SuperGlue and WRT54G

[Drummerdude]

So, I'm a huge fan of DD-WRT and have made quite a few WRT boxes in my time, and I have a question. I have a current box that's configured as an outdoor bridge, and it sits in a pretty low " weather susceptible " area, but even then, it's still managed to get some moisture inside, and caused a bridge on the Broadcom chip, which I've fixed, and it's back up and running properly. My question, is can I use something suuuper cheap like superglue ( like the yellow superglue branded stuff you get at dollar stores ) to cover over the pins on the chips ( ram, bcom chip, etc ) and thusly, waterproof said chip?

 

[Harvey]

I don't know whether superglue is electrically conductive, but the solvents in it it may be, and they may also be corrosive to metal parts so, all told I don't think it's a good choice.

A better solution would be "corona dope," the paint (usually red) that you see around some components in electronic products. You may have seen it and tought it was fingernail polish. It's intended to be non-conductive and moisture resistant.

This Google search for "corona dope" should give you a start in learning about where to find it and its properties from several manufacturers.

One manufacturer's site, MG Chemicals, lists these qualities:

• Useful for high voltage applications
  
• Insulates components circuits and assemblies
  
• Excellent arc and corona resisting properties
  
• Protects motor windings and coils from arcing and discharge
  
• Protects against moisture and oxidation

 

[Compman55]

Cheap tube of regular clear silicone. Usually thr stuff in the big tubes at the hardware store.

 

[razel]

+1 above. That's the 1st thing I thought of. Some of the very rubbery ones are also removable... which reminds me... would rubber cement work as well? How about spraying layers of plastidip?

 

[Drummerdude]

So just a bit of clear silicone and I'm back into " relatively " weatherproof then?

 

[razel]

Actually... I would throw a silica packet in there 1st. That could be enough. At least it's not a near permanent solution.

 

[mfenn]

I doubt the OP much cares if an old WRT54G that's placed outside is permanently modified. The silica packet is a really good idea though, just tape it to the inside of the housing so that it's not covering any chips.

 

[Jeff7]

Conformal coatings are often used on electronics that have to go in a harsh environment, assuming they're not outright potted.

- You could do the silicone thing that was suggested, basically covering the board with it, avoiding connectors and switches.
- Conformal coatings are acrylic, silicone, urethane, or one of a few others. In lieu of a true conformal coating, I'm thinking to use this or this on the circuitboard: Mask off connectors, sockets, and switches, and then spray right over both sides of it.
Getting the coating into switches or connectors could cause problems, as capillary action may draw the coating in between the contacts.


I'm not sure which would be the better choice.
- The "Crystal Clear Acrylic" lists "moisture resistant" as a feature. The Fusion doesn't, though I would expect that it will be just as proficient in that area.
- The Fusion will probably adhere better. One tricky thing about the green soldermask is that it has low surface energy - things doesn't adhere to it very well, since the adhesive (or paint, in this case) can't properly "wet" the surface.
- I recommend multiple coats. 3 should do the trick.


If "spray paint your electronics" sounds a bit odd, check out the "How do you apply Conformal Coating?" section here.
Note that one of the methods is "dipping."
Some other circuitboards get stuck in a container, and a 2-part epoxy is simply poured over top of the assembly, completely entombing it.

 

[Drummerdude]

Thank you everybody for your replies. I'll be researching all of your suggestions, and deciding on one. I really appreciate the guys here at Anandtech. Been reading forum posts and worklogs for YEARS. You guys are a huge mess of information that's helped me learn quite a bit over time.