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#1

BigWave
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From: Melbourne
Joined: 19 January 2016
Posts: 4,693
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10 January 2020 09:00 pm

I have now seen quite a few beautiful Fluorescent mineral collections, and have now started collecting some mysely as a secondary hobby to gold prospecting.

I recently traveled to the Beltana mine in SA to find some rare fluorescent Willemite (good samples sell to collectors for good bucks), but one of the major barriers to entry into this interesting hobby, is the cost of Ultra Violet (UV) torches and lamps.

High efficiency LEDs have been developed to cover visible and InfraRed light bands, but have only recently started to become available in the lower energy UV band (UVA).

Visible light starts at around 400nm for violet and ends around 750 for deep red as shown below:
1578647387_light.jpg

Within the UV band, there are 3 sub-bands (equivalent to different "colours"), including:
UVA, or near UV (315–400 nm)
UVB, or middle UV (280–315 nm)
UVC, or far UV (100–280 nm)

As shown in the above picture, the light's photon energy increases with decreasing wavelength (or increasing frequency). We all know that X-Rays have much higher photon energy than visible light, as they'll penetrate many materials including flesh.

With recent advances in semiconductor technology, Long Wave UV (UVA) LEDs have now been developed with reasonable efficiency (UV Output / Total Power Input) to around 25%.

Modern torches using these LEDs emit a narrow UVA light spectrum peak just outside of our visible spectrum with a wavelength of around 365nm.
Some critters can see this light.
Some relatively low cost torches using these LEDs are now available, including the Convoy S2+ (around AU$40 excluding battery) which use a 4W LED made by Nichia (I reckon the Nichia LED is about the best UVA LED available at this time).

The Convoy S2+ also produces a small spill-over amount of violet light light which detracts lightly from the beauty of minerals which glow under UVA light.

At this time, I have not seen torches that are better than those using the Nichia LED, although Convoy also make one (FyrFly) with an LG LED which is supposed to be very similar, but which apparently gives off more violet light. You can buy cheap after-market filters to reduce this spill-over visible light. I have installed one in my Convoy S2+ which further enhances its display characteristics.

Don't even consider using "BlackLight" torches which peak at 395nm as they give off way too much visible light, and are nearly useless.

Whilst around 15% of minerals will fluoresce under UV light, many more do under the shorter wavelength UVB and UVC lights than do with UVA torches.

LEDS with reasonable efficiency are not yet available in the UVB or UVC bands, so hobbyists use mercury vapour lamps with expensive filters to generate this light.

So, unless you have big bucks ($500+ for even moderately powered vamps) this is where home builds starts, but be careful, as these shorter wavelength lamps are hazardous to eyes and skin, and must be treated with great respect. Attached below is a short article on these hazards:

"Short-wave UV, with wavelengths around 250 nm, excites fluorescence in a whole different set of minerals. The lamps are much more expensive, though. Moreover, the light itself is hazardous.
Short-wave UV causes skin burns and eye damage. Although all light is technically radiation, this stuff is really radiation. Short-wave UV is what’s used in sterilizing lamps and UV water purifiers. (The sun’s short-wave UV radiation is filtered out by the ozone layer, high in the stratosphere although UVA and UVB will penetrate, causing sunburn and cancers.)
These factors make short-wave UV fluorescence a minority hobby.
"

Welders will also produce UVB and UVC light, and I have met many with nasty "sun burns" from excess usage without covering skin.
Always use eye and skin protection when using UVB and UVC lights, and NEVER look directly at the lights.

Whilst I have a low-powered UVB & UVC lamps (as well as a Convoy S2+ UVA torch) (I used these searching the Beltana mine for Willemite at night), LoneWolf and I plan to make some far stronger for a fraction of the cost than they can be bought for - generally from the States. These will be used for fluorescent mineral displays (in appropriate acrylic or glass display cases which stop the dangerous UV light escaping).

I have ordered some basic parts (lamp and ballast), and when they arrive, if there's any interest, I'll start to detail the build.

We look forward to hearing from other fluorescent mineral enthusiasts.

Last edited by BigWave (10 January 2020 09:23 pm)


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#2

RM Outback
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10 January 2020 09:44 pm

Very interesting BigWave thanks for the detailed explanation and hazards thumbsup I'm looking forward to learning more about this interesting topic.

