PCB UV Box - Follow Up

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Hello,

First off, thank you to every one of you for answering the other thread.
It's given me plenty to research and perhaps over analyse.

I think I'm going to go for the ready kit put together by Rapid, this is
written up below.  But before I do that I'm left wondering something..
Where I have my nails done they use one of the little UV boxes.  They're
here on eBay;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item18%0104409706

Now what I'm wondering is.  Would one of those do the job?  Or more to the
point, would it be cost effective to strip one down and use the parts.
Thereafter ALL you need is an enclosure and some perspex.   Also today it's
become clear regarding 4mm glass that suppliers either only stock
UV-blocking glass, or don't even know at all.  No one knows what they're
selling anymore or even cares!!  This is the UK, it's a dump full of under
achievers and everyone has a degree in Travel & Tourism or Marketing,
everyone else is on state benefits.

So..  The nail box up above?   :-)

Warm thanks,

Alison



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"
Sourcing a UV Exposure Box for PCB Development.
-----------------------------------------------

0. Introduction
1. What's For Sale?
2. Ultraviolet exposure unit with timer 202E
3. Ultraviolet exposure unit with timer 202E - Starter Kit
4. UV tubes available on eBay
5. Flight case style enclosures
6. Minimum parts required
7. Conclusion


0. Introduction
---------------
I wish to start developing PCBs using the Photoresist and UV Development
method.  In the past I have used a Dalo pen and drawn everything out, using
ferric cloride to etch the copper off.  I would like to design more complex
circuits on a PC and print to transparancies.

The immiediate requirement is to source a UV Development box.  There are two
options; Build One; Buy One.  When considering building one the light output
has to be in the range of 400nM.  There is absolutely no point in
approaching DIY outlets as they have haven't a clue what you're talking
about (I've been out hunting today).  Blacklight dark UV tubes for making
your white t-shirt glow are NOT suitable.

UV LEDs have been suggested as a possibility.  These would need to be of a
high candle output documented to be in the region of 5000-7000mcd, these can
only be economically sourced from Hong Kong.  There is a documented concern
that UV LEDs placed in a grid fashion will result in exposure hot spots on
the resulting PCBs.  The projects are documented on the net, yet there are
no examples of the PCBs which have been produced.  This is a natural concern
despite excitement in using such devices.  It would be brilliant to have a
compact UV light box.


1. What's For Sale?
-------------------
There are very few UV boxes out there.  The most basic are about 120 all
in, ranging to 1000's for double sided vaccum models.

There are very many UV tubes for sale on eBay.  UV LEDs are also available.


2. Ultraviolet exposure unit with timer 202E
--------------------------------------------
This is sold by Rapid for 115.68 (98.39+VAT) item number 34-0700.  It is
also sold by Maplin for 105.14 (inc. VAT) item number YA36P.  It uses a
6-minute mechanical timer.  It uses two 8W 12" (304mm) tubes, 15" maybe??.
The exposure area is 240 x 165mm (9.5 x 9.5").  The overall unit dimensions
are 438 x 184 x 102mm (17 x 7 x 4").

http://www.rapidonline.com/productinfo.aspx?tier1=Tools%2c+Fasteners+%26+Pro
duction+Equipment&tier2=PCB+Equipment&tier3=Accessories&tier4=Ultraviolet+ex
posure+unit+with+timer&moduleno29%468

http://www.maplin.co.uk/Search.aspx?criteria=YA36P&DOY=7m4


3. Ultraviolet exposure unit with timer 202E - Starter Kit
----------------------------------------------------------
This is available from Rapid for 129.54 (110.25+VAT) item number 34-0690.
It includes a number of accessories making a saving of about 20 if bought
seperately.  It is Kit B.

These accessories are;

     Rapid    Quantity  Description                     Unit     Sub
(inc.VAT)
     -----    --------  -----------                     ----     ---    ----
-----

    34-0796     (1)     Artwork Drafting Pack           4.95   4.95
                (6)     Assorted Sheet Transfer         -----
    34-0105     (3)     100 x 160mm SS Photo PCB        2.49   7.47
    34-0115     (1)     203 x 114mm SS Photo PCB        3.49   3.49
    34-0295     (1)     Polifix Block                   1.95   1.95
    34-0745     (1)     Polypropylene Chemical Tray     -----
    34-0395     (2)     Developer Crystals              0.79   1.58
    34-0385     (1)     Seno GS Etching Kit             8.95   8.95
                                                              ========
                                                               28.39
(33.36)
                                                              ========

    34-0700     (1)     UV Exposure Unit - 202E                98.39
(115.68)
                                                              ========
                                                              126.78
(148.97)
                                                              ========

A saving of some 20 is made as predicted.  When offset against the
standalone cost of a 202E, the above items are provided for an imaginary
cost of some 10.


