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#31
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![]() DieSea wrote: Someone hasn't filled is boots with lead and heaved him overboard I hope Sorry, but that's no longer possible. RoHS came into force on July 1st. They would have to have filled his boots with non-toxic lead substitute. As for heaving somebody overboard, please remember that Dihydrogen Monoxide restrictions will come into force as of September 1st. Please see http://www.dhmo.org/ for more details. |
#32
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![]() The Radio Amateur Formerly Known As G4KFK wrote: (snip) As for heaving somebody overboard, please remember that Dihydrogen Monoxide restrictions will come into force as of September 1st. Please see http://www.dhmo.org/ for more details. Good news for the soap-dodgers, then. 8-) |
#33
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![]() Steve wrote: (snip) Which makes it very frustrating that the net aimed at mobile phones and MP3 players turned into a sieve to encompass low volume long life items in fixed installations and even church organs.... that's much the normative behaviour of our interpretive legislators - take a simple EU directive, bloat it out of all proportion, then when there's a complaint, it can be pinned on those nasty EU beaurocrats. In the meantime they'll get knighthoods for being so diligent - much easier than polishing the handle on the big front door.. Ah, it's medication time. Nurse!!! |
#34
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In article , litle ole me
writes except that there is NO LEAD CONTENT IN THE FLUX FUMES. Lead does not vaporize until much higher temperature than soldering temperatures... There will be lead in the fumes; molecules regularly detach themselves and float off into the air from liquids (and can also do so for some solids under certain conditions) at well below the vaporization temperature, perhaps you have not noticed that water at room temperature will evaporate, remember: molten is a liquid. This is why mercury spills are such a problem, and why several years ago laboratories (schools etc.) had to incur expense having floors lifted and mercury removed by special vacuum cleaners, and using mercury vapour detectors to variety 'safe' levels. A few weeks ago I had to clean a spill caused by a broken thermometer from a cupboard. -- Ian G8ILZ |
#35
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Prometheus wrote:
In article , litle ole me writes except that there is NO LEAD CONTENT IN THE FLUX FUMES. Lead does not vaporize until much higher temperature than soldering temperatures... There will be lead in the fumes; molecules regularly detach themselves and float off into the air from liquids (and can also do so for some solids under certain conditions) at well below the vaporization temperature, perhaps you have not noticed that water at room temperature will evaporate, remember: molten is a liquid. This is why mercury spills are such a problem, and why several years ago laboratories (schools etc.) had to incur expense having floors lifted and mercury removed by special vacuum cleaners, and using mercury vapour detectors to variety 'safe' levels. A few weeks ago I had to clean a spill caused by a broken thermometer from a cupboard. so, what protection should we use when soldering? how much lead would have been ingested? Having worked in a production and engineering environment for many years, I would think that were there any risk of lead in solder fumes, there would be HUGE guidelines from the EPA. but, there are none. we had fans and filters to control the flux fumes, which were quite pungent.) in your logic above, chemicals that are far fro similar are being equated and their properties simplified. water and mercury are liquid at room temp. mercury, like lead does not evaporate at soldering temperatures. (for ref: vapor pressure of water at 100C is 760 MM, or 100X the below. try putting 37 C or even 200C in the math below, and I think the answer will be that the vap press is minute and unmeasurable.) _____ http://prola.aps.org/abstract/PR/v26/i6/p851_1 Vapor pressure of lead, 1118° to 1235°C was found to vary from 5.70 mm to 19.70 mm in good agreement with the equation log10p(mm)=-10372/T-log10T-11.35, which also fits the best results of Egerton at lower temperatures. The heat of vaporization of lead at its melting point is calculated to be 46,300 cal. The chemical constant comes out -1.40 which is close to the value -1.59 computed from the quantum theory of monatomic gases. ____ no one I know solders at 1118 degrees c or higher? water has a vapor pressure FAR lower than lead. please realize that the vapor pressure of lead and the vapor pressure of water are NOT close in value. by the above logic, my desk is evaporating. I know ice can evaporate. how do can the the number of formica molecules floating out of the kitchen counter be calculated or measured? here is a bit from wikipedia. Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. Most often the term is used to describe a liquid's tendency to evaporate. It is the tendency of molecules and atoms to escape from a liquid or a solid. At any given temperature, for a particular substance, there is a pressure at which the vapor of that substance is in equilibrium with its liquid or solid forms. This is the equilibrium vapor pressure or saturation vapor pressure of that substance at that temperature. The term vapor pressure is often understood to mean the saturation vapor pressure. A substance with a high vapor pressure at normal temperatures is often referred to as volatile. The higher the vapor pressure of a material at a given temperature, the lower the boiling point. the end. |
#36
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what about resin lung then ? .......
