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Topic: Lead Fume generation potential from 'soft soldering'  (Read 7445 times)

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Offline lou

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Lead Fume generation potential from 'soft soldering'
« on: August 20, 2012, 08:34:16 AM »
I have read conflicting research regarding the potential for Lead fume generation during, what the industry terms, soft soldering (temps below 842F(450C)).  I understand lead has a vapor pressure of 1mmHg at ~973C, a melting point of ~621F (327C), and a boiling point of  3182F (1750C).  The solder used is ~60/40 tin/lead ratio.  If any of you could provide some objective evidence/data to either support or deny the claim that soldering at these temps will not generate lead fumes i would greatly appreciate it.  My background in Industrial Hygiene is limited however more so due to lack of equipment.  I am familiar with the potential health effects of lead inhalation/ingestion and the aliphatic aldehydes associated with the vapors from the colophony.  My question is aimed at just the potential for Lead fume generation.  Any responses are welcomed, thank you.

Offline Hunter2

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #1 on: August 21, 2012, 11:44:55 AM »
The tin lead alloy has an eutektikum. The solder temperature is 288° C or 550 ° F.

The fumes less but there existing.

https://www.google.de/search?q=soldering+lead+fume&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:de:official&client=firefox-beta

Offline lou

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #2 on: August 21, 2012, 04:34:28 PM »
thank you Hunter2.  I have already researched the page you provided and unfortunately the data is conflicting; the Lawrence Berkeley National study that states "it is unlikely that lead fumes will be generated during soldering" this is due to the very unvolatile nature of lead given its characteristics; while the other non-peer reviewed research denotes the commonly invalidated pontifications and recommendations.  Also even if fumes were generated, given the metals characteristics, the likelihood of any significant fume generation to rise to PBZ level seems remote or possibly implausible.  If you have any input regarding generation of lead fumes during this process and if so the quantification of such generation, please detail, thanks.

Offline Stepan

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #3 on: August 21, 2012, 08:25:23 PM »
Lead becomes airborne not in result of evaporation, but as mist, splattered away by boiling flux

Offline lou

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #4 on: August 23, 2012, 07:56:11 AM »
Thank you Stepan, the temp does not exceed melting point levels for the flux - soft soldering temps of no more than ~750F.  The materials are not heated to a level which would create any splatter.  That may exist during 'hard soldering' or brazing and welding. 

Offline Stepan

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #5 on: August 23, 2012, 07:38:18 PM »
I agree that chances to find airborne lead are close to zero.

Offline Stepan

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #6 on: August 24, 2012, 01:19:03 AM »
We test lead in air around soldering stations for years (I am owner of Industrial Hygiene Laboratory). Lead level is almost always below the detection limit of 2-4 microgram/m3. At the same time, if you collect surface contamination around the station, you will find enough lead. This indicates that lead does become airborne, it just doesn't stay in air long enough to be detected  ;D.

Offline lou

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #7 on: August 24, 2012, 07:23:59 AM »
Thanks for the great data Stepan. If clear in your mind could you recall the conditions of the monitoring event such as was it Area Sampling and/or PBZ sampling and was the duration of sampling a full 8hrs or averaged out due to short duration of actual soldering events - and how intense the soldering production was.  I am aware of the lead surface contamination potential and I know of the hygienic requirements with regard to lead particulates and ingestion issues (lead does not readily absorb in the skin so its more of an ingestion issue) so daily work practice controls are executed and enforced.  My objective is not to circumvent safety it is to see what evidence may exist to support the need for IH sampling, LEV, or other controls to address specifically lead fumes. Air sampling is always preferred given the multitude of variables however due diligence must be sought to obtain objective evidence before utilizing potentially superfluous costly sampling services.  thanks again Stepan.

Offline Stepan

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #8 on: August 25, 2012, 02:00:10 PM »
I replied on your personal email address  8)

Offline Enthalpy

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #9 on: September 05, 2012, 11:59:10 AM »
If you plan to export to the European Union, lead is banned from electronic products, including from soft soldering. The directive is called RoHS.
http://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive

As a consequence, we had to give up the good 60Sn-40Pb soft solder completely. Now everyone uses Sn-Cu-Ag or similar, which makes solder points that look uniformly bad (preventing to see if they succeed) and cost a lot. (At the same time, we replace incandescent light bulbs with power-saving models that contain volatile mercury, grzzzzwfffst!)
http://en.wikipedia.org/wiki/Solder#Lead-free_solder

So if your Company plans to export to Europe, the answer might be "use lead-free solder" rather than "does lead vaporize".

Offline vex

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Re: Lead Fume generation potential from 'soft soldering'
« Reply #10 on: September 19, 2012, 12:53:00 PM »
As a consequence, we had to give up the good 60Sn-40Pb soft solder completely. Now everyone uses Sn-Cu-Ag or similar, which makes solder points that look uniformly bad (preventing to see if they succeed) and cost a lot. (At the same time, we replace incandescent light bulbs with power-saving models that contain volatile mercury, grzzzzwfffst!)

Choose your poison! *chortle*  ::)

This made me laugh. What's more likely, here... will my child break a lamp at some point during his life, or will he eat his entire Game Boy?
University of Michigan Ph. D. Pre-Candidate, Inorganic Chemistry

Do or do not. There is no "try."

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