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#3

Detectist
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Joined: 20 June 2013
Posts: 569
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10 January 2020 11:41 pm

Hi BW

I have a Convoy C8 (365nm) but unused in the field yet. I made enquiries in the USA for a 9w SW unit but it appears quite costly and they would have to modify for Australian recharging (ie 240v). I was told that a 9w (minimum necessary I was told) would give me a 2 metre range. If you guys can put one together (better?) for a reasonable cost I would be interested.

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#4

Ded Driver
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From: West of the Border, WA
Joined: 27 May 2018
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11 January 2020 01:12 am

I too am very interested to see the fruits of your labour ... both build & final results on mineral samples thumbsup


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#5

Tathradj
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From: Now in Bega, NSW
Joined: 17 February 2014
Posts: 10,461
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11 January 2020 08:30 am

I recently bought a 365nm torch to set the glue for my phone screen replacement.
I will delve into it later as it is in workshop in Bega.


A couple of HiBankers inc. accessories, , QED, 4500, SDC2300, Gt1600,
Aldi, A Prado 4x4, A'Van Cruiseliner and a heck of a lot of determination.
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#6

10fp
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From: Adelaide
Joined: 16 December 2015
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11 January 2020 06:29 pm

carefull , start discovering the world of flashlights at http://budgetlightforum.com/ and you may get hooked badly ,,,, i did a few years ago , so hav lots of lights now

just recently got a Sofirn SF32 uv 365 for $26 aud at Banggood


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#7

LoneWolf
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From: Gold Coast, QLD
Joined: 12 April 2016
Posts: 4,891
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11 January 2020 06:41 pm

10ft, Its not a True UV light... Its a 'Black Light'.... Won't work on most Minerals that Fluorescence... Good for checking money and looking for Scorpions tho...

LW....


Growing Old is Inevitable.... Growing Up is Optional.... Union Proud and Union Strong... A.M.W.U Active Member....

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#8

LoneWolf
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From: Gold Coast, QLD
Joined: 12 April 2016
Posts: 4,891
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11 January 2020 08:17 pm

Oops sorry I got your output of your torch as a 395... My mistake... ops

LW...


Growing Old is Inevitable.... Growing Up is Optional.... Union Proud and Union Strong... A.M.W.U Active Member....

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#9

BigWave
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From: Melbourne
Joined: 19 January 2016
Posts: 4,693
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11 January 2020 10:23 pm

The first UVC lamp that I'm going to build will use the Philips PL-S13/UV/G23 (cost $37.40 ea).
This is a sterliisation lamp (germicidal), and should be treated with caution!

This lamp is similar to most fluro lamps, but you can see that it doesn't have the white phosphor inner coating which normally absorbs the UVC and gives off visible light. Without the inner phosphor coating and having a quartz rather than glass tube, this unit transmits the UVC light (along with some visible light which must be filtered out (refer below).

It is a 13W lamp, that will give off around 3.5W of UVC, and uses a common 2 pin G23 lamp holder (~$1 ea).

This lamp has a "starter inside its base, so only requires the 2 pins.
1578740091_philips_pl-s13-uv-g23.jpg

To drive this lamp requires a cheap G23 lamp holder which connects the 240V mains by way of a serial 240Vac 13W "ballast".

These "ballast" units provide the high voltage to start the arc, then a reduced voltage when the lamp's arc is stable. Apart from a power switch, wiring and a cheap cooling fan, that's all for the circuitry.

The ballast that I've chosen is a simple magnetic one ($12 ea) as shown:
1578740584_ballast.jpg

I'll bung these in an aluminium box, with a long slot cut to let out the UV. I'll put a polished Aluminium reflector behind it (probably Alfoil coating a section of PVC pipe halved lengthways), to concentrate light through the slot which will be covered with a Hoya U-325C UV bandpass filter glass (that's probably as expensive as all the rest of the components). This filter gets rid of the visible light.

Add the electronics fan, some rubber feet and a handle, and that should do it for my first home-made UVC lamp (I reckon all up around $230 in parts).

Of the 3.5W of UVC output from the lamp, I expect 80% to make it to the filter (with a good reflector) and a 60% transfer through the filter, giving a UVC light output of around 1.7W. This is far better than the few mW given off by today's best UVC LEDs!

