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FW: Farewell and coolant-related machine shop question



I asked one of the folks in our region who is doing a lot of machine shop work about your question.  Her response is below.

Alice also suggested looking at the "ASM Materials Engineering Dictionary" edited by J.R. David, Davis & Associates, 1992, and information from "Condensed Chemical Dictionary," Lewis, 1997, for specific information on brass.

cmd

----------
From:  Chapman, Alice[SMTP:Alice.Chapman@METROKC.GOV]
Sent:  Wednesday, February 17, 1999 12:17 PM
To:  Catherine Dickerson
Subject:  RE: Farewell and coolant-related machine shop question

Hi,

I would say that yes the brass is the source of lead.  We did not test
"Valcool VNT 800"   but we did test Valcool Aerotech and Valcool Turntech (.
The pH ranged from 9.0 to 9.5 (this pH was measured in fluid taken from the
machining nozzle.)  We didn't measure pH in rinse tanks downstream of
machining.  The shop using Aerotech has an in-house recycling system where
they use a pH adjuster supplied by Cincinnati Milacron.  They did report
paint peeling on some of their machines.  The other shop is having no
problems at all and getting long fluid life too (3 years old).  

I would encourage the person to take look at the whole system, instead of
only focusing on the metalworking fluid.  It may be that the shop is putting
additives in the system that are causing the problem, or even the people who
maintain the machine.  One shop learned that their preventive maintenance
shop was using nasty chemicals to clean off gunk -- which ended up in the
sump and part of the machining fluid.

> ----------
> From: 	Catherine Dickerson[SMTP:cdickerson@pprc.org]
> Sent: 	Wednesday, February 17, 1999 9:54 AM
> To: 	Chapman, Alice
> Subject: 	FW: Farewell and coolant-related machine shop question
> 
> Alice,
> 
> I thought you may be able to shed some light on this question.  It comes
> from one the list serves I'm subscribed to.
> 
> Hope all is going well.  
> 
> Kate
> 
> ----------
> From:  Vincent R. Perelli[SMTP:v_perelli@des.state.nh.us]
> Sent:  Wednesday, February 17, 1999 9:12 AM
> To:  p2tech@great-lakes.net
> Subject:  Farewell and coolant-related machine shop question
> 
> Finally --- the question  -- 
> 
> A machine company is sawing brass parts.  Following the cutting
> operation, the parts pass through two rinse tanks.  The first rinse is
> picking up lead and exceeding the 5 ppm limit for hazardous waste
> determination.  Since the rinse is tap water (I told him to check pH), the
> culprit appears to be the cutting fluid ("Valcool VNT 800" from Cincinnati
> Milicron).  They can't change the brass formulation but could change the
> coolant.  The owner says the longer the parts sit in the rinse water, the
> higher the lead level.  Has anyone heard of a similar problem?  Does
> anyone know of a good, non-aggressive coolant?  Are there other
> possible sources of the lead?
> 
> Thanks everyone.   Keep up the great work that you all do.  I'm going to
> make sure that I maintain the P2 ethic in my new position.  Please keep in
> touch and I'll find opportunities for the same.
> 
> Sincerely,
> 
> Vincent Perelli
> NH Department of Environmental Services
> Pollution Prevention Program
> 6 Hazen Drive
> Concord, NH 03301
> 603 271-2902
> 603 271-2456
> v_perelli@des.state.nh.us
>