Conformal Coating

[danrogers]

Hi All.

I work for a small company offering battery management solutions.

The majority of our products end up in cars and vehicles or different types so we offer conformal coating as a solution to vibration, moisture etc.

We are currently using Electrolube APL which seems ok. The issues we are having is how to keep the coating out of sockets. We have 'blank' sockets which we plug in the connectors but sometimes the coating still manages to find its' way inside the connectors.

Has anyone else had experience with machines or hand coating? Before or after soldering sockets on?

Any tips / advice would be very much appreciated.

 

[crutschow]

I know in some cases they use tape to block the conformal coating from where it's not wanted.

 

[ronv]

Might check with the printed circuit assembly house. We used to have some "goop" that could mask certain potions of a board duing the wave solder process. It would then peel right off (and out of) the holes.

 

[Sceadwian]

Something like a liquid latex might work, not sure of the size of these connectors though removal might be a little tricky.

 

[danrogers]

there are 6 connectors per board, they are 3 10 pin sockets, a 10 pin header, a 30 pin and a 34 pin. We tend to use Molex, Wuerth (for IDC) or Samtech.

When you say 'goop' do you mean it masks the points whilst coating aswell or just soldering?

I was wondering if there was something we could use to enable us to coat before soldering sockets on (we solder sockets by hand but the boards are flow soldered)?

Has anyone had any experience with coating machines?

Thanks all

 

[ronv]

We used it to mask holes for components that could not be wave soldered, but I think it might work for your conformal coating as well. It was kind of like a thick latex but would tolerate the heat.

 

[danrogers]

The problem is that we would rather coat after we fit sockets and we are not sure how to mask the sockets?

 

[danrogers]

no-one else experienced these issues?

 

[ronv]

This is the stuff we used to use. You may be able to put it on the sockets, conformal coat, then peel off along with the conformal coating. What do the sockets look like? Maybe I have the wrong idea.

Amazon.com: Chemtronics Solder Mask, Chemask, Lead-Free, 8 fl. oz.: Home Improvement: Reviews, Prices & more

 

[danrogers]

Hi there, the sockets are a mixture but we mainly use Wuerth IDC headers
**broken link removed**

 

[BeeBop]

Couldn't you just fill the sockets with plugs which you remove after applying the coating and before it completely dries? The plugs can then be re-used on the next board... etc.

 

[danrogers]

Hi BeeBop, thats what we currently do but the sockets quickly get messed up after a few use's, and sometimes we find that they let the coating in around the edges.

the ideal thing would be to have a cap of something that covers the whole socket but I have no idea how best to go about making some.

Any ideas how to get around these issues?

 

[ronv]

The picture was worth a thousand words. How about painters tape.

 

[danrogers]

Hi, that might not be a bad idea, is that known as masking tape?

 

[ronv]

Painters tape is masking tape that is easy to remove even after a couple of weeks. Seals well on the edges as well. Made here by 3M. Masking tape should work.