Okay, so heres the deal,
I personally hate solder bridges, but who doesn't. I ordered my first solder masked board and soldered it the other day. WOW what a difference! So, of course, next step was to come here and search for the DIY solder mask. Uh-oh, not possible. Gotta fix that
My theory is that we could, with losts of research, design some kind of solder mask they you apply pre-etching. It would either come before or after the etch resis, it would depend. The thing that makes this possible is that this would be a substance that somehow reacted with the pnp/ink, and is also etch resistant. Meaning that the stuff uncovered by etch resist would stay, and the stuff in contact with the etch resist would react chemically and combine with it. Or, maybe a physical reaction, though im not sure at what temperature ink / PNP melts... and I can't think of any other way to combine the two physically
Anyways, with the ink/pnp and solder mask combined, you could then just remove the two as one with the normal method of scraping/peeling/isopropynol/whatever you use and you are left with is clean copper traces and solder masked board elsewhere
In a perfect world ;)
Anyways, hopefully we can get this to come together, I would need lots of help though. If anyone would be interested in the design of this you can just leave a post or whatnot
© 2007, Zach B.
(Donno if the copyright is applicable, but what the hell it was fun typing it :D )
I've been thinking that this would be easier with press n peel because different inks vary in makeup and chemicals but pnp is (im assuming) fairly universal
I think there is a logic problem here.
Because, if you look closely at a solder masked board, you will see that some of the mask goes over the metal! except for around the holes, where you want to solder to...
So I think the only way would be to paint something over the entire board, that resists solder, and then use a drill of some kind to take off the mask over each pad around a hole.
How about just etching a pcb as normal, then covering the board in wax?
You could just cover the pcb pads in some sort of wax resistant material first? There must be some artists out there?
yeah basically what I was thinking. But not having the traces covered is not a big problem for me. Im talking about the mask that helps prevent bridges. You can always cover the entire voard after with something to prevent oxidation
i think having some kind of mask (selotape? or some kind of brittle paint that wax doesnt like?) on the pads and then dipping in wax or epoxy would be a good way to do it.
doesn't sound like a bad idea :)
How's about this idea.
Etch your board. Clean it up with your usual methods (steel wool?) Then dab a small blob of white glue (Elmer's for example) on to each solder pad. A nice neat and round blob will look best.
Let it dry completely.
Now spray a nice and thin coat of paint onto the solder side of the board. Maybe a transparent color so you can see the traces clearly. Build up a couple of thin coats, just enough to cover the board clearly.
Once the paint is completely dry, wash the board in water. Lightly scrub the solder pads with your fingernails until the white glue dissolves. Bingo. A solder mask that looks clean and professional, and is only a mild p.i.t.a. to do.
© 2007 Roger Lavallee :)
That's a very good idea :)
Only thing is it takes a little bit more work, obviously, as you have to do each pad individually. Also, this would need to be done pre-drilling, as you wouldn't want to clog up the holes. And finally, need to make sure that the glue/adhesive does not leave any solder-resistive residue that could hamper the solder joints
Making some real progress :D
i like the water disolvable glue idea. What about investigating types of glue. i.e is there some kind of solvent you could dip the board into which would remove the glue and therefore removing the "scraping the glue off with your fingernails" stage?
I dont think theres going to be a way of doing this easily without applying some mask to the solder pads before you drill.
i was actually thinking that clear aerosol would be the easiest way to do it, maybe even transparent green/red for a more proffesional look?
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=TESR2501 enamal might be too hard though.
I think a thin coat is the way to go to start off. The thinner the better, as the thicker the mask gets, the thicker the layer on the glue is. You still want to make sure you dont adhere the glue dabs to the board, making them a royal PITA to remove
I think this is one of those things that is no big deal when you're mass producing a zillion boards to be assembled by robots in China, but for one-by-one projects, it's a p.i.t.a. and probably doesn't reap the rewards you'd wish for.
If we're coating the boards to prevent solder bridges, the real solution is just to be careful when soldering, not to mention when laying out your PC board designs. The other benefit of overcoating is that the copper won't tarnish and get dirty/contaminated over the years. I've seen circuit boards I made back in the 80's, which I got my oily fingerprints all over when I made the project, look all tarnished and dirty.
