conformal coating

[RHRRC]

I need a conformal coating that will protect a pcb in a saline
atmosphere, maybe even the odd small drop of saline will land on the
pcb.
The temperature is room temp and the pcb dissipates only the odd mW
(no hot components)

Potting is not an option but dipping is!! (odd I know but
nevertheless)

Has ayone knowledge/experience of a suitable conformal coating?

Thanks

 

[MooseFET]

I need a conformal coating that will protect a pcb in a saline
atmosphere,

How long do you need it to work for. A coating just slows the
progress of the salt and water working its way towards the PCB.
Potting is thicker so it works longer.

maybe even the odd small drop of saline will land on the
pcb.

Put it in a sealed housing and drop the coating?

The temperature is room temp and the pcb dissipates only the odd mW
(no hot components)

Does it travel to the destination by air? Does it get exposed to sun
light.

Potting is not an option but dipping is!!  (odd I know but
nevertheless)

Has ayone knowledge/experience of a suitable conformal coating?

I have lots and lots of experience of unsuitable ones. I gave up long
ago and went the sealed housing route.

 

[FunkyPunk FieldEffectTrollsistor]

I need a conformal coating that will protect a pcb in a saline
atmosphere, maybe even the odd small drop of saline will land on the
pcb.
The temperature is room temp and the pcb dissipates only the odd mW
(no hot components)

Potting is not an option but dipping is!! (odd I know but
nevertheless)

Has ayone knowledge/experience of a suitable conformal coating?

Thanks

Dolph's

http://www.dolphs.com/pdfs/DOL_spraychart.pdf

The AC-41 is the stuff you want.

These are aerosols. They also have it in 1 Gal pails or bigger as well.

 

[FunkyPunk FieldEffectTrollsistor]

How long do you need it to work for. A coating just slows the
progress of the salt and water working its way towards the PCB.
Potting is thicker so it works longer.

Name one modern electronic conformal coating that is attacked by normal
saline solution.

What a total bullshit declaration.

 

[FunkyPunk FieldEffectTrollsistor]

I have lots and lots of experience of unsuitable ones.

Jeez what a stupid remark.

He is looking for someone with favorable experience, not some dopey ****
that gave up along the way.

 

[Nico Coesel]

Name one modern electronic conformal coating that is attacked by normal
saline solution.

The problem is not the coating, but there are always wires going
towards a PCB. This is where most of the water creeps in. Even regular
chips have this problem. Thats why chips need to be baked if they
where stored in open air for more than a few hours. Otherwise the
packages will split open due to boiling water.

 

[FunkyPunk FieldEffectTrollsistor]

The problem is not the coating, but there are always wires going
towards a PCB. This is where most of the water creeps in. Even regular
chips have this problem. Thats why chips need to be baked if they
where stored in open air for more than a few hours. Otherwise the
packages will split open due to boiling water.

Apples and oranges. Water contained in parts has nothing to do with a
sealed assembly being attacked externally by moisture.

Of course the proper sealing method would be to bake the assembly and
or apply vacuum to the assembly to remove ALL water from it BEFORE
applying the coating.

 

[[email protected]]

I need a conformal coating that will protect a pcb>
Has ayone knowledge/experience of a suitable conformal coating?

Thanks

I have experience with 3. Here they are, in order of effectiveness,
most effective first:
Parylene (Excellent)
.. Excellent performance, but requires expensive equipment to
apply.
.. Can not be dipped or brushed.
.. There are companies that will coat boards using Parylene.
Resiweld
.. Can be dipped or brushed.
Humiseal
.. The worst of the bunch, but OK for repair of small areas.
Regards,
Jon

 

[FunkyPunk FieldEffectTrollsistor]

Humiseal
. The worst of the bunch, but OK for repair of small areas.
Regards,
Jon

'Worst of the bunch'? YOU are the worst of the bunch.

 

[MooseFET]

  Name one modern electronic conformal coating that is attacked by normal
saline solution.

  What a total bullshit declaration.

Name one that doesn't eventually let the saline through.

 

[MooseFET]

 Jeez what a stupid remark.

 He is looking for someone with favorable experience, not some dopey ****
that gave up along the way.

This looks like another nym for Always Wrong. He seems to be
supporting the idea that a coating will work.

 

[MooseFET]

  Dolph's

http://www.dolphs.com/pdfs/DOL_spraychart.pdf

  The AC-41 is the stuff you want.

 These are aerosols.  They also have it in 1 Gal pails or bigger as well.

I am fairly certain that the AC-46 from these guys is one of the ones
I tried. It worked about the same as the others. ie: it failed to
keep the salt out of the PCB.

 

[MooseFET]

I have experience with 3.  Here they are, in order of effectiveness,
most effective first:
Parylene (Excellent)
.     Excellent performance, but requires expensive equipment to
apply.

We had it done by an outside company. It was about the best of the
ones I tried.

.     Can not be dipped or brushed.
.     There are companies that will coat boards using Parylene.
Resiweld
.      Can be dipped or brushed.

I have used one that can be brushed. Brushing without making bubbles
is a bit tricky. It is better to put multiple coats than to try to do
it all in one go.

Humiseal
.     The worst of the bunch, but OK for repair of small areas.
Regards,

Where I work, we called Humiseal "circuit stop". It was worse than an
unsprayed PCB.

 

[FunkyPunk FieldEffectTrollsistor]

Name one that doesn't eventually let the saline through.

Can you really be *that* stupid?

 

[FunkyPunk FieldEffectTrollsistor]

This looks like another nym for Always Wrong. He seems to be
supporting the idea that a coating will work.

You're a goddamned idiot. OF COURSE it would work!

 

[FunkyPunk FieldEffectTrollsistor]

I am fairly certain that the AC-46 from these guys is one of the ones
I tried. It worked about the same as the others. ie: it failed to
keep the salt out of the PCB.

You are devoid of facts, ie therefore full of shit.

What you know about coatings would fit on the tip of a molecular probe.

 

[FunkyPunk FieldEffectTrollsistor]

I have used one that can be brushed. Brushing without making bubbles
is a bit tricky. It is better to put multiple coats than to try to do
it all in one go.

Ever heard of reduced pressure, or a fucking vacuum, you retarded, know
nothing ****?

 

[MooseFET]

 Ever heard of reduced pressure, or a fucking vacuum, you retarded, know
nothing ****?

Yup it must be Dim Bulb AKA Always Wrong.

 

[FunkyPunk FieldEffectTrollsistor]

Yup it must be Dim Bulb AKA Always Wrong.

Yeah. I'm the guy that knows more about coatings and potting media than
a punk, pussy twit like you ever will.

 

[Nico Coesel]

Apples and oranges. Water contained in parts has nothing to do with a
sealed assembly being attacked externally by moisture.

A part is also a sealed assembly! So if a small sealed assembly can't
keep the water out, a big one can't either. Ofcourse you can use
better materials which slow down the ingress of moisture but
eventually you'll have moisture inside.

Of course the proper sealing method would be to bake the assembly and
or apply vacuum to the assembly to remove ALL water from it BEFORE
applying the coating.

That is standard procedure. Still, relying on the sealing is relying
on false hope. Water molecules are fairly small so they can creep into
very tiny openings.