If you are speaking of temporary solder maskant to prevent solder from
going into certain areas during reflow or wave soldering, you are
speaking of peelable maskant from someone like Chemask. It is available
from other sources as well. 
But I don't know about a "lead-free" maskant, as no lead is in it. I
assume then that you are speaking of this type of maskant that can
withstand higher temperatures of lead-free processing. I do not know
what the upper temperature limits are of peelable maskants, but you can
inquire directly to them at:
http://www.advancetech-info.com/psm.html  
http://www.solderingsupply.com/index.htm
http://www.techspray.com/newinfo/2211.pdf#search='peelable%20mask'
http://www.qualitek.com/new3/mfgaid.html

For a UV curable mask, try Dymax at
http://www.matweb.com/search/SpecificMaterialPrint.asp?bassnum=PDYYMAX39
. I would expect that type of maskant to hold up to higher temperatures
than the ammonia-based materials.

There are many others. Be careful of using the ones that are not
de-ammoniated, as the ones with ammonia WILL attack your surface finish
on the PWB, especially immersion silver and immersion tin boards.

And finally, when you are trying to figure out why your boards are
failing cleanliness testing after adding this process, read this:

http://www.residues.com/pdf/CaseS12.PDF#search='peelable%20mask'

Just so you know that anything added has its own price to pay. You will
need to QUALIFY THE PROCESS to ensure you are not doing something
harmful to the product.

The health of the product must always be held in higher priority than
the cost of the process.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Leigh-Ann Litavis
Sent: Wednesday, February 15, 2006 1:53 PM
To: [log in to unmask]
Subject: [TN] Lead Free peelable solder mask

Hello Technetner's,

I was looking to see anyone has heard of a lead free peelable solder
mask?
Need to help a customer out.

Thank you,
LeighAnn Litavis

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to [log in to unmask]: SET
Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the
posts: send e-mail to [log in to unmask]: SET Technet Digest Search the
archives of previous posts at: http://listserv.ipc.org/archives Please
visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for
additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------