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October 2012

TechNet@IPC.ORG

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From:
"Goodyear, Patrick" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Goodyear, Patrick
Date:
Wed, 10 Oct 2012 21:45:01 +0000
Content-Type:
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Ethyl Alcohol - 200 proof, food grade anhydrous

Safer, cleaner, quicker, wide use range, water absorber, organic, no residues, does not attack plastics, easily disposed of, low flash point (fast drying).
Disadvantage, need to use in a WELL ventilated room, hooded vent also works, sniffing absorbs faster than drinking.   

I have used this substance for over 35 years, Uncle Sam's Yacht and Canoe Club specified it in the early 70's, we had to get it out of the Captains safe, we weren't allowed to use Freon based flux cleaners in a boat, also doubles as torpedo fuel.   

I have tried using the denatured 200 but it doesn't work as well and leaves a chalky residue behind, have to water clean after, same for 190 (shellac thinner) I assume that to be from the Methanol or other substances used in  denaturing.   

IPA    Isopropyl alcohol, Isopropanol, is not as reactive as ethanol as it has one less bond available (extra carbon atom) for cleaning,  it can have adverse reactions in the presence of some organics.    
In high concentrations it can also be a severe health risk.    We use this for degreasing and cleaning piping surfaces etc.  but not with electronics.     

I have seen this turn the cases on plastic dip packages white, which is really embarrassing when you are cleaning a multi-thousand dollar board and have to explain why all of the dips now need replacement as they have been, ah, damaged somehow.      

pat   


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey (EHCOE)
Sent: Wednesday, October 10, 2012 12:14 PM
To: [log in to unmask]
Subject: Re: [TN] Conformal coating removal

You can't get proper illumination of the substrate without Moon shine.
From one of the totally hilarious fellows (THF) Dewey

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, October 10, 2012 12:04 PM
To: [log in to unmask]
Subject: Re: [TN] Conformal coating removal

Hi, Pat
Why grain alcohol and not just IPA?

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Goodyear, Patrick
Sent: Wednesday, October 10, 2012 1:52 PM
To: [log in to unmask]
Subject: Re: [TN] Conformal coating removal

GDAIS Security Warning:
This message was delivered from the Internet. Be cautious about trusting the content, particularly any links or attachments.

If there is any doubt as to the authenticity, forward this email as an attachment to [log in to unmask] for analysis prior to opening any attachment or link.

Thanks, Yep it does have a very distinct odor and you don't want to spend hours sniffing glue.     But it is fast and effective, and with small areas it is the ideal method.    We clean with grain alcohol following.    We use a fume hood to draw off the vapors and process via a charcoal filter.

Pat

From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Wednesday, October 10, 2012 11:07 AM
To: TechNet E-Mail Forum; Goodyear, Patrick
Subject: Re: [TN] Conformal coating removal

Pat and Ioan,
I would be vewy vewy cautious with these.  Yes, they work, but the if it is the one I am thinking of (purple pen body), the chemical is tetrahydrofuran.  The smell of that chemical will knock a buzzard off a manure spreader at 50 paces.  The greater concern is that if you have any residual THF, hitting it with a soldering iron releases some REALLY nasty chemicals.  If you look back in the technet archives, Brian Ellis did a great dissertation of the bad effects of THF pyrolysis products.

On the other hand, you can take those same pens, pull out the fuzzy end, pour out the THF and refill with toluene to do what is needed.  But I still found that once that tip gets a little use, it creates the same fibers Ioan gets from the Q-tips.

Doug Pauls



From:        "Goodyear, Patrick" <[log in to unmask]<mailto:[log in to unmask]>>
To:        <[log in to unmask]<mailto:[log in to unmask]>>
Date:        10/10/2012 12:24 PM
Subject:        Re: [TN] Conformal coating removal
Sent by:        TechNet <[log in to unmask]<mailto:[log in to unmask]>>
________________________________



Ioan,

We use Conformal Coating Removal Pens made by Trace Technologies and distributed by Tech-Spray.    They are self-contained press tip pens that are about 4"x1/2" contain 12.5 ml fluid and have a wedge shaped felt tip, and we uses either Qtips or Foam tipped swabs to remove the duff.     Their website is Techspray.com the part number is 2510-N, the material is also in bulk.    You can maybe mix your own the chemicals are listed.    We purchased some in bulk but the pens are easy, exact, and disposable.

Pat
Pat Goodyear
Control Technician
Pacific Gas and Electric

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ioan Tempea
Sent: Wednesday, October 10, 2012 9:56 AM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: [TN] Conformal coating removal

Dear Technos,

We need to locally strip the acrylic coating (1B31S) from a few components, on a few thousands of boards. Right now we're using Q-tips to do the rubbing and, besides having to pluck tons of fibers afterwards, we're also going through a lot of Q-tips.

So the question is: is there anything else we can use, that will be more effective, cleaner and more economical?

Thank you,

Ioan Tempea
Ingénieur principal de fabrication / Senior Manufacturing Engineer [signature002]<http://www.digico.cc/>

950 RUE BERGAR, LAVAL, QC, H7L 5A1<http://g.co/maps/2gh3f>
T+ 1 (450) 967-7100, EXT244
------------------------------------------------------------------------
 [signature001] <http://www.facebook.com/pages/Digico/277076778479>
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Lauréat Dunamis 2012<http://digico.cc/dunamis-2012/>
Entreprise manufacturière / Gestion du capital humain


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