I thought that was why you'd see those E-H boards (and many others) from the 70's which were entirely flowed with solder, covering all the traces.
I still think that for the one-off DIY pedal maker who wants to invest the time into overcoating their boards like some professional boards are done, the white glue/transparent spray paint idea is probably the easiest, especially when you're talking about simple stompbox circuits with only a few dozen components.
The professional way to do it would be silkscreening. That's not impossible, and might be the best way to go if you're trying to repeat the mask over and over. It's also one of the best ways to do white printing on your stompbox, as well as legends on the parts side of your boards. Worth a try, if you're really obsessed with overcoating.
Roger
Yeah -- I think the amount of time and effort spent to solder-mask a DIY board would probably be better spent fine-tuning one's soldering technique...
If you're making your own boards, you also have some degree of control of your solder pads and traces (apart, of course, from ICs, which dictate certain aspects of the spacing). Some adjustments to pad locations and spacing might make soldering a bit easier.
I'd like to second the "learn to solder better" sentiment.
There are some boards where I need solder mask; I recently had trouble unsoldering 0.032" pads on 0.05" centers and getting them clean enough to resolder without using solder wick braid. Anything bigger than that, solder mask is almost immaterial.
Solder mask matters A LOT to a machine that's never going to develop more skill though.
Just fill your PnP image with black excluding the pads and transfer it to the trace side?
Or if you are using DIY layout then delete all the traces and leave the solder pads. With a little image manipulation in photoshop it would be easy to make a mask.
Ex. Delete all the traces in DIY Layout, export the pnp image. In PS, use the magic wand to select all the black color (the pads), expand the select a few pixels, smooth and fill with black. Now invert the entire image. That changes the pads to white. Print and transfer to the trace side of your PCB.
They sell that stuff in a spray can. It's called Conformal Coating, and they usually have it listed with the other chemicals and things that they sell for making circuit boards. I've never used it personally, but I think all you'd have to do is mask off all the solder pads with some tape and then just spray the stuff on there and peel the tape off. I've thought about getting some to spray on my boards after I've soldered everything to keep the copper from oxidizing and getting nasty.
thanks guys
Off topic, but where do you guys buy/get your etchant?
Thanks
I've gotten Sodium Persulfate from Small Bear, and I've gotten Ferric Chloride from Radio Shack. I've gotten good results with both, though I think I like the Sodium Persulfate better because it seems to be a "cleaner" process overall and it's not as nasty to handle as Ferric Chloride. You can usually find all the different chemicals at the different big supply houses as well like Mouser, Allied, Newark, etc...
I recommend purchasing from wherever is most convenient. If you have a local Radio Shack, you may as well try getting some Ferric there so you don't have to worry about hazardous materials shipping. I've never had any problems with stuff like that being shipped other than it usually takes longer because they have to ship it slowly - no airmail for nasty chemicals!
are acrylic enamels satisfactory to do this? my laser engraver comes pretty soon and i'm going to use it to make all my diy circuit boards from now on. i figure it's only one more quick step and a few button pushes to make a soldering mask, so why wouldn't i?
and the colour of course has to be clear-blue :P
anybody know which sprays would work? the only conformal coating that i've been able to find is at RS components and i don't want to order just the one thing, plus it's really expensive...
adding to the (oldish) discussion, the soldering masks would be nice because:
1) protects from bridges
2) makes you lazy... (ermm. that's not good?)
3) protects your circuit from corrosion while still being able to change parts later. if you clear coat a circuit after its populated you need to avoid spraying everything else. and if you hit it with an iron later to change something you make a horrible mess as you burn your way through it. this way you'd spray it even before drilling and only the solderable areas are exposed, which should be covered with protective solder (:
I'll 3rd the "learn to solder better" sentiment. Also make sure your using the proper equipment, new tips, proper wattage, .020 dia.(or less) solder, etc.
Jered
Quote from: Jered on February 21, 2008, 08:31:14 AM
I'll 3rd the "learn to solder better" sentiment. Also make sure your using the proper equipment, new tips, proper wattage, .020 dia.(or less) solder, etc.
Jered
yeah, but you're going to have to spray the board at some point anyway to protect it. so i'm thinking this would be a really good idea. i can solder (: i guess.... i haven't tried smd yet or anything (:
i'm just wondering if anyone knows which paints will work. i guess i'll just have to experiment when the time comes.
