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Topic: [DIY] (protective) mask for selfmade PCB (Read 636 times) previous topic - next topic

fabiopigi

hi

i'm doing all my etching at home with some chemicals :)
well, the traces are all fully exposed that way.

is there any way to protect them with a layer, like those red/blue/green layers on factory-made PCBs?
nothing complex, just covering some traces.

maybe some kind of nailpolisch would already be enough, but has anybody already tried?

trialex

When I do toner transfer home-etched boards, I just don't remove the toner after I have etched it! The black sits over the copper just like a soldermask.

It burns/boils away from the pads when you touch the soldering iron to it. It seems to have no effect on the electrical or mechanical properties of the joint.

fabiopigi

yeah, i do toner-transfer.
i guess its a good idea to leave the toner on the circuit :)

any other methods?

westfw

Are you just trying to make it look prettier?  After it's all done you can probably use any sort of spray clear-coat on the solder side, but I wouldn't do that before soldering on components.  There are some spray-on coatings that serve as flux (http://www.lpkfusa.com/Store/ProductDetail.asp?ProductID=107) plus LOTS of special-purpose "conformal coatings" designed to protect PCBs from all sorts of highly specified environmental "issues", but they tend to be very expensive.

There are also assorted products for tin-plating your PCB.

Frankly, if you're going to solder your board relatively soon after making it, I don't think any of these are worth the trouble.  While the copper traces will oxidize on the surface, the oxide is a bit like Aluminum oxide - it's protective of the remaining copper, and the PCB will stay in working condition for decades (while at least one of the tin plating products I was looking up contains exactly the sort of fluxes that you are NOT supposed to used on electronics...)  It'll just look not so pretty...

I don't think I've ever seen a home fabrication friendly soldermask material that actually works as a soldermask (ie holds up to soldering heat on nearby parts of the trace.)  THAT I'd like to find  (I think "real" soldermasks tend to be 'cured' epoxy-like things, nasty and difficult to deal with in home environments...)

macegr

I've considered using high-temperature spray paint and then etching off the solder pads with the laser cutter at Techshop. Haven't tried it yet, and it's not exactly a technique that could be used in any home PCB fab, but interesting anyway.
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