Denatured will leave behind a residue, we use punctilious 200 proof Ethyl (not ethanol) no residue whatsoever and will evaporate in seconds. The spray de-fluxers draw moisture when they condense on the boards, the 200 proof absorbs moisture. Our environment is at 70-80% humidity so it helps to keep the boards dry.
I learned this trick in uncle sam's yacht and canoe club 30+ years ago, it was the only alcohol allowed on submarines, the doc kept it under lock and key.
Pat
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Karen Tellefsen
Sent: Monday, October 31, 2011 9:26 AM
To: [log in to unmask]
Subject: Re: [TN] Rookie question on RMA fluxes
Food grade is 190 proof (95%) as it has to be distilled with water. 99% ethanol must be distilled with another, less savory solvent, like benzene.
Why is food grade better than than denatured ethanol as a cleaner? Some of the denaturants are fairly harmless, like IPA.
Karen Tellefsen - Electrical Testing
[log in to unmask]
908-791-3069
Re: [TN] Rookie question on RMA fluxes
Goodyear, Patrick
to:
TechNet
10/31/2011 10:44 AM
Sent by:
TechNet <[log in to unmask]>
Please respond to TechNet E-Mail Forum, "Goodyear, Patrick"
I use alcohol on a regular basis to clean fluxes, but it is NOT IPA, I use only pure Ethyl "grain" alcohol undenatured 200 proof (this stuff is food
grade) It can be a little expensive and you have to pay the state and
federal taxes on it, but as a cleaner it is fantastic. There a very few
problems with it, it will craze some polycarbonates but one just has to be
careful. The other drawback is you have to use it in a VERY WELL
VENTILATED room as you will not be able to drive after you use it in an enclosed area for a prolonged period, you may not even be able to walk.
pat
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ioan Tempea
Sent: Friday, October 28, 2011 9:42 AM
To: [log in to unmask]
Subject: Re: [TN] Rookie question on RMA fluxes
Technos,
Once again, thanks for the inputs. The funny part is, it seems that RMAs are still in demand in my corner of the planet, which is, guess what, the home of the Montreal protocol.
BTW, the alcohol cleaning of the RMA is something that was humming around my brain, as I was sure having heard somewhere that this is the solvent for RMA residues. Good thing I've asked.
While you folks were considering my question, I've looked up RMA in Wassink and B. N. Ellis and MacLeod Ross' books, with not much success in finding specific cleaning methods, so it became kinda clear for me that this type of flux is not different from the rest, cleaning wise.
Anyways, I shalt get ready for the challenge.
Best regards,
Ioan Tempea, ing.
Ingénieur Principal de Fabrication / Senior Manufacturing Engineer T | 450.967.7100 ext.244 E | [log in to unmask] <mailto:[log in to unmask]> W | www.digico.cc <http://www.digico.cc/>
N'imprimer que si nécessaire - Print only if you must
De : [log in to unmask] [mailto:[log in to unmask]]
Envoyé : October-28-11 12:28 PM
À : TechNet E-Mail Forum; Ioan Tempea
Objet : Re: [TN] Rookie question on RMA fluxes
Ioan,
You have gotten a lot of good answers to the question so far and I will chip in my two cents worth.
Technically, there is no such thing as an RMA flux anymore, though the term continues in use. RMA, Rosin Mildly Activated, was a flux terminology from the good old days of MIL-F-14256, the military flux specification. It was cancelled in 1995 and directed people to J-STD-004, the current predominant flux specification in the industry. The older rosin flux formulations that were termed RMAs, translated into ROL0, ROL1, or ROM0, depending on the flux and who you ask. RMA fluxes are still available, though as the market shrinks for these, they are becoming more expensive, which encourages users to transition to something more modern.
Most people still using "RMA" flux are using the 15% solids, which is still pretty high, compared to low residue fluxes or water soluble fluxes. Which means there is a significant amount of flux to clean off compared to other fluxes.
Isopropyl alcohol sucks as a cleaner, at least in my opinion. People want to use it because it is cheap, available almost everywhere, does not impact industrial emissions much depending on where you are in the world, and is not a health hazard, if you don't get too wrapped around the axle over flammability. No way, no how would I ever want to clean an RMA flux with alcohol alone. Does not work reliably.
In my experience, high solids rosin fluxes tend to be OK if you leave them alone, or if you totally remove them. If you "kind of" remove them, you have a great deal of problems. You remove the encapsulating effect of the rosin (which you want), but you free up the activators to cause havoc (which you don't want). In my view, you want a really effective heated saponifier in an in-line aqueous cleaner, with a thorough heated deionized water rinse.
Doug Pauls
Ioan Tempea <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
10/28/2011 08:07 AM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
Ioan Tempea <[log in to unmask]>
To
<[log in to unmask]>
cc
Subject
[TN] Rookie question on RMA fluxes
Dear Technos,
Although I've been around in this trade of ours for quite a while now, I have never had the occasion to work with RMA fluxes. I need to know how this functions. How can RMA be cleaned, I've heard about alcohol...? Is regular aqueous wash enough? If alcohol only, do we need a special equipment? Anything else to know?
And, anyways, are RMA fluxes still available?
Also, I imagine most of you at ease with RMA have tried to talk your customers into converting to water soluble flux chemistries. How hard was that? Is it possible?
Thanks,
Ioan Tempea, ing.
Ingénieur Principal de Fabrication / Senior Manufacturing Engineer T | 450.967.7100 ext.244 E | [log in to unmask] <mailto:[log in to unmask]> W | www.digico.cc <http://www.digico.cc/>
N'imprimer que si nécessaire - Print only if you must
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