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#37
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There may not have been any EPA guidelines in the past ... but there are
now. I see them every day, all solder stations in our plant haves mandated exhaust facilities - even labs. Particulates are more of a concern rather than vapors. Roger "litle ole me" ""nobody \"@ nowhere.com" wrote in message .. . Prometheus wrote: In article , litle ole me writes except that there is NO LEAD CONTENT IN THE FLUX FUMES. Lead does not vaporize until much higher temperature than soldering temperatures... There will be lead in the fumes; molecules regularly detach themselves and float off into the air from liquids (and can also do so for some solids under certain conditions) at well below the vaporization temperature, perhaps you have not noticed that water at room temperature will evaporate, remember: molten is a liquid. This is why mercury spills are such a problem, and why several years ago laboratories (schools etc.) had to incur expense having floors lifted and mercury removed by special vacuum cleaners, and using mercury vapour detectors to variety 'safe' levels. A few weeks ago I had to clean a spill caused by a broken thermometer from a cupboard. so, what protection should we use when soldering? how much lead would have been ingested? Having worked in a production and engineering environment for many years, I would think that were there any risk of lead in solder fumes, there would be HUGE guidelines from the EPA. but, there are none. we had fans and filters to control the flux fumes, which were quite pungent.) in your logic above, chemicals that are far fro similar are being equated and their properties simplified. water and mercury are liquid at room temp. mercury, like lead does not evaporate at soldering temperatures. (for ref: vapor pressure of water at 100C is 760 MM, or 100X the below. try putting 37 C or even 200C in the math below, and I think the answer will be that the vap press is minute and unmeasurable.) _____ http://prola.aps.org/abstract/PR/v26/i6/p851_1 Vapor pressure of lead, 1118° to 1235°C was found to vary from 5.70 mm to 19.70 mm in good agreement with the equation log10p(mm)=-10372/T-log10T-11.35, which also fits the best results of Egerton at lower temperatures. The heat of vaporization of lead at its melting point is calculated to be 46,300 cal. The chemical constant comes out -1.40 which is close to the value -1.59 computed from the quantum theory of monatomic gases. ____ no one I know solders at 1118 degrees c or higher? water has a vapor pressure FAR lower than lead. please realize that the vapor pressure of lead and the vapor pressure of water are NOT close in value. by the above logic, my desk is evaporating. I know ice can evaporate. how do can the the number of formica molecules floating out of the kitchen counter be calculated or measured? here is a bit from wikipedia. Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. Most often the term is used to describe a liquid's tendency to evaporate. It is the tendency of molecules and atoms to escape from a liquid or a solid. At any given temperature, for a particular substance, there is a pressure at which the vapor of that substance is in equilibrium with its liquid or solid forms. This is the equilibrium vapor pressure or saturation vapor pressure of that substance at that temperature. The term vapor pressure is often understood to mean the saturation vapor pressure. A substance with a high vapor pressure at normal temperatures is often referred to as volatile. The higher the vapor pressure of a material at a given temperature, the lower the boiling point. the end. |
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