PCB Protection

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Hi all,
I have mastered the art of producing PCBs using photo resist, UV exposure etc, but now find that some of my older boards are starting to corode!
How does one protect them from corosion? or is there some way I can tin all the copper tracks like the pro's do?

Any help will be apreciated

DieterD
 
Hi Dieter

There are several ways to solve this :
1. The use of a plastic/solder spray
2. Tin bath

The first is obvious i guess and can be bougth in every parts shop.

The second (i never tried it), you can buy (e.g. Conrad in germany, holland and probably farnell) tin plating stuff which you can apply without to much difficulty.
Mix a sachet of this tin plating stuff with ???, throw in your board for a while and.......................... done.

grtz

Simon
 
Tin bath

I have tried the chemical tin bath approuch too but gave it up after a couple of tries (I tried several brands of bath).
The bath is extremely liable to even the slightest contamination and most times it isn`t possible to keep it that clean.
The PCB itself has to be extremely clean too.
Even minimal residue of cleaning (water, solvent, finger prints or whatever) prevent the tin bath from working properly.
Also at some PCB`s where the bath seemed to function okay, after a while (some month) there was a blackening (corroding) of the surface again.
To do a tin protected PCB at home as the pro`s isn`t almost possible IMO.
I give my self made PCB`s to a professional PCB manufactorer now.
They coat them by a hot air tinning process. That works great is easy to solder, looks good and protect the PCB almost forever. Besides, it is also cheaper than the tin bath.
And: no mess with this toxic liquids at home.
 
What company is this ?
Hi Simon:

No, it is a small local company. We have even several of these here.
Depending on where You`re located, there might be one near You. Take a look at Your local "Yellow-Pages".
That`s the way I found the company where I have made tinning my PCB`s.
The small quantities of PCB`s I have once in a while, is not really big business for them (actually they always seem to be rather amused) and so sometimes they do not even charge me because the bill would be of more effort than what it`s worth the tinning (and so mostly the only thing I pay is a donation in their "coffee funds"):)
 
DieterD,

I've asked the same question in another thread before. From all the help and suggestions by fellow members I finished my PCB protected.

Jackini suggested "Liquid Tin" or "Tinnit" the product is called. It works wonders with my boards. In less than a minute they were tinned at room temperature and any surplus can return to the original container save for future use. No mess ;)
But I learned that better to finish all your drilling and soldering prior to protect it with Silicone Laquor a couple of layers. But you need to have a very sharp probe when taking measurements on the PCB to get a good contact.

Hope this helps.
Chris
 
I remember there's a kind of solder-painting, sold in little glass bottles. I don't know the right name of it, but I saw it in my local dealer shop. You must apply it with the included little pencil.

You can also try to resolder the tracks, but I'm afraid the tracks will go off when heating them too much.

Best regards,

HB.

EDIT: I see chris_ma is talking about the same product.
 
another solution for small PCB`s

Below You can see a tin brush for a Weller (Cooper Tools) soldering station.
It is mounted instead of the solder tip.
This works to some extend for smaller PCB`s but the tin does not get so evenly distributed and does not look as good as a professional tinned PCB.
 

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i used plastic spray with all of my boards
and it´s definitely enough protection (just stinks like hell and isn´t very healthy; do this outdoors if you can)
during my learning as repair technician i was told more than once never ever to resolder whole tracks which makes them prone to break.
in some series of grundig tv´s you quite often have interruptions at those resoldered tracks
 
Protective Coatings

When you start to do digital and the traces are 10 mil, it's time to seriously think about coatings -- Allied Electronics and others sell a couple conformal coatings to consider -- Konform SR Conformal Coating, Konform AR, Print Kote -- these have high dielectric strength -- spray on. For high voltage aps you can use Corona Dope.
 
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