Covering bare PCB tracks

[David HK]

I have some new PCB two sided boards made in the USA. There is no silk screen nor any track covering.

After populating the board I plan to paint the tracks with ladies clear nail varnish to protect them against anything but mostly atmosphere damage.

Any views or comments?

I also have electrical varnish which is brown in colour and unsightly.


David in Hong Kong

[Bruce S]

Hello David;
I have used the liquid "hard as Nails" type stuff in the past for quick touch ups on PCBs, however once the unit is tested and known to be back in full working order I go back and follow up with a varnish or if outside a conformal coating as they are more formally called.
The Nial stuff seems to get too easy to chip off after a short while, I've gotten hooked on the stuff Rich Hagen used on the LED lights in the Philippines, a bit pricy, but for me its worth the extra pennies, plus as a spray on it covers stuff so much easier.

Hope this helps
Bruce

[madlabs]

Dave,

It depends on the enviroment that your board will have to survive. Here is some good info on conformal coatings:

http://www.humiseal.com/product-selector/conformal-coating

Jonathan

[ghurd]

I have used ladies fingernail polish for many years with perfect results.
Items I made 10 years ago are still working fine in dairy barns (very very humid, very hot or very cold).

In the US, we can get standard spray paint can sizes of various conformal coatings.
Krylon(?), and/or Sherwin-Williams industrial coatings division is the most commonly available to me.
G-

[rossw]

In the US, we can get standard spray paint can sizes of various conformal coatings.
Krylon(?), and/or Sherwin-Williams industrial coatings division is the most commonly available to me.

I can't support the use of Krylon ("crystal clear" IIRC) enough. This stuff is absolutely brilliant. Enormous dielectric strength, resistance in the gigohms-per-mm or something. Even smells great!

Assemble the board. Clean the board properly. Test it all works. Then go somewhere well ventilated, spray the whole thing - both sides. Do 4 medium sprays - one from each direction. The stuff goes sort of milky - you want all the spraying from different directions done while it's "milky" so it bonds together properly. (Different directions helps it get down both sides of componends, over solder joints etc)

When you've finished - if you've done it properly - you end up with a board that'll actually work underwater once it's dried. (I know, I've done it)

[ghurd]

There was some restructuring or something.  I can not keep it all straight.
Krylon was formerly a sub-division of Sherwin-Williams Industrail Coating Division?
Then... I dunno...
Same stuff has new names?
New companie's stuff has the old name?
Numbers stayed the same?
Something like that...

The stuff I have here is older Rome, but younger than TomW.   
Grainger carried/carries it on the shelf (3 miles from here).

Krylon, #1405, Clear Acrylic. "Varnish",  "V1".
11.5oz / 326 g spray can.
Dielectric strength 1523 VPM.
No Methylene Chloride.

Also still on my shelf:
Red V2 #1385
Green V3 #1386

I never had any problem at all with any of them.
G-