Doug,
I did forget to mention to blow the water off the board with an air gun, a
very important step.
Tap water limits are about 500mg per L, at least that is my quick check on
the web. Sounds like a lot compared to what I see here but lets use that
number.
Lets assume I have a 1mm drop (1/2 sphere) per square inch of PCB, that is
about 1/2 mm cubed. (Drops are very small after the air gun.
1 L = 10**6 mm cubed.
So, on my board I can expect .250g/10**6 = .25ug / in squared. Wow, sounds
low, did I miss a few magnitudes of 10 somewhere?
So how bad is tap water again?
I saw some specs allowing 10ug/in**2 so I guess that means I can have 40
drops of tap water per in **2.
Thanks
Bob Kondner
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
Sent: Tuesday, September 07, 2010 9:14 AM
To: [log in to unmask]
Subject: Re: [TN] Hand Soldering
Ohhhh, I beg to differ. Water soluble fluxes are more active and will
probably do OK for soldering, but they also represent a danger if you do
not totally remove them or if some of it flows into places and does not
get rinsed out. What really makes me nervous about your approach is your
choice of equipment and cleaners. Tap water sucks as a cleaner and hot tap
water only slightly better. You might be able to remove the visible
residues, but will still have invisible residues that will cause problems.
In some cases, you are putting on more contaminants with the tap water
than you are removing.
We use low residue fluxes here on class three product and have a number of
cases where the the residues are left in place. It is simply a matter of
finding a flux and cleaning combination that works well together, and
limiting the amount of additional flux you add. A skilled operator can do
soldering with no more flux than is in the core of the wire. You may need
a slightly larger core.
Ken, I would suggest this short list to you. Use either Kester 245 low
residue flux (P3 core) or Alpha Telecore Plus (also P3 core). Both are
standards here and work well for soldering. For topical cleaning
solutions, try Kyzen's Cybersolv 141b or Chemtronics Flux-Off Heavy Duty.
Both these cleaning agents work well with the fluxes I named.
Doug Pauls
Rockwell Collins
Robert Kondner <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
09/06/2010 01:27 PM
Please respond to
[log in to unmask]
To
[log in to unmask]
cc
Subject
Re: [TN] Hand Soldering
Ken,
In my mind there is absolutely no question, hand assemble using Water
Soluble flux. A good spray under hot water cleans well.
During final assembly or rework I might use a no clean at spots. The only
problem is the no clean is VERY DIFFICULT to remove so don't try. It
detracts from board appearance.
It the spot being reworked is a sensitive analog circuit they rework
using
Water Soluble. For anything close to fine pitch SMT you should be applying
liberal quantities of Water Soluble flux, only way to rework.
You can get a little "Water Pick" real cheap. Load it with hot water and
you can you can really get down into the nooks and crannies.
Bob Kondner
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kenneth Wood
Sent: Monday, September 06, 2010 8:30 AM
To: [log in to unmask]
Subject: [TN] Hand Soldering
Hi all.
What is the best setup for hand soldering as far as solder / cleaner?
Rosin core? Water soluble? No-Clean?
What cleaner too?
I've been using rosin core with various cleaners but I have a hard time
with
the white residue the cleaners leave.
Thanks
Ken
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------
|