This article might be of interest:
http://www.sigcon.com/Pubs/edn/PassivationandSolderMask.htm
I'll second the idea that a conformal spray coating is probably a better idea.
I use clear fingernail polish to paint over the traces. It works great.
Quote from: darron on February 21, 2008, 03:16:23 PM
Quote from: Jered on February 21, 2008, 08:31:14 AM
I'll 3rd the "learn to solder better" sentiment. Also make sure your using the proper equipment, new tips, proper wattage, .020 dia.(or less) solder, etc.
Jered
yeah, but you're going to have to spray the board at some point anyway to protect it. so i'm thinking this would be a really good idea. i can solder (: i guess.... i haven't tried smd yet or anything (:
i'm just wondering if anyone knows which paints will work. i guess i'll just have to experiment when the time comes.
Well then, I use Circuit Coate Uralane 8267. Dries to the touch in 30 minutes, complete insulation in 24 hrs, and fast repair. Just solder through and respray.
Jered
Quote from: Jered on February 21, 2008, 08:05:29 PM
Quote from: darron on February 21, 2008, 03:16:23 PM
Quote from: Jered on February 21, 2008, 08:31:14 AM
I'll 3rd the "learn to solder better" sentiment. Also make sure your using the proper equipment, new tips, proper wattage, .020 dia.(or less) solder, etc.
Jered
yeah, but you're going to have to spray the board at some point anyway to protect it. so i'm thinking this would be a really good idea. i can solder (: i guess.... i haven't tried smd yet or anything (:
i'm just wondering if anyone knows which paints will work. i guess i'll just have to experiment when the time comes.
Well then, I use Circuit Coate Uralane 8267. Dries to the touch in 30 minutes, complete insulation in 24 hrs, and fast repair. Just solder through and respray.
Jered
wouldn't the mask be better if you couldn't easily solder through it?
i'll try some conformal spray from RS components. they have silicone and acrylic. one of the silicones is red though, and they don't mention the colour of the other. i wanted the blue mojo ):
I'll 4th the 'better solder' technique. Soldermask is really for wave solder applications, unless you are trying to do a .4mm BGA by hand or something. If you use less solder, the right heat & have good timing, you'll be fine.
Doing a proper solder mask is equal in difficulty to putting on etch resist if you use photo-techniques. It's much harder if you try some other technique.
The only solder mask technique I know of that's workable at home without either photo or CNC equipment is to put little paper dots on each copper pad, spray the board with lacquer or equivalent, then pick off the dots, leaving the copper pads.
Frankly, learning to solder better is probably going to save you time over the long run.
Historically, solder mask was invented so boards could be wave soldered.
i re-brought this one up because i'm mainly interested in protecting the board. since i'll be using the laser it really won't be any extra work at all to do a solder mask. it would loose the cool diy look but i'd even be happy spraying a clear (? insert paint here that won't make nasty fumes). i don't actually have any problems with soldering or bridges, and the only place where i sometimes get problems is around pads that i made too close, which the mask probably wouldn't help with anyway.
other than the conformal spray, which i'll need to order, i guess it's just something that people here aren't really experienced with. i'll need to experiment to see what chars, what smokes, etc. maybe engine spray...
Circuit Coate is clear.
Quote from: Jered on February 23, 2008, 01:49:42 AM
Circuit Coate is clear.
didn't you say that you can just solder right through it though? will it be happy with populating a whole circuit board? i've never actually used the commercial circuit protectors because i've found anything with high resistance does the trick of protecting from oxidizing, and i always have sprays lying around.
Quote from: darron on February 22, 2008, 07:34:07 PM
i re-brought this one up because i'm mainly interested in protecting the board.
What are you trying to protect? If you are trying to keep the copper from corroding or something like that, then tinning the traces is a good idea. I can't think of anything that would be threatened with the traces tinned, unless there was abuse involved. Assuming corrosion was your nemesis, keeping all of the metal surfaces covered/sealed with the same type of metal would pretty much prevent this because corrosion gets its start where two or more different types of metal are in contact with each other & most component leads are tinned, so tinned traces would even it all out. As long as your tin job was thorough, I foresee no problems.
