Re: gEDA-user: Tin pest

[Marvin Dickens <marvindickens@xxxxxxxxxxxxx>]

Karel Kulhavy wrote:
> It looks like lead free solder may disintegrate after 1.5 year when
> exposed to cold weather. This may be serious issue with electronics
> stored or used outdoor in winter.
>
> http://materials.open.ac.uk/srg/srg_tp.htm
> http://www.indium.com/drlasky/files/TinPestPaper0723Final.pdf
> http://ap.pennnet.com/Articles/Article_Display.cfm?Section=Articles&Subsection=Display&ARTICLE_ID=216209
> http://www.smartgroup.org/pdf/tinpest.pdf
> http://www.semiconfareast.com/pbfree.htm
>
> Anyone has first-hand experience or can comment competently on the
> issue?
>
> What are actual health hazards of soldering with Sn-Pb solder? 
The health concerns of soldering go beyond the type of metals that 
compose the alloy the solder
is made out of.  Another major concern (Just as important) are the fumes 
from the flux that is used.
Over time, they _can_ be deadly.


>  Do you
> know about suitable homemade measure to prevent Pb contamination of the
> solderer's organism? Is there Pb in the soldering fumes
>   
I don't know about home made equipment, but we use fume hoods that have 
walls on three sides along
with a top. The font of the unit has a forth wall that slides up and 
down so you can get the work into the unit.
Once the work is in the unit, the user slides the wall down and puts on 
rubber gloves. There are two openings
in the sliding wall for the user to insert his/her hands and tools. The 
fume hood extracts air at a rate
of 30 feet per minute. Anything that gets loose in the hood is sucked 
into a HEPA filter stack which vents
out on the root (Yes, the HEPA filter stack makes the whole thing legal).

The part of the body that is most vulnerable to absorbing things 
(Including metals and organic materials)
are the eyes. The eyes are the most absorbent part of the human body 
that are exposed to air and are
a major point ot entry for hazardous materials in the work place. A 
second major entry point is the
mouth and noise.  A simple, low technology rule of thumb is if you can 
smell it, your getting exposed
and it's getting into your body.

There are only two ways to protect yourself against contaimination:

1.) Negative pressure devices such as fume hoods that remove the 
offending material(s).

2.) Positive pressure devices such as full head facemasks with air pumps 
that force air into a facemask that
covers you entire head (Including the eyes). This type of gear is common 
in industries where containing
the offending material is difficult or not practical.

Best

Marvin