Lead fume generation potential during 'soft soldering' 1

[loucapa]

Hello,
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; or have any supportive data indicating levels not exceeding ~50micrograms/m3 of lead fumes in a standard soldering station setting wrt PBZ, 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 during soldering. To validate the potential of lead fume generation by scientific evidence in lieu of atmospheric sampling would be a more pragmatic approach if the science is founded. My objective is to see what evidence may exist to support the need for IH sampling, LEV, etc. Air sampling is always preferred given the multitude of variables however due diligence must be sought before utilizing potentially superfluous costly sampling services. Thank you for your responses.

 

[MiketheEngineer]

Use non-lead solder - commonly available.

 

[loucapa]

Thank you for the response. I understand the alternative solders available however mil-spec standards and current governing production requirements dictate the use of non - lead free solder.

 

[MiketheEngineer]

So what's the problem - no lead - no lead fumes??

 

[loucapa]

'current governing production requirements dictate the use of non- lead free solder' IOW No the alternative lead-free solder cannot be used. Do you have any input regarding generation of lead fumes during this process and if so the quantification of such generation? thanks.

 

[tomwalz]

Might try your solder supplier.
Might try Lucas Milhaupt.

Everything we have ever done has been to control the fumes.

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[loucapa]

thanks tom, the manufacturer/supplier does not provide general information regarding product exposure assessments - they will only recommend LEV equipment or point source control measures. I understand the hazards associated with such a toxic substance and am very familiar with all types of hazard controls, however i am hoping someone with the requisite knowledge in chemical/material engineering can clear the air with regards to the potential of such a non-volatile heavy metal to actually create significant fumes within atmospheric breathing zone of an operator or in the surrounding area. Maybe its a long shot but i figured this forum may produce some desired responses. Unless my inquiries go unanswered, I am not willing (nor would anyone) to submit to a local IH group btwn $1k to $2k to inform me that the only concern is the colophony (rosin) vapors. For those questioning the humanistic element of this query, LEV is already in place however with the exception of Lead 1910.1025 either IH monitoring or objective evidence needs to be provided. I am looking for that objective evidence, regardless of whether the local exhaust is capturing all fumes and no overexposure exists. I appreciate all responses, thank you.

 

[mcgyvr]

Lead will NOT be present in typical electronic soldering processes smoke/fumes. However lead will be ALL over the work surfaces,etc.. But it does not vaporize at soldering temperatures and will not be present in the fumes. The fume extractors are for flux/rosin smoke removal. We had an IH in here with monitoring necklaces for all our employees.. Not a single one showed any lead in the smoke/fumes/air. However work surfaces were covered with it daily and hence should be cleaned daily/tested with those LEAD swabs,etc... Employees should always wash hands before eating/drinking/smoking,etc..

 

[loucapa]

Thank you mcgyvr! 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) yes daily work practice controls are executed and enforced. Could you possibly elaborate on the reasons why no fumes were generated or were you not privy to that information? Or could you give me a more detailed acct of your soldering production effort was it short/long durations of soldering and was it frequent/infrequent? If not, you have provided me with some worthy statistics indicating that there is proof Lead Fume generation during soldering may not need controls depending on the intensity of the work effort. thanks again

 

[mcgyvr]

The testing was performed for 1 full shift (8 hours). I have the chemical analysis somewhere but remember that lead was not present in any significant amount.

Frankly I have found virtually NO information on the chemical content of solder fumes other than flux components in it. Other sites mention lead oxide fumes but I believe that is related more to other "higher temp operations" like welding/brazing,etc.. processes and not typical electronic soldering. Many sources say there is lead in the fumes but no information backs that up.

The electronic soldering industry simply uses fume extractors with a carbon filter media and that's IT.. No further protection is ever mandated. I'd hope its not all a giant coverup by the electronics industry and that we are all dying from lead fumes.. Heck we have "fume extractors" that are no more than a box fan with a carbon sponge filter in front of it..and never are the fumes evacuated out of the building for hand soldering.

We are planning on a redesign of our floor layout and I intend to actually vent all soldering fumes outside just because it makes me sleep better at night knowing that I'm not just blowing whatever it is right back all over the building/work surfaces.
We also have a selective soldering machine and it does put off quite a bit of flux fumes and lead particles do go airborn and make their way 8-10 feet from the solder pot.. We use a hepa vacuum system for cleaning and all rags,etc... are sealed up in a plastic bag before being disposed of.

In general, (until the world wide solder fume cover up is exposed) ha ha.. Simple fume extraction/sufficient cleaning methods and routine hand washing,etc.. are the norm and should be enforced.

 

[loucapa]

Mcgyvr, thanks again for your historical data i really appreciate it. I welcome from any other member, additional objective evidence to support the claim of no occupationally significant amounts of lead fumes generated during soldering.