Genny, If you're hunting for info on the Net, the Hot Oil levelling process used also to be known as "Hydro-Squeegee". It did indeed produce a fairly flat finish ( often better than some HASL finishes I've seen), but as the name suggests, it's messier than an air knife. If dim and distant memory serves at all well, Hot Oil Reflow did just that - it reflowed the solder on the board with no attempt to level it in any way, whereas the Hot Oil Solder Levelling or Hyrosqueegee method did level solder. My previous Company used to use it recover boards from which the components had been salvaged, or on which the HASL finish was too thick to start with. This process originated in the days of "conventional" technology (plated through-hole), and I haven't so far heard of it being used for SMT boards. Not to say it couldn't be used for SMT, but HASL is possible more accurate and less contaminating. Peter Duncan Genny Gibbard <Genny.Gibbard@W To: [log in to unmask] AVECOM.CA> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Sent by: TechNet Aero/ST Group) <[log in to unmask] Subject: [TN] Hot Oil > 11/10/01 01:27 AM Please respond to "TechNet E-Mail Forum." You learn something new (or new to you) every day. I was just told of a board finishing process called Hot Oil Solder Levelling. It was portrayed as a very flat, nice finish. I was also told that it is old technology, which may be why I am not familiar with it. It is only within the last year that I have really gotten involved with specifying board finishes. I've been searching on the internet to learn more and am a bit confused. My questions: Is Hot Oil Reflow and Hot Oil Surface Levelling the same thing? If not, what is the difference? What are advantages/disadvantages to this over HASL, or any of the newer so-called 'flat' finishes needed for fine pitch? Thanks. Genny Gibbard (mailto:[log in to unmask]) --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------