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colophony as pcb protection - long term?

colophony as pcb protection - long term?

2005-01-30 by Stefan Trethan

I have recently bought a can of "lötlack" made by kontakt chemie / crc
industries germany.
The text on the can tells me it is colophony, and the smell tells me it is
solved in alcohol.

I didn't know before buying, and hoped it would be less tacky than the
homebrew colophony solved in alcohol brush-on. Well, it isn't, but better
slightly tacky than corroded.

What i wonder, what is the long-term experience with this sort of resin
coating on a PCB? Can i leave it on with no worries?


Are there other products that are as solderable but less tacky?
I know i could leave the PCB uncoated until after soldering, and use a
plastic spray, but it seems incredibly practical to just spray the fresh
PCB and not worry about corrosion, and having the added benefit of a flux.

Spraying over the colophony with acrylic to stop the tackyness seems like
a bad idea. But i don't want to clean it off (that tends to be so messy
and wastes loads of alcohol).

ST

Re: [Homebrew_PCBs] colophony as pcb protection - long term?

2005-01-30 by Leon Heller

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, January 30, 2005 9:07 PM
Subject: [Homebrew_PCBs] colophony as pcb protection - long term?


>
>
> I have recently bought a can of "lötlack" made by kontakt chemie / crc
> industries germany.
> The text on the can tells me it is colophony, and the smell tells me it is
> solved in alcohol.
>
> I didn't know before buying, and hoped it would be less tacky than the
> homebrew colophony solved in alcohol brush-on. Well, it isn't, but better
> slightly tacky than corroded.
>
> What i wonder, what is the long-term experience with this sort of resin
> coating on a PCB? Can i leave it on with no worries?
>
>
> Are there other products that are as solderable but less tacky?
> I know i could leave the PCB uncoated until after soldering, and use a
> plastic spray, but it seems incredibly practical to just spray the fresh
> PCB and not worry about corrosion, and having the added benefit of a flux.
>
> Spraying over the colophony with acrylic to stop the tackyness seems like
> a bad idea. But i don't want to clean it off (that tends to be so messy
> and wastes loads of alcohol).

I've got something similar, made by the same people - SK10. It does tend to
be a bit sticky. I have a used a solder-through lacquer that works very
well, and isn't sticky, but I forget who made it.

I've found that my boards made using UV-sensitive resist-coated board don't
really need anything spraying on, they stay reasonably shiny for months.
There is probably a very thin film of resist left on the copper after
cleaning which protects it.

Leon



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Re: [Homebrew_PCBs] colophony as pcb protection - long term?

2005-01-30 by Stefan Trethan

On Sun, 30 Jan 2005 21:34:19 -0000, Leon Heller
<leon.heller@...> wrote:

>
> I've got something similar, made by the same people - SK10.

It's the same.

> It does tend to
> be a bit sticky. I have a used a solder-through lacquer that works very
> well, and isn't sticky, but I forget who made it.
> I've found that my boards made using UV-sensitive resist-coated board
> don't
> really need anything spraying on, they stay reasonably shiny for months.
> There is probably a very thin film of resist left on the copper after
> cleaning which protects it.

Might be. I observe rather quick oxidation with mine... (in a day you see
significant change)


ST

Re: [Homebrew_PCBs] colophony as pcb protection - long term?

2005-01-31 by Brian Clancy

G'day Stefan

It is years since I Used Lotlak but it was a very active flux. I don't
remember any corrosion problems.

These days I use Electrolube SMFL (surface mount flux) in a spray can. It is
not quite as active as I remember Lotlak to be, but, after a day or so it is
not sticky.

Cheers
Brian

-------Original Message-------

From: Homebrew_PCBs@yahoogroups.com
Date: 01/31/05 07:07:59
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] colophony as pcb protection - long term?


I have recently bought a can of "lötlack" made by kontakt chemie / crc
industries germany.
The text on the can tells me it is colophony, and the smell tells me it is
solved in alcohol.

I didn't know before buying, and hoped it would be less tacky than the
homebrew colophony solved in alcohol brush-on. Well, it isn't, but better
slightly tacky than corroded.

What i wonder, what is the long-term experience with this sort of resin
coating on a PCB? Can i leave it on with no worries?


Are there other products that are as solderable but less tacky?
I know i could leave the PCB uncoated until after soldering, and use a
plastic spray, but it seems incredibly practical to just spray the fresh
PCB and not worry about corrosion, and having the added benefit of a flux.

Spraying over the colophony with acrylic to stop the tackyness seems like
a bad idea. But i don't want to clean it off (that tends to be so messy
and wastes loads of alcohol).

ST


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