Mercury vs Becquerel
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CasedImage.com wrote:I get much more shooting into a fine day.
Ha! I call those "Daguerreodays".
Well the thing with setting up a online community to promote discussion is that I guess I have to front up to questions. At the risk of horrifying practioners, here are some pics of my portable fume hood, at least it should generate discussion…
I am living in Ireland for 6 months and so had to build something temporary. The structure is made of lightweight pvc plastic pipe that holds top and bottom plates of black acrylic. The top plate has machine cut 100mm hole in the center for a pvc plumbing fitting of that size. Hanging down from the top plate is a thick polythene enclosure with the bottom plate inside it, giving a sealed space (apart from the front opening) with a flat sturdy floor. The whole thing sits in a window of a larger polythene tent/darkroom that hangs from a ceiling in the workshop space I am using. The pipes that make up the structure can be dismantled and so the whole thing can collapse flat, in theory.
It is big enough to have a fuming box or the mercury pot in it at one time with working space around the items. After development I don’t move the mercury pot till it has cooled right down even though it is a airtight condensing pot. I also wear rubber gloves for handling items inside the fume hood.
The fan unit is mounted in a window frame so there is only negative air pressure in the room and is connected by pvc ducting. It uses inert plastics, is airtight and when going has an airflow of 150 per min at the base when wide open and closer to 400 when the window is stoppered down a bit.
www.CasedImage.com
Hi Jon
I bought a inline fan designed for use with hydroponic cultivation. The ones you can buy for shower fans for bathrooms aren’t strong enough. Of course it all depends on the size of you fume hood/volume it has to work with. I got mine from the UK but there are lots of makes and models in the States. It doesn’t look very big in the photo but it is – have attached the stats with it. It was cheap – 20 pounds sterling.
There are probably better ones to be had so shop around. I need to dampen down this ones power as I use a alcohol lamp to heat my mercury pot and the flame gets pulled around a bit with the strong airflow.I have just realised that it has an aluminium casing… i may not keep it for the long term as Mercury and Aluminium don’t go well together – btw, bear this in mind when constructing a mercury pot! Mercury can disolve Aluminium, its why they don’t like it on planes.
Some stats on my In Line Duct Fan Hydroponics Extractor Fan –
100 Dia. spigots to suit standard ducting.
Up to 240 m3/h airflow rate.
73 Watts power consumption at full speed.
Will handle up to 350 Pa resistance, ideal for long duct runs.
Corrosion proof powder coated aluminium casing.
Long life ball bearing motor.
Thermally protected motor to prevent burn-out.
100% Speed controllable.
Sound level of 49 dB(A) @ 3m distance!!
www.CasedImage.com
Thought I you would show my set-up. The pot is made for half plates and sixth plates. I keep the mercury, bromine, and iodine inside the fume hood at all times (not shown in picture
). When I first began using bromine, the chemical company that sold it to me sent it in a regular glass bottle with a plastic cap! It should have been sealed with a special lead stopper! Anyway, their were burn bubbles forming on the plastic. I accidently cracked the glass which made it worse. The contents had to be poured into another plastic capped bottle, which started forming bubbles. That night I bought a PTFE 100ml bottle from a company in England (overnighter). It works very well! While I was pouring the bromine into the new bottle I accidently spilled some on my fingers (what a "daguerreotype recruit" thing to do). Let’s just say it burned like a muther @#!%&^$%! I stuck my whole hand in a big bowl of cold sodium thiosulphate for a good 5 minutes. Eliminated most of the pain and turned my burns bluish-grey. I took myself to emergency. "Everything will be alright" said the five foot two eyes of blue nurse, no amputations, no skin graphs, plus, the fine looking young lady (college medical student not much older than me) that was attending was also interested in old photographic practices! We talked for quite awhile. Anyway, that was about four months ago. Now that summer is over back to school I go (college). Another year of "no free time all study." I count myself very lucky if I’m able to make a few dags or pop off a few rounds at the shooting range once in a while. At least I get the whole month of December off! Daguerreotypemania here I come!!The classy daggist,
-Race G.
” title=”Wink” />Thanks for the pic Race, sounds like quite a chemical adventure you had. You definitely had double luck – what with no lasting injuries and an attractive nurse and med student to boot. You are most certainly lucky I wasn’t your nurse – no one has ever considered me pretty and I probably would have debrided your burns – ouch!
Looks like your setup is another vote for a commercially made fume hood (or you are a really skilled fabricator). Is that a recirculating filter on top or just the fan and duct shroud? I am working on plans for a homemade hood this weekend and I am trying to decide all the various aspects – fan size, cabinet materials, cabinet size, and also whether to filter my exhaust air. It is so great when people post pictures.
” title=”Very Happy” /> I was also wondering where you got your mecury apparatus. It too looks commercial grade. Is that a lid on top? Does the mercury stay inside or do you store it elsewhere? How often do you pull out the plate to look when you are developing? Do beginners ask too many questions?
Anyway, thanks for the informative post.
With Mercury Pot design, what are peoples thoughts on sealed versus open mercury pots? Because as individuals we operate under the radar of Health & Safety and Environmental regulatory bodies the onus is on us to develop standards that protect both ourselves and the environment. As a modern practice Daguerreotypy needs to be a respected name by such governance’s as the last thing we all need is to be perceived as environmental rogues that need to be legislated against.
A double darkslide arrangement (see attached image) provides airlock access to a lethal atmosphere. Contained within the mercury pot the danger will pass through the cooling down and condensing of the vapors, post plate development. A small amount of airspace around the plate itself is exchanged with the fumehood environment but this is a tiny fraction of what mercury vapors must escape from a heated open pot when the developed plate is removed. While judicious use of a good fume hood may protect you those vapors are still being released into the environment. Fans failing, backdrafts or power outages also present an unmanageable situation with a non sealed mercury pot.
The facility for measuring the temperature of the heated mercury is also important, over heated mercury means more being released into the atmosphere and will play havoc with your development also. thinking of mercury pot design I might also add to avoid Aluminium since mercury can dissolve it.
Reading various blogs, I get the feeling that there are many people heading towards mercurial development at the moment, some with the best features in mind (see attached image), so perhaps its an opportune time to remind everyone of our duty not only to ourselves but to the environment.
www.CasedImage.com
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