Quote from: juse on February 23, 2008, 09:53:31 PM
Quote from: darron on February 22, 2008, 07:34:07 PM
i re-brought this one up because i'm mainly interested in protecting the board.
What are you trying to protect? If you are trying to keep the copper from corroding or something like that, then tinning the traces is a good idea. I can't think of anything that would be threatened with the traces tinned, unless there was abuse involved. Assuming corrosion was your nemesis, keeping all of the metal surfaces covered/sealed with the same type of metal would pretty much prevent this because corrosion gets its start where two or more different types of metal are in contact with each other & most component leads are tinned, so tinned traces would even it all out. As long as your tin job was thorough, I foresee no problems.
yes. i meant protecting from corrosion. i guess tinning would look just as cool (:
how do you go about doing it? i saw clip on youtube where he coated the board and then hit it with a heat gun (i have one). i think he used zinc or something for that though. or do you mean just covering the whole board with solder. i suppose i'll check out the electronics places when i am in there next. i like the idea that i could tin it and then leave it forever exposed and solder on it whenever i wanted, so i wouldn't sort of in a rush to get it done that night or the following for example.
i still wouldn't mind trying the solder mask because it should be really easy to do, and i haven't seen a DIY pedal posted here for someone who's done it, and i want to be the first (:
thanks juse
Well you could do it with wave solder machine I think. It's a rocking heated pane with solder in it. When the solder waves passes underneath and every copper that is there is covered. I saw a small machine at the store but don't know how $$.
Perhaps it will help ?
Frank
Quote from: frank on February 23, 2008, 10:30:26 PM
Well you could do it with wave solder machine I think. It's a rocking heated pane with solder in it. When the solder waves passes underneath and every copper that is there is covered. I saw a small machine at the store but don't know how $$.
Perhaps it will help ?
Frank
sounds like heaps of effort to get a board done. but a rocking heated pane also sounds like it would be really useful for etching.
HA HA,
It heats way too much. Imagine the fumes :P
i was hoping that it might come with a thermostat control (:
i once left a whole box in acid to etch in a fridge (not a cold one, i use it for spray painting). half an hour later when i opened it i realised how much fume is actually released. nasty stuff.
I was reading your thing yesterday and it poped out.
Darron I think I have a solution.
My aunt is making Ukrainian eggs for easter. I used to do that also. The principle is that you cover with bees wax the places that will not be dyed. So you have:
- A candle
- Bees wax (sticky) Perhaps you can use something else that cleans out better.
- and a instrument that is a very small metal "funnel" at the end of a stick (some use an used shoelace). there are many hole size in the funnels for different width of marks.
What you do is that you heat up you instrument over the candle and "take a spoon" of wax with the funnel. The wax melt in it and don't flows till you put it against the egg (well your copper pad)
Spray with lacquer and wait it drys
Then heat a bit at low temp in a small oven, and try to take off the wax.
I think you will have to find a good combination of soap/solvent to clean the rest.
I think you could buy all size of those for very low cost on internet.
Keyword: This art is called: pessankas in Ukraine.
I came up with my own tinning process. It's common in the industry - or used to be, before solder mask was common - to roller-tin PCBs.
Did you ever spend any time in the back of a snow-ski rental shop? They have a machine there for waxing skis. It's a pot of molten wax with a large diameter metal wheel which spins slowly above it, dipping the wheel into the wax and rotating above the wax. The wheel gets coated in molten wax - and you just pass the wax-ready ski over the top of the wheel as it rotates. A nice thin coat of wax is deposited onto the ski.
So it is with roller tinning. A metal roller is rotated into and out of a pan of molten solder. The wheel is tinned steel, and carries a thin layer of molten solder on it as it rotates out of the pan. To tin a PCB, you take the freshly etched PCB, paint it with flux, pre-heat, and then just pass the copper side over the top surface of the wheel as it rotates. A thin layer of solder is deposited only on the copper.
The hot vat of solder is dangerous, but I came up with a simpler, smaller process. You go to a plumbing store and get a 6-8" length of heavy brass pipe. At home, you arrange a long handle on the pipe from the middle so the pipe looks like the cross of a "T". You heat the pipe by blowing the flame of a propane torch through the middle. For first prep, sandpaper the outside of the pipe, paint on flux, then heat and tin the pipe with solder.