4. UV tubes available on eBay
-----------------------------
A wide range of UV tubes are available.  Most are marketed for use with Fly
Killer devices and for curing Acrylic Nails in beauty salons.

4W 6" (152mm) straight tubes;
http://cgi.ebay.co.uk/UV-Fluorescent-Tubes-for-Fly-Killers-4w-6_W0QQitemZ260
104226984QQcategoryZ72361QQrdZ1QQcmdZViewItem

9W 6" (152mm) nail curing double tubes;
http://cgi.ebay.co.uk/4-pcs-x-9-Watt-Bulk-Tube-For-9W-36W-UV-Nail-Lamp-Dryer
_W0QQitemZ220098117777QQcategoryZ67653QQrdZ1QQcmdZViewItem

25W 9" (229mm) U tubes;
http://cgi.ebay.co.uk/UV-Fluorescent-Tubes-for-Fly-Killers-25w-9-U-tube_W0QQ
itemZ260104226614QQcategoryZ72361QQrdZ1QQcmdZViewItem

22W 8" (203mm) Circular tubes;
http://cgi.ebay.co.uk/Replacement-UV-Tube-for-Electric-Fly-Killer-Circluar_W
0QQitemZ320099011789QQcategoryZ72361QQrdZ1QQcmdZViewItem


5. Flight case style enclosures
-------------------------------
It would be intended to fit a self build unit into a small flight case.
These are relatively expensive to buy.  I have a small case here which is
283 x 235 x 90 (11" x 9" x 3.5") external dimensions, it was purchased for
9.99 and contains a hobby drill.  It seems that to obtain the smaller
flight cases it is economically easier to buy something else and to use it's
presentation case, thus discarding it's contents.  Makeup boxes, hairdryers,
all sorts of low priced items come in perfectly adequate aluminium flight
cases.

My full size budget flight case which can be bought for 11 in a local DIY
store has external dimensions of; 464 x 328 x 150mm (18 x 13 x 6").  It is
made as cheaply as possible yet you could not achieve that level of build
yourself without significant outlay.


6. Minimum parts required
-------------------------
This is assuming use of a full size budget flight case, with basic ON/OFF
operation;

              Quantity  Description                     Unit     Sub
(inc.VAT)
              --------  -----------                     ----     ---    ----
-----

                (1)     Flight case                    11.00  11.00
                (4)     12" UV tubes                    5.00  20.00
                (4)     Starters                        1.00   4.00
                (2)     Ballasts                        7.50  15.00
                (1)     Rocker ON/OFF Switch            1.00   1.00
                (1)     IEC 3-pin socket                2.00   2.00
                (1)     4mm Cut glass (local)           5.00   5.00
                (1)     Other unknowns (fixings etc.)  20.00  20.00
                (1)     Travelling costs               15.00  15.00
                                                              ========
                                                               93.00
(NA)
                                                              ========

The above does not take into consideration PCBs, developer etc.  It appears
cost effective to buy the UV 202E kit from Rapid for an approximate 35
extra.  The above also does not take into account stress and rushing about.
I could have the kit on this coming Tuesday after the Easter bank holiday
weekend.

7. Conclusion
-------------
It will be more practical and straightforward to buy the complete kit for
129.54 (110.25+VAT) item number 34-0690, from Rapid.  At this early stage
in my experiences with UV development it makes sense to buy a prepared kit
with instructions where it is all there for you from the moment go.

Having spoken to my Mother who knows everything her comment is, "You're just
like your bloody Grandfather, you'd lick a farthing out of a turd."  In
other words, buy the kit.
"



Re: PCB UV Box - Follow Up
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Now that's just unfair, what about the valuable contribution made to
society by all the meeja studies graduates? I don't work my ass off
contributing my tax pounds to fund them for nothing, I value the
opportunity to be served at McDonalds by a Travel and Tourism graduate,
I thoroughly relish being asked if I want help with packing at my local
supermarket by a marketing graduate.

I'm proud to be able to say that my taxes enabled a generation of
f***ing wasters to be able to work for just over minimum wage in call
centres, supermarkets and fast food outlets and I am grateful for the
current government's education plans for generations to come, where else
would we find the fodder to staff our supermarkets and serve our skilled
Polish immigrant craftsmen?

