Bit of a Random one this

rossnunn · Post by **rossnunn** » 09 Dec 2005, 20:38

Does anyone know of a substance thats easily applyable, waterproof but not conductive & is not likey to melt plastic / solder etc

andmcit · Post by **andmcit** » 09 Dec 2005, 20:45

What are you hatching up!?

Not sure about the conductivity side of things but isn't HEAVY grease something that's cheap and easily available in large quantities?

I'm thinking of the waterproof sludge type that sticks like watchamacallit on the blanket NOT the more commonly used LM or Graphite Grease...

Just a thought!

Andrew

AndersDK · Post by **AndersDK** » 09 Dec 2005, 21:07

For protecting & sealing electric & electronics circuits there is a wide selection of dedicated sprays available.
Look at Maplin's website.

rossnunn · Post by **rossnunn** » 09 Dec 2005, 22:49

nothing fancy, my cross-overs have suffered water ingress, I've cleaned them but want to seal them to stop it getting any worse

andmcit · Post by **andmcit** » 09 Dec 2005, 22:58

rossnunn wrote:nothing fancy, my cross-overs have suffered water ingress, I've cleaned them but want to seal them to stop it getting any worse

Bathroom/standard housework Silicone sealant in a tube that you'd use for sealing a loose headlight glass will do that no probs!!

Andrew

jeremy · Post by **jeremy** » 10 Dec 2005, 08:03

Maplins do loads of small boxes specifically for electronics - with appropriate glands, grommets etc. Also silicon greases. Another alternative is to set the boards in a bath of polyester resin and make into a transparent brick.

dnsey · Post by **dnsey** » 10 Dec 2005, 09:59

Bathroom/standard housework Silicone sealant in a tube that you'd use for sealing a loose headlight glass will do that no probs!!

Sorry to differ, but silicone sealant gives off acetic acid as it cures, which will eventually corrode the board and components.
What you need is a conformal coating - widely used and designed for just this application - protects against vibration too.

andmcit · Post by **andmcit** » 10 Dec 2005, 10:39

dnsey wrote:
silicone sealant gives off acetic acid as it cures, which will eventually corrode the board and components.
What you need is a conformal coating - widely used and designed for just this application - protects against vibration too.

Didn't realise this. Do you know whether acrylic sealant has a similar effect?

Andrew

Kowalski · Post by **Kowalski** » 11 Dec 2005, 22:03

If a silicone isn't appropriate because of the aceitic acid, there are alternatives. There are numerous latex based sealants (is silkaflex latex?), various modified silicones etc. One I've used is "Nail and Seal", I'm not sure exactly what it is, but it doesn't smell of aceitic acid. It's particularly good for sealing things because it will stick to a variety of materials that silicone won't, it even sticks to some plastics that are "difficult" to glue. It isnt expensive, stays rubbery when cured and it works as an effective glue (holding the soles onto a pair of my trainers!).

dnsey · Post by **dnsey** » 12 Dec 2005, 10:31

Why use a substitute for the correct material?
Try, for example, RS product no. 714-462
rswww.com

JohnT · Post by **JohnT** » 12 Dec 2005, 15:35

Some of those 'No nail' adhesives shrink as they dry out, the last thing you need on a delicate PCB. Go for a covering which is designed for the job. I agree that a trip to Maplins is on the cards.