Probably a silly question, but after the etched PCB is completed, soldered up, tested and declared a finished project, does anyone treat the copper to prevent oxidizing?
I've thought of spraying it with clear coat, but I have no idea what's the right thing to do...
Quote from: pgodfrin on September 12, 2020, 03:59:34 PM
Probably a silly question, but after the etched PCB is completed, soldered up, tested and declared a finished project, does anyone treat the copper to prevent oxidizing?
I've thought of spraying it with clear coat, but I have no idea what's the right thing to do...
I mist it with a waterborne lacquer soon after i remove the etch mask before i even solder. The heat of the iron vaporizes the lacquer when you touch the iron to the pad, no problem to solder with it covering the copper. Even if you don't get to populating and soldering the pcb for months down the road, easy as can be, no oxidization.
dave
Nope. I've got dozens(no, literally) of etched and strip board pedals with no post treatment. Work just fine.
Sent from my iPhone using Tapatalk
OK. What's "waterborne" lacquer?
There's dedicated flux/protector that you can spray on after etching, before soldering. Especially handy if you want to store the boards for a while before soldering. When you've already soldered them, I don't think there's a pressing need to do anything (perhaps cleaning the flux, but I always use no-clean solder).
Quote from: pgodfrin on September 13, 2020, 07:47:39 AM
OK. What's "waterborne" lacquer?
Waterborne just means the solvent used to make the lacquer is water rather than one of the nasty alternatives. Easy cleanup with water and soap, lack of nasty fumes, works great in my airbrushes so very little goes a long ways and goes where you want it not all over the room, same product i use for clearcoating the pedals so always on hand. Can use it inside in the basement in the winter which is when i build, works great with the acrylic paints i use in the airbrushes.
Before getting airbrushes used the spray can lacquer i had on hand for clearcoating, works just as well, no issues soldering through, no need to buy an expensive 'proprietary ' product when chances are you already have something on hand that will do what you want.
dave
Quote from: davent on September 12, 2020, 05:47:57 PM
The heat of the iron vaporizes the lacquer when you touch the iron to the pad, ...
With lacquer, I would worry when applied before soldering. You won't have solvent fumes with the water-based stuff, but you'll get fumes from the lacquer. Probably depends on what kind of lacquer it is, but acrylic fumes are not harmless.
Unless you plan to solder the board immediately or very soon after removing the masking, treating the copper is almost a must.
Trying to solder on to oxidized copper is what will cause loose, cold, or non-existent solder joints. Unless you enjoy scrubbing the oxidation off prior to soldering ::)
Yep the oxidizing is what concerns me. I now leave the etched boards in little ziploc baggies to avoid that. However my problem is exacerbated as my 'workshop' is in my unfinished garage with no climate control - in Texas to boot! I do like the idea of spraying them with something before you start, I'm not on board with what that something is yet. I've got some clear enamel and lacquer I'll try them both...
Quote from: pgodfrin on October 03, 2020, 06:50:23 AM
Yep the oxidizing is what concerns me. I now leave the etched boards in little ziploc baggies to avoid that. However my problem is exacerbated as my 'workshop' is in my unfinished garage with no climate control - in Texas to boot! I do like the idea of spraying them with something before you start, I'm not on board with what that something is yet. I've got some clear enamel and lacquer I'll try them both...
Very light mist coat should be sufficient.
dave
A light coat of clear enamel worked fine! Thanks.
You can coat it with tin right after etching. You can use regular solder, or something special, like Rose's metal alloy (it melts in boiling water, very useful for tinning)
This is the stuff I use
https://www.mantech.co.za/ProductInfo.aspx?Item=90M0056
Kontakt SK10
I spray it on after cleaning off the etch resist laquer, and it is amazing. Helps with soldering as it has flux in it and protects the copper.
I have sprayed it onto plant-made PCBs that were already tinned, helped there too.
MG Chemicals Liquid Tin
You can find it on Amazon.
(https://www.active123.com/ProdImages/421-125ml.jpg)
Quote from: CodeMonk on October 20, 2020, 03:56:02 AM
MG Chemicals Liquid Tin
You can find it on Amazon.
(https://www.active123.com/ProdImages/421-125ml.jpg)
I have tried using this on etched faceplates. The problem that I ran in to was that no matter how much I would clean the copper, the liquid tin would always leave 'water spots' or dark areas on the copper. Aggrivating.
I ran into the same problem with Liquid Tin in that it eventually oxidized on me and i was back at square one. With lacquer no matter how long after i've waited to get to soldering never an issue.
dave
I wrap my bare copper PCBs in seran wrap making sure all the air is out of the wrap. When I'm ready to solder the board, I do it all in one session. After that is done I use flux remover to clean the board and let it dry. After it's dry, I spray the board with Krylon (or any brand) crystal clear spray laquer. It's basically the same stuff as electronics "conformal coating" but cheaper
I always use rosin while soldering anything - it helps me to safe and reliable contacts. And, you can use it before population the desk too, and after it, as a protection layer.
Before: put some strong technical alcohol to smal glass (a few ml) and add rosin, to solve it there, to get laque density. Then use it as laquer at the desk. Let to dry several hours.
After: clear populated pcb desk with soft metall brush, then wash with technical alcohol and again add lacqueer layers with that solved rosin. Very usefull for future soldering too. Cheap and great!