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conformal coating selection

terry sun


conformal coating selection | 23 November, 2000

Hello to all out there, We're considering CC process,and would like to know some defferences between SSC3 of Electrolube and Humiseal 1B73, yes,I know that SSC3 is silicone one,and Humiseal 1B73 is solvent based acrylic as well as other basic properties,but I'm not sure about their long term reliability.Is there a repairability issue for SSC3? I'm also told that all coating method except dipping will surely cause "Shadowing",do you have any experiences?How to avoid it? Do you have any data for shadowing?

Any information concerning comparison about these two materials is highly appreciated.

Thanks and Best regards! terry

Maunfacturing Engineering Lucent Technologies,Qingdao,China Tel: +86 532 8702000 Ext. 3034 Fax: +86 532 8701998 Email:

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Re: conformal coating selection | 24 November, 2000

Terry, I've never had to deal with conformal coating but I do know that automotive parts manufacturers do a great deal of CC. These are the people that I would be looking to for your answers. Particularly in regard to long term reliability, extreme conditions and repair issues. Darby.

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Re: conformal coating selection | 27 November, 2000

You'd more than likely have repairability issues with the Acrylic based one. The acrylic-based finish is alot harder and more brittle versus the silicone. Some of the new silicones, you can just "peel" with your fingernail, while still getting reliable adhesion....Dow's 4105 is a good example.

As far as "reliability"...what are you looking for? Reliability of the coating with respect to dielectric, or environmental protection?

Shadowing can be eliminated completely if you get a heat-cure type coating...after it's heatcured, the coating is cured even in "shadowed" areas.

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Re: conformal coating selection | 27 November, 2000

Contact: Graham Naisbitt

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Re: conformal coating selection - oops | 28 November, 2000 CONCOAT Ltd Alasan House, Albany Park CAMBERLEY GU15 2PL UK Tel: +44 (0) 1276 691100 Fax: +44 (0) 1276 691227

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Graham Naisbitt


Re: conformal coating selection | 28 November, 2000


The SCC3 product is a vinyl modified silicone. It is less able to perform at low temps as it becomes brittle. It is not easy to repair because it is essentially silicone. It is not a qualified material to the MIL-I-46058 Spec.

Are you sure you will have proper tech support where you are?

HumiSeal 1B73 is not a harder product. Its flexibility is as per any qualified coating i.e. it must pass a 3mm mandrel test.

1B73 is an acrylic therefore it can be stripped more easily. It is qualified at a temp range of -65degC to +125degC. If you need more then you could consider HumiSeal 1H2O a new water based coating that will go to 200degC.

If you want more please look at our web site:

Hope this helps - BTW thank-you DaveF - I am not paying enough attention to this site, sorry.

Regards Graham Naisbitt

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Graham Naisbitt


Re: conformal coating selection | 28 November, 2000


Sorry, I just re-read your question and failed to answer all your questions:

Shadowing only applies to coatings that are UV curable. Neither of these are UV curable. You do not want this technology for 3 dimensional assemblies, it is too expensive, difficult and other stuff.

Regarding reliability data - both of these materials have been around for over 25 years. We know of no reliability issues in respect to the coating - he assemblies yes, the coatings no!

Regards Graham

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Re: conformal coating selection | 5 December, 2000

Being in the automotive electronics industry, we use silicone (Dow 4105 is one in particular). I'll ask the same question - What are your reliability requirements?

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