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Dying PCBs vs. Solder Masking PCBs

TheLaw

Sep 27, 2010
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Hello,

I am new to the forum so, hello! For one, I like to say that I enjoy the aesthetics of the site and it is a relief to some of the bland white ones I have been lurking around on.

Anyway,

I have a question that hopefully someone would know the answer to. I'm going to be etching some basic boards for some projects I am going to do for fun. Some audio circuits, LEDs, and other simpler things. Nothing too complex.

So, I was on Youtube and I saw some people dying their homemade PCBs in clothing dye like RIT. They turned out pretty nice!

But I am pretty confident they are not just dying PCBs in large scale manufacturing. I believe they use solder mask.

So,

1.) Does solder mask have any advantages over dye? (For DIY projects is solder mask nessecary?)
2.) How does one apply solder mask? (Lamination machine?)
3.) Anyone know any solder mask suppliers that have multiple colors?

I'd really just like to dye it but if that's not good or has disadvantages, I'll have to research some more.

Thanks in advance!
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Perhaps if you can give us a link to the youtube video(s).
 

Militoy

Aug 24, 2010
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Solder mask isn't technically necessary for a home-made or prototype PCB. It's designed to make soldering possible in a production environment. I don't even bother with etching for prototypes - Instead I lay out a simple pattern on CAD - then paste the paper on my copper-clad board, and cut between traces using a Dremel tool. I flow solder over the entire board before starting to add components. The result isn't as pretty as one that's been dyed with RIT - but it's quick and gets the job done. Matter of fact - doesn't fabric dye have salt as it's main ingredient? Don't think I could get too excited about dunking my PCB in salt water! If you are using small SMT parts and need fine pitch resolution - then you're stuck etching. Liquid solder mask is available in a variety of colors - both in bottled form and in convenient touch-up pens. Just don't mix up the liquid photo imagable (LPI) type with flexible solder mask. The flexible kind is like rubber - made to keep solder out of specific areas during multi-step wave soldering operations - and then to be peeled off.
 

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TheLaw

Sep 27, 2010
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Well I'm not saying either way. I'd just would like to add a little bit of color instead of having that bland tan-ish yellow color. The most important part is functionality but looks are also important.
 

(*steve*)

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I've just discovered "Cool Amp Silver Plating Powder". Someone suggested it as an option for coating boards as it doesn't deteriorate like some (many?) tin coating solutions.

One bottle was quoted as a "lifetime supply for the hobbyist".

And the video showing dying of pcb's did show the colour solution being salty. Not sure I'd want to add salt to my boards...

Anyone heard of it or used it?
 

TheLaw

Sep 27, 2010
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(*steve*) have you ever used or heard of Liquid Tin? (http://www.mgchemicals.com/products/421.html)

TheLaw did you see the second video where the board was dyed using permanent markers?

Yes I saw both but its seems more professional to dye them. Either way. :D

Thanks. It would seem that permanent markers would get expensive and the coloring would be inconsistent if I made perhaps more than one in the future.

Oh and salt + circuits does not mix?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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No, salt and electronics doesn't mix.

You'll find lots of dissimilar metals, mix that with salt, humidity, and a potential difference and you will get accelerated corrosion. Added to that you will also get increased leakage across the board. That may matter less for simple circuits.

I'm not sure why you think its professional to dye boards.

I'm also not convinced it would work on fibreglass boards. It seems the dye technique is used on cheap and nasty boards.

In contrast, tinning of the board has a definite purpose.
 

Militoy

Aug 24, 2010
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No, salt and electronics doesn't mix.

You'll find lots of dissimilar metals, mix that with salt, humidity, and a potential difference and you will get accelerated corrosion. Added to that you will also get increased leakage across the board. ....

Even if you are successful getting the circuit to work initially - there will be residual salt that's sure to be left behind. Your pretty, dyed PCB could very well be running right along - fat, dumb and happy - until you have a series of humid days that leave moisture behind. The residual salt turns to brine - and your circuit goes to pot. A related issue is the dye itself. Multi-purpose dyes like RIT are classified as "self-leveling acid" dyes. Add an acid compound to a salt carrier - and I definitely am not interested in the bright color.
 

TheLaw

Sep 27, 2010
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Even if you are successful getting the circuit to work initially - there will be residual salt that's sure to be left behind. Your pretty, dyed PCB could very well be running right along - fat, dumb and happy - until you have a series of humid days that leave moisture behind. The residual salt turns to brine - and your circuit goes to pot. A related issue is the dye itself. Multi-purpose dyes like RIT are classified as "self-leveling acid" dyes. Add an acid compound to a salt carrier - and I definitely am not interested in the bright color.

Well I've come to the conclusion that coloring a board is not really worth it. I'll definitely tin it but that's it. Maybe I'll find something else to color it with.

Thanks.
 

TheLaw

Sep 27, 2010
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Even if you are successful getting the circuit to work initially - there will be residual salt that's sure to be left behind. Your pretty, dyed PCB could very well be running right along - fat, dumb and happy - until you have a series of humid days that leave moisture behind. The residual salt turns to brine - and your circuit goes to pot. A related issue is the dye itself. Multi-purpose dyes like RIT are classified as "self-leveling acid" dyes. Add an acid compound to a salt carrier - and I definitely am not interested in the bright color.

Well I've come to the conclusion that coloring a board is not really worth it. I'll definitely tin it but that's it. Maybe I'll find something else to color it with.

Thanks.

On another note, does anyone have an reccoendations for LM386 alternatives. Amps/Op Amps that can be run off battery?
 

(*steve*)

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Why do you need an alternative? It's probably not supply issues since findchips.com tells me it's super common.

Is it the power consumption? There are some cheap(ish) "Class D" amplifiers available from China. You can get the ICs from them too, but the little boards are probably cheaper than you could make them in small quantity. (just watch the output power rating -- it's based on 10% THD).

Or is there some other reason?
 

TheLaw

Sep 27, 2010
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Why do you need an alternative? It's probably not supply issues since findchips.com tells me it's super common.

Is it the power consumption? There are some cheap(ish) "Class D" amplifiers available from China. You can get the ICs from them too, but the little boards are probably cheaper than you could make them in small quantity. (just watch the output power rating -- it's based on 10% THD).

Or is there some other reason?

Power consumption isn't an issue. I just was looking for something that could put out a little more power than the 386, but I'm just starting in audio electronics, so I'll just try to figure out the dos and don'ts of audio first, and then I'll go from there.

Thanks.
 

(*steve*)

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Sorry, I misread your initial request as being for an LM380, not an LM386.

So the answer to your question is... An LM380 :)

An LM380 is a 2.5W audio amplifier, very easy to use, and the bigger brother of the LM386.

Sorry about that.
 

TheLaw

Sep 27, 2010
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Sorry, I misread your initial request as being for an LM380, not an LM386.

So the answer to your question is... An LM380 :)

An LM380 is a 2.5W audio amplifier, very easy to use, and the bigger brother of the LM386.

Sorry about that.

How suitable is it for battery operation?
 

(*steve*)

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What sort of batteries? Fine for car batteries, not fine for hearing aid batteries. Results will vary in between and will also depend of the load you want to use.

Check out the specifications (for the LM380 *AND* the batteries you intend to use) and the answers will be revealed.
 

TheLaw

Sep 27, 2010
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What sort of batteries? Fine for car batteries, not fine for hearing aid batteries. Results will vary in between and will also depend of the load you want to use.

Check out the specifications (for the LM380 *AND* the batteries you intend to use) and the answers will be revealed.

I was hoping like 2 9V batteries in parallel or something.

I'll go check the datasheets
 
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