MIL-I-46058 and IPC-CC-830 are both material qualification documents and
the discussion of pinholes and bubbles refer to the condition of the
coating on the qualification vehicle.  IPC-610 and J-STD-001 would be more
applicable to bubbles, etc., found on electronic assemblies.

Doug Pauls



                                                                           
             Joel Alexander                                                
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             04/25/2007 10:50          Re: [TN] bubbles in conformal       
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IPC-CC-830 is a standard used by the manufacturer of the conformal coating
to qualify their material. Can these also be applied to the application by
the end user. IPC-A-610 states that bubbles are acceptable as long as they
do not bridge adjacent conductors.

Also is there a specific reference that states anything about the
appearance of foam?



Joel Alexander
Quality Assurance Manager
TT APSCO, INC.




Edward Mines <[log in to unmask]>
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04/25/2007 10:26 AM

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[TN] bubbles in conformal coating






MIL-I-46058 & now IPC-CC-830 say conformal coatings should be "bubble
free". Some have interpreted this as meaning that a few small bubbles away
from components are acceptable.
  Foam is not acceptable.

  Some polyurethane conformal coatings generate gas as they cure. They
should not be coated on very humid days.

  Bubbles are also apt to form in conformal coatings when the coating is
too thick. I've seen this happen in between closely spaced tall components
even when the coating on most of the board is within customary limits and
has no bubbles. The solution was to change the application technique.

  Get the coating and equipment manufacturers involved. They want your
future business.

  Ed Mines


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Ahhh...imagining that irresistible "new car" smell?
 Check outnew cars at Yahoo! Autos.

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