To use it, you lay your PCB down, copper side up, and paint with flux. Then you heat the brass pipe and load it up with solder, maybe laying a few niblets of solder onto the PCB to replenish. When the pipe is good and hot, well above solder melting, you squeegee the pipe across the PCB copper side. The pipe is coated in melted solder and transfers a thin layer to the PCB. With practice, it's easy and fast, and you don't have to run a solder pot.
I first posted this about eight years ago.
Oh good idea RG,
That is very fun to talk with experienced guys like you. Was there any other solutions that were tested and that worked for some?
Oh maybe it's asking too much! How can we get back that far in time on the subject on this site?
Frank
frank. the wax idea sounds like it would probably work really well. maybe something for Zben3129 to try. i actually want to spray the whole board with a paint and then use the same laser engraver that i made the board with to quickly take off the paint on the pads. all i'd gave to do is modify the original artwork so that it had only the pads and not the traces. the laser takes acrylics, enamels, and urethanes right off the coper and fiberglass. i mostly just wanted to know which paints people use to make the soldering masks. maybe i should have opened another thread, but this was the closest thing in the search and wasn't very old.
R.G.'s idea look like it would be a bit of work to setup, but he says it's pretty easy. I've done screenprinting myself which is a pain so i doubt its as hard as that. it would be good to save those instructions.
i found the youtube video too!
check out what he does at the end of this... he somehow gives it a nickel coating. looks simple enough. anyone ever done that?
http://www.youtube.com/watch?v=8NhNsNw5BfU (http://www.youtube.com/watch?v=8NhNsNw5BfU)
Yes, the wax idea does sound good.
A mask for the solder mask :)
I think you are on to something with the laser engraver, though.
For paint, I reccomend to just try a few options. Try to balance between effeciveness, ease, and cost. I'd reccomend clear, aswell, 'cuz it looks cool ;D
Have fun with it!
Zach
About the "paint", I could search in plastic properties in my technical books. But surely than an experienced guy will give you a better answer. You will want a cross-linking plastic I think, so it won't melt with heat after.
Quote from: darron on February 23, 2008, 11:21:28 PM
i actually want to spray the whole board with a paint and then use the same laser engraver that i made the board with to quickly take off the paint on the pads. all i'd gave to do is modify the original artwork so that it had only the pads and not the traces. the laser takes acrylics, enamels, and urethanes right off the coper and fiberglass. i mostly just wanted to know which paints people use to make the soldering masks.
Hi Darron,
On production boards, fab vendors typically use either green LPI in a silkscreen type method or they use Dryfilm (much nicer looking IMO but not really applicable in your situation), so maybe you could research the LPI for characteristics to emulate for your mask & help you choose a good paint.
What you are doing sounds really cool. So you have a laser, huh? I looked into a small one once & it was about $16,000 so I realized that it was out of my league. You could do so much with one, etch the boards & boxes too. I envy you...... :icon_smile:
Quote from: R.G.
I came up with my own tinning process. It's common in the industry - or used to be, before solder mask was common - to roller-tin PCBs.
R.G. - Very cool method for the tinning. It appeals to my minimalist side.
juse, what's LPI? google didn't give me much useful. i've got some screenprinting ink left over so i'll give that a shot. thanks (:
you can get small lasers from china that start at around 4,000 or so. i got the idea after i got some routing work done. i'm getting an epilog laser though which cost me about $20,000AU. it's getting delivered next week. i've tested it on hammond enclosures and pcbs to make the mask for etching. VERY quick and easy. i also cut a small scratchplate from wood in about 20 secs. a few things that i was thinking of doing for DIY stuff was making some of those plexiglass bottoms that popped up in the pictures thread. if people had ones they could buy that perfectly fit then i think they might want them. i'd also consider etching the B and BB enclosures, i'm not sure if it's worth my efforts though. if it's one every now and then for people it would be alright. if i do the mask and they do the actual etching themselves then it would be heaps easier (:
Quote from: darron on February 25, 2008, 01:29:23 AM
juse, what's LPI? google didn't give me much useful. i've got some screenprinting ink left over so i'll give that a shot. thanks (:
Sorry, LPI stands for Liquid Photoimageable. If you ask Google about that he'll tell you more than you ever wanted to know!
