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James Carr-Pries

James Carr-Pries

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Type

Description

Advantages

Disadvantages

Price / Purchase links

Silicone Resin (SR)

Confromational Coating using a Silicon Resin Base

  • Higher working temperature (-40C to 200C) 

  • High chemical and general resistance protection

  • Challenging removal (need special solvents, long soaking periods and even brushes)

  • Expensive

$37CAD - https://uk.farnell.com/electrolube/fsc400/coating-silicone-flexible/dp/1616570 ($37)

Acrylic Resin (AR)

Confromational Coating using a Silicon Resin Base

  • Most Affordable

  • High Dielectric Strength 

  • Very easy to remove (using a variety of solvents)

    • Good for reworking and debugging

  • Simple drying process (<20 minutes)

  • Working temperature range: -40C to 60C (short term protection to 100C)

  • Not the best in class at protection but still sufficient

https://www.mouser.ca/ProductDetail/MG-Chemicals/844AR-340G?qs=T3oQrply3y9urZcHv3hIkA%3D%3D$16CAD -

$28 but free shipping to Canada https://ukwww.farnellamazon.com/electrolube/apl400h/coating-conformal-acrylic/dp/3026838?st=Conformal%20Coatingca/MG-Chemicals-Acrylic-Lacquer-Conformal/dp/B008OA7178/

Potting Materials

Potting uses a "pot" in the form of a case, shell or similar enclosure, to completely cover the board, protecting it from the surrounding environment - a tough form-fitted shell around the board.

  • potting cases are secure

  • offer dielectric protection

  • safeguard the PCB from the polluting effects of acids, bases, corrosion, salt and most solvents

  • Very challenging to remove for reworking/debugging

  • No ventilation

Due to these downsides of potting, it would not be feasible for our purposes.


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  • Other teams have resorted to just applying a silicon coating after all the debugging is done or using a full 3d printed enclosure. I would hesitate to take these routes because of my understanding of our project constraints. We are heavily dependant on passive air cooling so fully enclosing the board may not be feasible. Also, from what I understand we had the dust issues before the competition and need a solution during the testing phases too.

IPC Standards

Todo

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Does it actually work? - look for reviews, actual tests

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  • IPC-CC-830C: This is the main standard for conformal coating. It is used to qualify different conformal coating products, and contains sections on materials, shelf life, curing, chemical, viscosity, and appearance requirements. It also contains standards on fungus, moisture, and flammability resistance as well as dielectric withstanding voltage and other electrical specifications.

  • IPC-A-610G: This standard covers the acceptability of electronics assemblies, and as such has a section on the requirements for conformal coating coverage and thickness.

  • IPC J-STD-001F: This standard covers the requirements for soldered electrical and electronic assemblies, and has a section dealing with materials and application of conformal coatings

General Overview of PCB Protection Methods: https://www.tempoautomation.com/blog/what-are-the-best-pcb-moisture-protection-methods/

IPC Standards for Conformational Coatings: https://resources.pcb.cadence.com/blog/2020-understanding-ipc-conformal-coating-standards

Choosing the coatings best for us: https://www.techspray.com/the-essential-guide-to-conformal-coating

https://www.electroniccoating.com/resources/conformal-coating-comparison-guide/

General Information about various types of coatings: https://electrolube.com/knowledge_base/what-are-conformal-coatings/

https://www.techspray.com/conformal-coating

Tech Sheet for Acrylic Resin (first link): https://www.mouser.ca/datasheet/2/265/tds-844ar-a-1600563.pdf

Todo

  1. Continue Discussion with other Solar Car Teams on reddit