Electrical parts are on order, so should be able to start the build in a week or so. Will post some pics of its progress......

Last edited by BigWave (11 January 2020 11:21 pm)


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#10

BigWave
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From: Melbourne
Joined: 19 January 2016
Posts: 4,693
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19 January 2020 04:03 pm

The lamp (13W UVC) and matching ballast have arrived, so I strung them together for a quick test (was wearing protective glasses):1579410095_ballast_amp_light.jpg:
Cheap but sturdy Aluminium case and ZWB1 Filter (150mm * 50mm) on order, so should be ready to start building shortly.

Last edited by BigWave (19 January 2020 04:04 pm)


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#11

Guessologist
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Joined: 06 February 2018
Posts: 312
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21 January 2020 11:54 am

I think I'm going to have to dust off my lamp and start photographing some of my collection properly now that this subforum is here, finding fluorescent minerals used to be my jam. I thought about building a SW UV lamp from one of those Makita battery powered fluorescent torches but it never really got off the ground.

One of those would have a weight and portability advantage over the expensive US made lamps, I have a Way Too Cool 18W UVA/C lamp which is great but uses a 12V supply, I've got a lead-acid battery for it but it's really too heavy for 2020 and I should get something lighter.

Come on shortwave UV LEDs, where are you?


Equinox 600 / E-TRAC / White's GMT. Combined age of predecimals found so far: ~33,350 years (294)

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#12

BigWave
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From: Melbourne
Joined: 19 January 2016
Posts: 4,693
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21 January 2020 12:45 pm

Hi Guessologist, you could get a 240/12V power supply for your light to run directly from mains?
I think shortwave UV LEDs are a long way off sad


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#13

Guessologist
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Joined: 06 February 2018
Posts: 312
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21 January 2020 02:09 pm

Could do if I wanted to set up a display with it (which I do eventually) but thinking more for the field, something light that I can just velcro to the side of the box and have it run for a couple of hours. The current battery is alright for home for now.

Here's the lamp I was thinking of butchering, got the idea from a forum somewhere:

1579575421_mak.jpg

Just drop a 13W shortwave bulb in, design a decent reflector and chuck some filter glass on the front was the gist I think, reasonably powerful field lamp for not huge dollars although as you said the price of the filter is pretty gross.


Equinox 600 / E-TRAC / White's GMT. Combined age of predecimals found so far: ~33,350 years (294)

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#14

BigWave
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From: Melbourne
Joined: 19 January 2016
Posts: 4,693
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02 February 2020 08:30 pm

Have started building my first UVC lamp running from 240Vac.
Uses an IEC power cord inlet with 1A fuse.
1580635731_outline.jpg
Inserting the bits:
1580635016_fitting_parts.jpg
Then gluing in the optical UVC bandpass filter:
1580635062_optical_filter.jpg
Now just have to add the internal reflector (0.5mm Aluminium sheet polished with Mothers Aluminium Polish); screw it all together; wire it up, and Bob's your auntie.
Way cheaper (1/4 the cost) than buying from the USA and suited for 240Vac.
Will hopefully post a few more pics of the completed unit this week.
.

Last edited by BigWave (02 February 2020 09:25 pm)


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#15

BigWave
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From: Melbourne
Joined: 19 January 2016
Posts: 4,693
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09 February 2020 07:43 pm

Have been distracted recently cleaning up storm damage, (much chainsawing), but finished the reflector today:
1581237571_reflector.jpg
0.5mm Aluminium sheet polished nicely with Mothers Aluminium polish.
The spacers fit the reflector to the width of the optical filter for maximum UVC output.
I'll hopefully finish the build tomorrow for a heat trial.
It doesn't have a fan, but the ballast will be heat sunk to the casing, so should be OK.

Last edited by BigWave (09 February 2020 08:25 pm)


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#16

just starting
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Joined: 28 December 2018
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09 February 2020 08:00 pm

I just finished watching the new Abandoned mines video on fluro minerals in a mine that they uploaded this morning.
https://www.youtube.com/watch?v=zLyFV2S … ploademail

Last edited by just starting (09 February 2020 08:01 pm)

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#17

Detectist
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Posts: 569
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09 February 2020 08:20 pm

BigWave wrote:

Have been distracted recently cleaning up storm damage, but finished the reflector today:
Aluminium sheet polished nicely with Mothers Aluminium polish.
I'll hopefully finish the build tomorrow for a heat trial.
It doesn't have a fan, but the ballast will be heat sunk to the casing, so should be OK.