Besides, if nobody went to university, who would get jobs to support
everyone else on state benefits?
--
Clint Sharp

Re: PCB UV Box - Follow Up
<SNIP>
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:-)



Re: PCB UV Box - Follow Up

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I dont wish to throw a spanner in the works but your tax pounds have very
little to do with UK universities these days. The vast majority of
undergraduate student funding is done by a)charging foreign students extra
(at least 11K per year, more depending on the course) to cover the loss
left over from only b)charging the home students 3K a year. Most university
equipment is funded through industrially linked research (and industrial
donations), which has to be fully economically costed, meaning all projects
have to be run as a business would including all costs inc office space,
technician time etc counted and charged to the project account - so they
cannot be considered to have an unfair advantage over industry. Research
council grants form a percentage of the money given to universities, but
only generally cover postgraduate projects which have to be fully justified
and peer reviewed before acceptance. And even they are sponsored  by
industry. If a group does not pull in funding for a year or two it is
effectively canned.

Uni's arent the public tax black hole they used to be, which is WHY they
have been forced (against their will, trust me) to create "micky mouse"
degrees which pull in people who will pay to do a course which takes little
supervision and still generates the same cash per head. To have purely
"useful" degrees for the small minority who can acheive them through skill
and interest, as opposed to just taking it as a way to muck about for 3
years, is not financially viable - that target market is too small and could
not collectively afford the actual cost of their tuition. If you want them
to drop their "micky mouse" degrees then you WILL pay for it in taxes!



Re: PCB UV Box - Follow Up
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Hmm, sense of humour bypass detected, donning flameproof attire. I would
say though, that if a penny of my taxes went to funding 'surf science'
or Travel and tourism courses, then I'd consider it wasted (WTF is a
travel and tourism course anyway?), I would much rather see the little
that universities do get of my tax pound going to fund 'proper' courses
instead of the bull*h*t 'we've got more graduates than you' games the
government has been playing for years now.
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  I have great fun taking the p*ss out of 'students' on Travel and
Tourism courses, hell, my niece is one (nice girl, recently got a full
page spread exposing her as a binge drinker in her Uni town evening rag)
and dumb as a post, but, bless, she'll have  a degree at the end of it
all if she can manage to keep her head out of the toilet long enough to
show up for a lecture or two so she should be ideally qualified to ask
if I want fries with that when I next visit McD's in her home town. You
imply I would deprive myself of that amusement.
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--
Clint Sharp

Re: PCB UV Box - Follow Up
Clint Sharp proclaimed to alt.electronics ...


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Totally agree, and yes a slight humour bypass - I tend to get defensive when
people attack the institutions I work for and have spent the last 8 years
doing 80 hour weeks to progress in, its only natural. And yes, we too skit
the mickey mouse degrees. Just be wary of tarring all "students" with the
same brush thats all :)

J



Re: PCB UV Box - Follow Up

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university
projects
justified
little
could

We, the people, gave the uni's 7 Billion this year, seems more than a 'very
little'. They also garnered an additional 6 Billion by the means you
mention.
As a taxpayer, I -expect and want- to pay taxes for higher education. I want
this country to be a centre of excellence and am happy to contribute to this
end.
I am very unhappy  to have to pay for the education of media studies
graduates,  golf course designers and the other dalliances.
The mickey mouse degrees are actually a true reflection of our present
social culture and are here to stay. Few youngsters want the  work entailed
studying subjects that would benefit the country in an industrial sense and
as the media studies people et al invariably come from well off, middle
class backgrounds and can pay their own way, then  it's time the uni's were
forgotten and my taxes spent in more worthy areas. (Honest!).
1% of the population now own 50% of the country's wealth. 50% of the
population own 1%, hence the country is  becoming little more than a large
offshore banking operation. Vastly wealthy bankers supported by a huge army
of servant workers. Industry? Technology?, forget it.
The Swiss are remembered for their Cuckoo clocks, we'll be remembered for
our bad plumbing.




--

Re: PCB UV Box - Follow Up
john jardine proclaimed to alt.electronics ...


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Not sure where you get your figures from, or if you see how they are split
down and attributed to what - as i say, most funding doesnt go to the
undergrad students.



Re: PCB UV Box - Follow Up
Here is a photo of my home-made UV exposure unit:

http://www.leonheller.com/PCB/UV%20box.jpg

It cost me about A3%25 to build it.

