML MCPCB something like this (I’m horrible at drawing with a mouse) because of the thermal slug encroaching is impossible? Please explain.

yea, that is what i was thinking, the heatpad will short the contacs, but looking more at your pic. it does seem like it can be done, after all. at least in thoeory, my bad, seems like i was wrong here.

[alpg88]

@Hestbech

Unfortunately the block all uv. They are made of polycarbonate

• well I’m not sure they all are -if any are made from glass, they do not block uv

yes, i noticed the problem a while ago, i got good results with PETG instead of polycarbonate, also some scratch resistant coats block uv as well.

also acrilic lets uv thru, but it is too britle, imo. cracks easy. not something i use in my buids, but it can be.

however i have not tested neither petg nor acrilic on how they do\don’t let thru 365nm. the lowest wavelenght i tried was about 375-380nm.

[Hestbech]

Wuhuuu!
Just received my Solarforce L2N host, with a uv-LED 365nm LedEngin p60 drop-in. Happy happy! Though I’m actually more excited about the taped up Ultraforce C8 with a 400nm LED soon to be received from djozz :-p

…

Seems to be an error in the LED - but not noticeable when looking at the hotspot on a wall. (click for large image)

Edit:
Actually it is visible … Will send a mail to http://www.customlites.com/

[djozz]

Wow, that is a serious fault in that led, and clearly visible, they should not have sold you that. For the rest: great purchase!

[Hestbech]

Yeah … I just mailed Dave from customlites to hear what he says.

I’m quite surprised by the amount of visible light this LedEngin LZ1 emits. Will field test it sometime in the coming week. Depends on the weather.

I am still considering if I should buy a UV pass-through filter as Robert suggested earlier. But that depends on what the field test shows.

[Jubeldum]

@djozz

Wow, that is a serious fault in that led, and clearly visible, they should not have sold you that. For the rest: great purchase!

I really wondering if LEDENGIN is having some serious quality control issues. I had to RMA the first one that I bought because the die was shifted up in the 1 o’clock posistion under the lens. And now this one with a bad spot on the die. For the amount that they charge for them, they should be perfect.