Stupid question about etching

[ppatchmods]

let's say i have a certain board that i etch a lot! do you think it would work to get a rubber stamp made of the transfer and stamp it on the pcb to etch it? any thoughts?

[jkokura]

what would the cost of getting the stamp made be? If it works how many boards would it take to cost you less than the alternate method? If it doesn't work, does the 'throw away' money of the experiment deter you?

I think it's a valid idea to research if the dollars and cents work out. If it's 20 bucks to try, after 10 boards it becomes cheaper, and if it fails it's 'just 20 bucks' then go for it. If it's 150 and it takes you 150 boards for it to be worth it and you say, "whoa, if this doesn't work and I spent 150 bucks for nothing" and get really mad at the thought - wait until someone says "i've done that and it works great" before thinking too hard.

[Minion]

Well if you are willing to get a rubber stamp made them you might as well just get a silk screen made and know that it will definately work ......  Cheers

[synthmonger]

let's say i have a certain board that i etch a lot! do you think it would work to get a rubber stamp made of the transfer and stamp it on the pcb to etch it? any thoughts?

Sounds like a good idea. Maybe you could etch a board in reverse and try to use that as the emboss to stamp with?

[Mark Hammer]

What would you stamp on that would resist the etchant?

Not so sure it is a good idea even if you could get the stamp made cheaply and find some etch-resistant stampable substance.  The principle reason would be that broad ground areas would not likely transfer very well.  That is, you'd get the border of the ground area, but a ratty-looking area inside the border.  Traces and smallish pads would likely come out okay, but the wider/broader the area, the bigger the risk.

As Minion suggests, a silkscreen process is probably the better choice.  I don't think it is a stupid question to ask, though.  It's just that the answer wasn't what you wanted.

[ppatchmods]

i already use ink that is very resistant to rub off and water for some graphics. it's that stazOn ink. i understand the hesitation. the stamp is about 35$. how much is a silk screen and what is involved in that method?

[Mark Hammer]

Well, then it may well be possible to do what you want.  I openly confess to knowing less about what is available in the way of usable stamping substances than other folks like yourself.

I still think the risk of having blotchy ground planes remains, but if you are OK with simply having traces and pads, with no broad copper areas, and reasonable spacing between adjacent pads or adjacent traces, then a nice thick ink could work well.  Hopefully, it won't distort the spacing in any way.

Personally, I think that you should not sell PnP short.  Assuming the board layout is not too large, you can squeeze a surprisingly large number of layouts on a single sheet of PnP or photo paper.  Then you can either etch the whole sheet of copper board at once and cut boards as you need them, or cut up the PnP/photo-paper sheet and use up layouts as needed.   A great many of the well-loved circuits here would be able to fit on a $2 sheet of PnP some 30-36 times with little difficulty.

[sean k]

I got a bunch of rubber stamps made a few years ago but it wasn't for the rubber stamps but for the intermediate processes to get the stamp. The guy did it the old fashioned way and used a heat and press kind of methothod where he used a basic photo resist on the artwork which created a thin metal plate white a resiny materail raised up and he then applied this to the rubber which when heated and pressed fit around the resiny metal plate. The resiny plates were what I was after as I could mold a two pot molding resin from them and create badges that could then be cast in pewter or zinc etc.

The point being that if you understand the process you can usually get what you want somewhere in there. It would depend on how the rubber stamps are made and if it's the modern method then can you have them cut the traces deeper and can you get a harder rubber compound and be then doing something like lino cut printing... actually lino cutting might be better for what you want as a printing method.

As for screen printing, which I've never done, but I've been close to others who did it on T-shirts, the artwork ( a doubled photocopy on acetate) is taped to the bottom of the screen which has a photo emulsion on it then the whole thing is placed under UV light then the areas that are clear are washed away in water. Making up screens is pretty staraightforward and learning to print them isn't beyond most peoples capabilities... just leave enough room at the top of the screen to put the ink in.

I haven't gotten around to it but I've got some textile ink that I'm going to coat a board with then draw on and scratch away the areas I want to etch. The inks cheap and I may get away without heat setting it before etching... Experiment and you learn, watch others and you learn more!

[rock_god_dan]

Given that you've found the right ink, I'd say that would work. I've been etching with a pentel pen marker ever since my laser printer broke down, and it's been alright. Just make sure you got the ink in, with no "thin" areas...the ferric will still etch through that 

Dan

[Ice-9]

I would suggest if it's a board you make quite a few of, then why not just do a one off print onto clear acetate or tracing paper with a laser printer ( no matter how many boards you want , you only need to print once) and buy an 8 watt UV tube at about $8 and use photo senstive pcb which is only slightly more expensive than copper clad pcb. Better results and cheaper.

[Taylor]

If you're doing a lot of them, get some professional PCBs made. They are really not that expensive if you're doing a lot of the same board. It's technically much cheaper if you consider that "CEO you" is paying "laborer you". And "laborer you" is probably working for much less than minimum wage if you think of it this way.

If you don't need silk screen and solder mask, boards can cost about 2 dollars apiece from fab houses in reasonable quantities.

[R.G.]

Congratulations. You have reinvented the stamp pad system for making PCBs. There was a commercial product which did exactly that some years ago.

[solderman]

Hi
Use the fotoresist method and print a A4 with a lot of the same PCB templates and use an A4 cupper with fotorestistent. Etch them all together and devide them after the are ready. I wold hate the drilling though 

Or the wisest thing is to have them made professionally. It's a economically good idée at 10ps already