Well done BW. I hope the storm damage wasn't too bad.

When people post their skills like this I am always wondering how ... I have 2 hands full of left thumbs. Great work.

On another matter, i dug out some bought fluro-ready specimens but have yet to use my UV torch and post pics. Must get around to that.

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#18

Guessologist
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Joined: 06 February 2018
Posts: 312
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10 February 2020 07:24 am

BigWave wrote:

It doesn't have a fan, but the ballast will be heat sunk to the casing, so should be OK.

It would be interesting to see if performance was changed at all in a meaningful way later on with the use of a fan regardless of heat issues. Some/many bulbs create ozone which strongly absorbs UV-C so it's best to vent it out if it's in there. I guess a sniff test would tell you if a lot of ozone being made.


Equinox 600 / E-TRAC / White's GMT. Combined age of predecimals found so far: ~33,350 years (294)

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#19

LoneWolf
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From: Gold Coast, QLD
Joined: 12 April 2016
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10 February 2020 11:16 am

Interesting Guessologist, I didn't realise they could produce Ozone....

LW...


Growing Old is Inevitable.... Growing Up is Optional.... Union Proud and Union Strong... A.M.W.U Active Member....

#20

BigWave
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From: Melbourne
Joined: 19 January 2016
Posts: 4,693
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10 February 2020 11:34 am

Guessologist wrote:

It would be interesting to see if performance was changed at all in a meaningful way later on with the use of a fan regardless of heat issues. Some/many bulbs create ozone which strongly absorbs UV-C so it's best to vent it out if it's in there. I guess a sniff test would tell you if a lot of ozone being made.

The UVC lamp that I'm using has a wavelength of 254nm. The quartz prevents shorter wavelength UV being transmitted.

I have read that a wavelength of 220nm or shorter is required to form ozone (viz: 185nm used by many ozone producing lamps), so this lamp should be OK.

Last edited by BigWave (10 February 2020 11:52 am)


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#21

goldierocks
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Joined: 10 January 2015
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Robert Benchley...
I have kleptomania, but when it gets bad, I take something for it.

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#22

LoneWolf
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From: Gold Coast, QLD
Joined: 12 April 2016
Posts: 4,891
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10 February 2020 02:07 pm

Not a bad price, but a bit low on wattage... I looked at some other items on that site... OMG their prices are up there... yikes

LW...


Growing Old is Inevitable.... Growing Up is Optional.... Union Proud and Union Strong... A.M.W.U Active Member....

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#23

BigWave
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From: Melbourne
Joined: 19 January 2016
Posts: 4,693
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10 February 2020 07:45 pm

Thanks GR - I've searched the net for UV lamps and have bought a few, then decided to build my own.
I'm building one powered by 240Vac, as I want to use it on a display case.
It therefore has to be a much higher wattage and not running on batteries.
It'll cost around $130 in parts and I'm having fun building it (when I find time).


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#24

sand surfer
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From: bundaberg, QLD
Joined: 21 April 2016
Posts: 920
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11 February 2020 11:21 am

Here is the torch LW1581380388_thumbnail_2.jpg1581380407_thumbnail.jpg
white light1581380440_thumbnail_1.jpg
yellow light1581380468_thumbnail_3.jpg
uv light1581380504_thumbnail_4.jpg
white and yellow light pictures taken outside in the sunlight rector burners they are that bright, uv in the shed could not see the uv outside

Last edited by sand surfer (11 February 2020 11:27 am)


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#25

goldierocks
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Joined: 10 January 2015
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11 February 2020 12:46 pm

BigWave wrote:

Thanks GR - I've searched the net for UV lamps and have bought a few, then decided to build my own.
I'm building one powered by 240Vac, as I want to use it on a display case.
It therefore has to be a much higher wattage and not running on batteries.
It'll cost around $130 in parts and I'm having fun building it (when I find time).

Mains is good for display but not for use in the field - horses for courses I guess.


Robert Benchley...
I have kleptomania, but when it gets bad, I take something for it.


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