The laser I considered getting was the Epilog Mini 18. Nice machine. I can't justify it unless I was to go into business for myself with it. So, I'm stuck with the liquid etching. Be sure to post some of your stuff when you get it up & running. You'll probably etch everything in the house when you first get it. :icon_smile:
the mini 18 is what i'm getting. it actually won't really etch aluminium, and DEFINITELY won't dent copper in the slightest. it won't even cut through fiberglass because it sees the glass as a mirror and bounces most off it off. same with the copper. so i'm still going to be using the acid. the fact that it doesn't burn off the copper is what makes the soldering mask possible, i could paint on the copper and laser it and the copper will remain perfectly intact, undamaged. their fibermark machine does metals, but i'm not going to buy a laser just for a little diy hobbie of mine... if i was in production i'd consider it, but even then it wouldn't be worthwhile. you bet i'm going to etch everything in my house!!! once i've got a bit of practice i'll even shove my mac book pro under there. if you youtube it, you'll see that there's so many more applications than you can think of. still, i'll need to find ways of doing boring stuff to help the machine pay for itself. i'll need to find the spare time to do it, but the plexiglass etc, will be some idea i'll want to do. i'll take a look into LPI. thanks! (:
Quote from: darron on February 25, 2008, 01:29:23 AM
... i'm getting an epilog laser though which cost me about $20,000AU. it's getting delivered next week...
Holy Moley, Batman! :icon_eek:
How many PCBs can one buy for $20,000 AD?
Here is my tonights experiment.
(http://img408.imageshack.us/img408/2979/transistortesterux8.jpg)
By jpm83 (http://profile.imageshack.us/user/jpm83), shot with Canon PowerShot A70 (http://profile.imageshack.us/camerabuy.php?model=Canon+PowerShot+A70&make=Canon) at 2008-02-25
I first fluxed the board and them melted a blob of solder to the tip of iron and then transferred the solder to the used desoldering wick and run that over the traces and pads.
Janne
Quote from: jpm83 on February 25, 2008, 11:35:21 AM
Here is my tonights experiment.
I first fluxed the board and them melted a blob of solder to the tip of iron and then transferred the solder to the used desoldering wick and run that over the traces and pads.
Janne, I do believe that would survive a nuclear blast!
One thing to keep in the back of your mind while tinning traces by hand with a soldering iron is to move as quickly as possible to keep from lifting traces or pads. Copper peels off of the FR4 pretty easily when coaxed by heat.
Another tinning method is called
Skillet Reflow, if you can find some solder paste: http://www.opencircuits.com/Skillet_reflow. You can even use a toaster oven for this one.
When I have a tight layout, I just take an awl (pointed tool) and just scratch away the PNP from the solder pads and leave the PNP on the traces. Works really well for preventing solder bridges plus it smells good when it burns! After you are done you can just leave it and it will eventually all come of or you can spray it with something to keep it on there. I usually just leave it.
I've also heard that some put a "lacquer" over the whole pcb (even the pads). Then when they solder the components, the lacquer melts and act like flux. Sure it will not help quick soldering over the pad only but the copper traces will be protected. I would really like to know what kind of "lacquer" should be used there cose I've tried it on ROG "fet 18" with acrylic lacquer and it was hell of a job to heat an off as to go trough it. I finally had to clean all that mess and start all over. Well if you know what kind of lacquer tell me. :icon_confused:
Darron,
I have searched in my mess and found what I had talked of before to you. My aunt use the same device but it is a no mess "included in the funnel" electric device (instead of heating with a candle).
(http://i260.photobucket.com/albums/ii36/frank_peltier/diystompboxes/waxpads.jpg?t=1203972073)
Now, note how precise "ARTWORK" you can do with those babies. All are step-dyed with that wax process. This is my collection:
(http://i260.photobucket.com/albums/ii36/frank_peltier/diystompboxes/EGGS.jpg?t=1203973591)
Low tech savoir-faire.
Mhh Think I'm gonna try that on a new project.
If I do this it would be to protect the circuit, rather than avoiding bridges. Could you (yes, its a pita) use the stuff to paint nails to protect the circuit?
