PCB Coating home made

[prashanth10gm]

hello all

Happy new year 2011!!!

I wanna know how to make the PCB coating ( green layer) after etching of the PCB .... So how i do it in home... please help me with this ... thanks in advance


regards.,
prashanth

 

[VSMVDD]

in the pcb factorys this is usualy a resist layer done by mask
usualy a fine wax is printed on the inverse of the resist

then painted by spraying and washed with hot water when dry ...
the wax lifts and you have your coating its also brushed to remove straggles

there are a few methods

you can just solder first then spray with coating at home...

simple .. no need for special stuff.. just a can of resist spray...

or just silver plate the pcb or gold plate

many home solutions are avalible
gold plate is nice and not too expensive

i would say gold is better

as some pcb disease or corode from flakes of crisps or acids from cooking etc
cause a break in the copper
paint is full of small holes cracks and fishers... so avoid it


gold is far better
silver goes black

so what i do is silver plate then dip the board in 'oxy' + peroxide + water 20/30/50

then it turns very black 'hyperoxidised'
then plate it again with either gold silver or platinum

VERY effective for vhf uhf shf and ushf

VERY... esp platinum ontop of gold

i use a cd4059 pulse dc programmable plater {i made it can pass circuit if needed}

you can use a high tension to give all tracks even if not connected to an electrode
to plate
just the board has the potential
just need an eht like TV coil 25kv and plate solution ...
same for thru plate using copper sulphate and some nickel salts {works well for glass fibre{

the eht is controlled by the 4059 chip via its driver}}

 

[prashanth10gm]

Can you give the detailed procedure please ....with what are the materials used and where will i get those materials

 

[FvM]

The ideas about galvanic plating are quite interesting, but I don't think, that VSMVDD is exactly answering the original question.

The "Green layer" on industry standard PCBs is a solder mask. It has been produced (and is still for high volume, low performance) by screen printing and is mostly structured by a photo process with today's PCB technlogies. It's required for machine soldering, to keep the solder at the terminal pads and avoid solder shorts.

The solder mask isn't designed primarly as protective coating, although it offers a basic enviromental protection. I don't see a DIY method to produce a solder mask, except a photo process.

Coating the assembled board, e.g. by Contact 71 polyurethane spray would be my suggestion, if envirometal protection is intended.

P.S.: An example of a prototype solder mask kit

 

[rajudp]

there are two types of solder mask mainly used first one using screen printing method and next is the UV solder mask

 

[VSMVDD]

we are talking 'at home' not pcb multi !!!

so solder and spray with paint or to intrinsic level use silicone covers{
silicone squidge gum {for mines or other gas hazords}

you will find resist GREEN BLUE etc
infact paint !!!
not pcb 'photo' resist exposing chemical
{note the use of photo maybe i left this out last post}

but paint!!! simple paint

i give exact process

solder and spray or make a silicone layer on it

go to motor factor after you solder it
choose a paint non metalic

use it

cheep and chearfull $ stuff

simple and clean

i know exactly what too do
use paint and not resist chemical ment for photo exposure

its obvious i didnt mean this by terms and my non lack of knowlage

---------- Post added at 17:14 ---------- Previous post was at 17:08 ----------

i use art fixer spray first then use a hard based latex paint

---------- Post added at 17:16 ---------- Previous post was at 17:14 ----------

its worth pointing out

in eda you have chemical resist and photo resist coatings

both come with a preamble noun

any chemcial resist or car paint is already chemical proof esp cars
they have to cope with just about anything
sometimes they are better than conformal pcb resist paint!!!!

---------- Post added at 17:26 ---------- Previous post was at 17:16 ----------

detailed procedure

make pcb etch solder on stuff

spray with art fixer
apply latex paint after testing leave ic pads clean of paint

if you want to electroplate boards
you need metal salts and more elaberate tanks and washes ,.

 

[KJ6EAD]

If you want to recreate the UV cured epoxy coating used commercially, you would spend more on materials than to just buy it already made. Here's one type: Chemtronics Launch Page. If you're just looking for a conformal coating, Chemtronics, Techspray and MG Chemicals all have something.

 

[pranam77]

A special Transparent coating solution is available for preventing Home made PCB's from oxidation. The solution is taken by a "cotton waste" swab held with a foreceps, and then smeared over the shiny copper of the PCB. The said solution cost about 100-120 Rupees per 100 Ml in Indian market. The solution when dry, is directly soderable without the need for scrapping.

 

[Jigar 4 Electronics]

A special Transparent coating solution is available for preventing Home made PCB's from oxidation. The solution is taken by a "cotton waste" swab held with a foreceps, and then smeared over the shiny copper of the PCB. The said solution cost about 100-120 Rupees per 100 Ml in Indian market. The solution when dry, is directly soderable without the need for scrapping.

Is there any other tricks available, today ???