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April 2015

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Subject:
From:
Richard Kraszewski <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Richard Kraszewski <[log in to unmask]>
Date:
Fri, 24 Apr 2015 21:26:12 +0000
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Without a doubt,  MEoh will be even a poorer solvent than IPA to dissolve  silicone grease & mold release. Not than either are good enough to be useful for these. 

From a formulating standpoint MEoh will not dissolve most WOA anywhere  near as well as IPA or EToh.  Hence somewhat parallel in post flux residue cleaning. 

Rich  Kraszewski 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Tony Lentz
Sent: Friday, April 24, 2015 1:05 PM
To: [log in to unmask]
Subject: Re: [TN] methanol for cleaning

Hello JK,

I have no experience cleaning silicone grease or mold release.   Unfortunately I cannot give any advice on that.  

Best regards,

Tony Lentz

FCT Assembly
Field Application
[log in to unmask]
970-566-0360 Mobile

-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Friday, April 24, 2015 12:02 PM
To: TechNet E-Mail Forum; Tony Lentz
Subject: Re: [TN] methanol for cleaning

silicone grease?  dielectric? you don't mean small molecule mold release I assume.  not easy to clean (depends how clean you want to be.  if not done properly, you have a electrical contact near by, like zif contact, you might have problem later on... silicone migration).  wait until what your MFG is going say about that (or Brian E... ;-).
          jk
> Hello Phil,
>
> Most flux residues (liquid and solder paste) are soluble in alcohols.
> This includes methanol, ethanol, isopropanol, etc.   As flux residues are
> heated they become more difficult to clean.  Longer and higher 
> temperature reflow profiles make cleaning more difficult.  Some fluxes 
> also contain ingredients that are not truly soluble in alcohols, but 
> are able to be washed off by alcohols.  In this case, the alcohol will 
> lift off the residue, but it might redeposit on other areas of the circuit board.
>
> The evaporation rate of the alcohol is also a concern.  As the alcohol 
> molecular weight decreases (IPA > Ethanol > Methanol) the evaporation 
> rate increases.  Methanol evaporates faster than IPA.  As the alcohol 
> evaporates, the dissolved flux residues will redeposit on the circuit 
> board.  IPA is commonly used due to it’s relatively low evaporation 
> rate, ability to dissolve flux residues, and it's safety concerns.
>
> The trick is to wash the residues off fast enough to prevent 
> re-deposition, and to follow with a rinse of clean alcohol to ensure 
> that there are no residues left when the board dries.  This can be 
> done with liquid alcohol along with some type of wipes or Q-tips as Patrick stated.
>
> I know that Kyzen, Zestron, and others have done a lot of work to 
> formulate cleaners for just about every type of residue.  You might 
> want to ask your local cleaning chemical rep for some suggestions if 
> you are open to using a proprietary cleaner.
>
>
> Best regards,
>
> Tony Lentz
>
> FCT Assembly
> Field Application
> [log in to unmask]
> 970-566-0360 Mobile
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Nutting, Phil
> Sent: Friday, April 24, 2015 10:31 AM
> To: [log in to unmask]
> Subject: Re: [TN] methanol for cleaning
>
> Ok, so if I am spot washing flux off a circuit board or cleaning the 
> face of an epoxy insulator to remove silicone dielectric grease what 
> am I supposed to use?
>
> Brian,  I know you are very environmentally concerned.  IPA and the 
> like have been used for years by our industry and it is usually the 
> default cleaner for everything.  And yes I know alcohols do a better 
> job of spreading contaminates than removing them.  What then, if spot 
> cleaning, should be used?  (I know, "it depends".)  Manufacturing is 
> always complaining that Engineering creates designs and processes that 
> take too much time, but they work if done as designed.  Finding a 
> practical solution and changing the mindset is no small task.
>
> I look forward to your sage wisdom.
>
> Phil
>
> -----Original Message-----
> From: Brian Ellis [mailto:[log in to unmask]]
> Sent: Friday, April 24, 2015 12:18 PM
> To: TechNet E-Mail Forum; Nutting, Phil
> Subject: Re: [TN] methanol for cleaning
>
> Yes! absolutely! And it is highly toxic, to boot, with ingress to the 
> body by all means, including cutaneous. IMHO, avoid it!
>
> Brian
>
> On 24/04/2015 18:12, Nutting, Phil wrote:
>> We have had many posts regarding the ability of alcohol to evenly 
>> distribute flux and other contaminates over the surface of the board 
>> or part.  Does methanol do that same thing?
>>
>> Phil Nutting  |  HVP Development Engineer   |  Excelitas Technologies
>> Corp
>>
>> Lab: +1 978.224.4332   |  Office: +1 978.224.4152
>> 35 Congress St, Salem, MA  01970 USA
>> [log in to unmask]<mailto:[log in to unmask]>
>> www.excelitas.com<http://www.excelitas.com/>
>>
>>
>> [Excelitas R_emailsig]
>>
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