R.G., I guess you could probably buy like a billion! haha. but it's not a pcb makin' machine. that's just some of the abuse it's going to cop.
the skillet reflow method sounds pretty similar to what was in that youtube clip. did anyone watch that? i'll report my finding on which paints stink soon.
thinking about it, i pulled out an old board i made about 2 years ago which i clear-coated over. i think i used a polyurethane (years ago). all of the traces are actually a dark-ish tarnished brown. maybe it's just the surface, i suppose its not going to get worse and the copper won't deteriorate.
those are some mighty fancy eggs! apply that practice to an enclosure and you've got a respected spot in the pictures thread :D
By the way, the green corrosion on the copper IS PROTECTIVE. That is why so many roofs are made of copper and lasts so long. Just make sure there is not much flux left. after your board is finished. The green/brown copper oxide will protect the copper trace because it create a seal against oxygen penetration. That is also why bronze statues lasts for 100 of years, On iron it is not the same thing, ferrous oxide is not a tight protective layer against oxygen.
Quote from: frank on February 26, 2008, 12:43:00 PM
By the way, the green corrosion on the copper IS PROTECTIVE....
The green patina may look good on a roof, but not so much in an electronic circuit. My issue with it is that it interferes with future rework by possible contamination of the new solder. I suppose you could buff it off before you resolder, but then you risk ripping up a trace or pad & it is just an extra step I'd prefer to avoid. I would rather protect my circuits with something I can control, like tinning. But, I guess the patina could give a certain vintage vibe.....
Quote from: juse on February 26, 2008, 02:24:59 PM
Quote from: frank on February 26, 2008, 12:43:00 PM
By the way, the green corrosion on the copper IS PROTECTIVE....
But, I guess the patina could give a certain vintage vibe.....
AAAHHHH AH ...JUSE... Now, you really got to start a myth with this one. Sure some will believe it.
Quote from: frank on February 25, 2008, 01:56:33 PM
I've also heard that some put a "lacquer" over the whole pcb (even the pads). Then when they solder the components, the lacquer melts and act like flux. Sure it will not help quick soldering over the pad only but the copper traces will be protected. I would really like to know what kind of "lacquer" should be used there cose I've tried it on ROG "fet 18" with acrylic lacquer and it was hell of a job to heat an off as to go trough it. I finally had to clean all that mess and start all over. Well if you know what kind of lacquer tell me. :icon_confused:
Here in Europe, the company Kontakt Chemie is widely known for a lot of different aerosol-based cleaning/protecting/etc stuff. They make something like what you described, which you can see here (http://www.crcind.com/csp/web/ProdDisp.csp?lng=3&country=ALL&product=FLUX%20SK%2010&brand=KOC).
Probably not available outside Europe, but you could look at the ingredients to see if you can find something similar.
They also have some sort of acrylic lacquer (http://www.crcind.com/csp/web/ProdDisp.csp?lng=3&country=ALL&product=PLASTIK%2070&brand=KOC) which they say can be soldered through, but it sounds a little nasty to me.
Quote from: frank on February 26, 2008, 03:33:39 PM
Quote from: juse on February 26, 2008, 02:24:59 PM
Quote from: frank on February 26, 2008, 12:43:00 PM
By the way, the green corrosion on the copper IS PROTECTIVE....
But, I guess the patina could give a certain vintage vibe.....
AAAHHHH AH ...JUSE... Now, you really got to start a myth with this one. Sure some will believe it.
MXR is already going down that road with their fuzz face advertising:
http://www.jimdunlop.com/index.php?page=products/pip&id=359&pmh=products/p_and_e_detail (http://www.jimdunlop.com/index.php?page=products/pip&id=359&pmh=products/p_and_e_detail)
Quotet is authentic in every detail - a handwired brown circuit board with no solder mask and circuitry carefully matched to the original specs.
Oh! The the industry is very competitive, I see....
Seymour is selling beaten up PAFs, Marshall is selling cabs with teared down grillcloth and perforated speakers, and Fender is selling tribute Keith Richard teles with completely burned headstock by cigarettes.
Soon they will be selling us worned to the bottom picks.
So Darron, you understood the lesson, (stare at Dragonfly's whrils).....no more solder masks....no more solder masks....
My wax pad masks took me 15 min. to do on the ROG Eighteen ;D.
But I am stupid and sprayed polyurethane :icon_confused:.
Well, should have thinkd before, that bees wax is soluble in those solvents :-[.