Leon


Re: PCB UV Box - Follow Up
Leon proclaimed to alt.electronics ...


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What do you use to sensitize the board? Or do you buy presensitized?

--
J
__________________________________________
http://www.jbuckle.homeip.net << My personal site
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Re: PCB UV Box - Follow Up

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Hi Leon,

Noted.  In the end I bought the one on eBay.  But still have an idea about
an LED UV box for the small size.

Aly :-)





Re: PCB UV Box - Follow Up

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it's
There's nothing special about these light box things. Don't allow
distraction by talk of weird and wonderful exotic materials.
The nail hardener thing (also insect killers, currency detectors et al)
wouldn't be worth the effort to break down and the UV tubes will be be quite
weak. It's quite painful to look at the bare blue light of a real UV box.
Built a box 7 tears ago for small 'one off PCBs'. Works well. Vital key is
those UV tubes which Maplin offers at 16 for 2.
Mine uses 4 Maplin UV tubes just clipped into 2 of those cheap 12V dc,
camping florry lights thingies. Stuck in a MDF box lined with cooking foil,
with a normal glass window and a 12V power supply.
High density black lines, printed on matt film and 7 minutes exposure gives
lines as fine as I can deal with. (ie those thin buggers that end up going
in between the 0.1" IC pads).








--

Re: PCB UV Box - Follow Up
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<SNIP>
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quite
foil,
gives

Hey John :-)

Perked up again this end.  Must be something to do with Clint and his taxes.
:-)

Back on track..  Reading..  Those Maplin tubes I believe to be 8W 12" T5 UV
tubes.  Two for 15 odd, Maplin YA39N.  About the same at Rapid, 34-0707.

These are what I'm looking at on eBay which I believe to be the same at
4.50ea.;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item32%0101581708

Out local shop for local people is charging...  5.84ea. although I'm not
sure if they'll allow local pickup.  I much prefer picking up locally.

http://www.bltdirect.com/products.php?cat10%37

I'm swaying towards thick perspex maybe, although have found that picture
framers are the ones to talk to about non-UV glass and offcuts.  4mm is a
minimum.

One of my electronic friends has mentioned banding caused by the intense UV
light in the area closest to the tubes, and is suggesting the 200 UV box
from Rapid, 34-0705 ;

http://www.rapidonline.com/searchresults.aspx?style=0&kw34%-0705

I just want to build one really.  Spending 200 goes against why I even do
any of this.  I do it for fun :-)

The bits I can source at no cost; IDC, switch, ballast, starters.  The
outlay will be the flight case, say 20.  The tubes, say 20.  Glass, say 5
odd.  So give or take 50 for a decent little box.

:-)

Aly



Re: PCB UV Box - Follow Up

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[...]

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taxes.
UV
UV
5
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Tell your electronics friend to go bollocks. Banding or shadowing occurs
when a tube fails. I.e when the dark end of a big PCB is seeing maybe 1/5 of
the UV at the bright end. And isn't it amazing how people always know they
will be safe from risk and critism by recommending expensive commercial
product as an 'answer' to  any technical question?

My ISP for some reason will not let me use Google, so will check the links
tomorrow.
They look useful as I'm after half a dozen UV tubes for a metal
photo-etching light box I'm thinking about. A fiver or so each seems
reasonable, after all they're just standard tubes with a modified coating.
Perspex, 4mm glass, both OK. Maybe even better is  the  double glazing
acrylic sheet  sold by Wickes B+Q etc. The stuff is designed not to
discolour from the UV in sunlight. The plastics have to be cut though and
it's maybe easier just to call into the local glass shop and have them cut a
piece to size for a couple of quid.

But yes. I love to see a good heartfelt rant!. Nowadays, seemingly becoming
a British cultural pastime.



--

Re: PCB UV Box - Follow Up

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ISTR reading somewhere that perspex is less UV-transparent than glass. Probably
more important is
that it scratches much more easily than glass. I think I used 3mm glass on my A3
sized box - easily
strong enough if supported all round.  

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Not a major issue - put some tracing paper or white paper on the glass and
adjust the glass-to-tube
distance so the illumination looks reasonably even to the eye. It's not too
critical.
 

Re: PCB UV Box - Follow Up
On Monday, in article
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......

Some plastics (e.g. Polycabonate) will block parts of UV bandwidth, don't
know any that block the whole UV bandwidth, if that was the case sunglasses
would be made of them.

