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What type of brush for hand conformal coating?

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#60600

What type of brush for hand conformal coating? | 2 December, 2009

Hi all, just wondering what type of brushes you all are using to manually touch up/apply your conformal coatings? We use an solvent based acrylic and do minor touch ups as they are processed. Occasionally we will have a bristle or two come off the brush and get trapped into the coating. Of course since the brush is ESD Safe everything (including the bristles) are conductive and can not be left on the PCB. Just wondering if there is a higher quality brush we could be using to reduce this problem.

Thanks

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#60601

What type of brush for hand conformal coating? | 2 December, 2009

why brush? why not spray?

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#60604

What type of brush for hand conformal coating? | 3 December, 2009

We spray with an Asymtek C-740 system. However, some very small PCBs we do by hand and we also touch up after a PCB has to be repaired.

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Lou

#60605

What type of brush for hand conformal coating? | 3 December, 2009

The quality of the brush is most important. We use artist brushes from Torrington Brush Works. Sable works best but are the most expensive. We use more camel hair. They work best for us as we "hand coat" hundreds of boards a week and go through many brushes. Yes, a few hairs will fall out occasionaly but they obviously need to be removed while the coating is wet and uncured. That is why we conduct a QA coating inspection prior to the cure. You can also use disposible brushes that have stapled bristles vice being crimped in the brush.

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#60606

What type of brush for hand conformal coating? | 3 December, 2009

Thanks, no ESD concerns using a non conductive brush though?

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Lou

#60607

What type of brush for hand conformal coating? | 3 December, 2009

Once you dip it in liquid, the make-up of the brush does not really matter as it is now coated. A dry brush is a different story.

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