I should read more psychology mag and listened to my little intern voice (it said don't do that idot) :icon_redface:.
before = :):
(http://i260.photobucket.com/albums/ii36/frank_peltier/pad_masks/xax18pads.jpg?t=1204937280)
now = :'( :
(http://i260.photobucket.com/albums/ii36/frank_peltier/pad_masks/badwax.jpg?t=1204937646)
Conclusion: water based lacker should be OK.
i've bought two sprays to play with. one is a small can used to spray glass (which is what the pcb is anyway), which is a semi-transparent blue. it doesn't say what it is made from. i tried it on a pcb and it worked great. the solder didn't seem to bother it and the flux just melted over the top of it. the other is a candy-apple red which worked jsut as well, but cost 4x. blue looks prettier too.
i'll try to get some pics up of a properly populated board and solder mask.
I have removed the wax. At some pads the limits are very neat. But at other places, big chunks of polyurethane pealed off. What a mess.... breaks my heart to throw that PCB in the trash. Gonna take a break I am :P .
Did not work with water based acrylic neither. The wax was trapped underneath the layer of paint. When The PCB was put at heat so the wax could melt, the acrylic stayed there. When I rubbed a bit to remove the hot wax, everything started to lift and peal. I think my experiments are going nowhere.
Would this be useful in this thing? http://www.dickblick.com/zz217/11/
Janne
Quote from: jpm83 on March 08, 2008, 08:51:23 AM
Would this be useful in this thing? http://www.dickblick.com/zz217/11/
Janne
probably as useful as any other clear. if you've got some then give it a shot? (:
The thread sealant used on water and gas piping is impervious to water and petroleum solvents like paint thinner and such. It dissolves in alcohol.
A useful technique might be to use a brayer to roll a layer of this gook onto a sheet of window glass, then use the eraser on a wooden pencil to stamp a round "not here" covering on each pad of the PCB. The passivating spray could then be one impervious to alcohol and you could wash off the pad coverings with alcohol.
Still a lot of work.
After my bad experiments, I think that what would perhaps work, would be a kind of alcohol based lacquer or shellac.
One thing that is sure is that the paint should:
1- Contain no solvents that can dissolve wax
2- Can be sprayed as thin as possible
3- Once dried, would be "brittle" so it could break easily around of the wax "islands" when the wax is removed.
If you think of something tell me, I cleaned the "testing PCB".
Do you think that instead of the wax you could put finishing nails in the holes? The head of the small nails would act like small pad masks. Then you spray and remove the nails. It would also be faster......no ?
toothpaste/spraypaint?
One thing that crossed my mind is to use a hole punch http://upload.wikimedia.org/wikipedia/commons/a/a5/Hole_punch.JPG to make small sticky pads from contact paper
http://housewares.hardwarestore.com/37-188-contact-papers/clear-contact-paper-105240.aspx and put those on the pads.
Janne
Quote from: MarcoMike on March 08, 2008, 01:39:29 PM
toothpaste/spraypaint?
Is it a tested advice or I will screw up again.
I don't know about you, but I will *always* screw up again. :icon_lol:
well, it was just the first (maybe second) idea that came through my mind...
the first one was some kind of cookie dough... any sticky, water-based material....
thinking back to it, cookie dough looks even more promising: you can bake it after painting and its expansion may help the separation step...
do as scientists would do it: find several masking materials, apply them all on the same sample, spraypaint the sample and see which one works better, you may screw up only once!
I think I am at the "finishing nail option" step. After that I will have the hammer in my other hand...
Quote from: R.G. on March 08, 2008, 09:39:47 AM
The thread sealant used on water and gas piping is impervious to water and petroleum solvents like paint thinner and such. It dissolves in alcohol.
A useful technique might be to use a brayer to roll a layer of this gook onto a sheet of window glass, then use the eraser on a wooden pencil to stamp a round "not here" covering on each pad of the PCB. The passivating spray could then be one impervious to alcohol and you could wash off the pad coverings with alcohol.
Still a lot of work.
Oh no Mr Rg,
you gave me a new idea.
Think that it is my destiny to pass trough this mask karma.
I know I'm resurrecting an old thread, but Humiseal makes a solderable conformal coating. Etch/drill your pcb, spray it, let it dry, start soldering.