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Scratching and easier to mark (etch fluids etc..) also more susceptible
to various bending and warping over time. The tubes do get warm. Also
some plastics have higher refractive index and lower transfer rate which
can mess things up. The lower transfer rate usually means the plastic heats
up a small amount as it absorbs some of the UV. Also means longer exposure
times to get same amount of cumulative UV to the object.

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Getting even illumination is a major key, over the whole area.
get your interlocks (microswitches and relays) as well as heat dissipation
if used frequently.

Remember looking at a project for UV curing a glue on a plastic sheet
6ft x 3ft, with 5 tubes a couple of feet away for optimum evenness and using
reflective UV tubes. These are specialist tubes with internal reflector layer
on 60% of the inside surface, tubes are used for tanning couches and
industrial applications. We got mock up done but full blown mechanical jig
never got built.

--
Paul Carpenter          | snipped-for-privacy@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/ PC Services
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Re: PCB UV Box - Follow Up
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Hi,
Hell yes, that looks fine. As long as you're happy to muck about with
the mains cabling then go ahead.  If you have doubts about suitability,
ask your local nail bar nicely if you can try theirs out! Bear in mind
the shipping charge though, you can probably buy a ballast, lamps and
fittings for less than the total and be guaranteed that you got the
right thing.

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Visit your local DIY shed, take a pen and paper, write down the
manufacturer name on the perspex/polycarbonate/polystyrene sheets, track
them down on t'internet and ask them... alternatively, ask your local
glass supplier for some offcuts and do some experimentation with
exposure (making sure not to get arrested in the process) Once you've
finished exposing yourself, go home and try the glass you just got, make
sure you mark the glass with the type first. Try a piece of photoresist
PCB with a sliver of each type of glass and an uncovered section all at
once so you can compare. Give it, say, 30 seconds and you should be able
to tell the difference.
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See my other reply.

Seriously though, you can make a nice UV box out of a cheap toolbox or
electric drill carry case if you have a mind to.. Alternatively you
could try eBay (yeah, 'cause you'll get a bargain there...) or even your
local freecycle, they seem to be full of academic/student types and may
know of an electronics department with a spare lying around that can be
acquired.
--
Clint Sharp

Re: PCB UV Box - Follow Up
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<SNIP>

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under

Hey again Clint,

Reading...  Glass/perspex noted.

Oh I definitely would prefer to build one, keeping in with the spirit.  A
small 320 x 260 x 90mm flight case is what I'm hoping for.

We'll see what happens.  :-)  The case comes first, as that's oddly the
hardest bit to source.  I'm not paying 50 for a case I can get for 5-10 if
I'm patient.  :-)

This will all be documented too when I'm done.  I'm allowing maybe 2-3 weeks
on/off to do this.  But still tempted by the 200 one at Rapid, I can afford
it but I'm just too tight.  :-)  Why spend 200+ when you can spend 50..

Aly



Re: PCB UV Box - Follow Up
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Also try local sign makers, neon signs especially, they will have
offcuts of all shapes and sizes. Consider adding a matching number of
white light tubes as well, that way you can use the light box to check
your artwork before you expose a board and find the transparency was
full of holes (bitter experience)
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Nice to find someone who isn't scared of doing something for themselves.
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How 'bout just under 20?
http://www.cpc.co.uk and search on order code TLTC03X
You could probably beat the price if you shopped around but if I were
building one, I'd consider using a scavenged flatbed scanner for the
case. You'd need to take some care stopping UV leaking out though.

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Totally agree, if I can't scrounge it or get it cheap I feel guilty,
patience pays off as it's only a hobby (at home) so I can afford to wait
if I can save a few pounds. Seriously though, if you can afford the 200
quid one, take a look at eBay, they do turn up every now and then and
generally sell much closer to your 50 quid than the 200 Rapid want.
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--
Clint Sharp

Re: PCB UV Box - Follow Up
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What's your opinion on this?  (and anyone's opinon for that matter).  I'm
humming and harring over it.  Trouble is the weight.  I can barely carry
25Kg.  Have a logic analyser which I don't use as it's too heavy to move
about, bought another one Thurlby LA4800 which is about 2Kg.  Anyway...

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item32%0100920597

250.  Double sided.  I'm tempted, but need pushing.  I fancied a little UV
flight case I'd done myself for 50.

What do you experts think on that eBay one?  They're just down the road too
so can pickup, have already spoken to the guy.

Alison :-)



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