Can pcb stencils be used as etch stencils? - Page 1
Forum section: electronics / projects

author: krivx
author_rank: Frequent Contributor
timestamp: April 12, 2015, 09:26:23 pm
content: I have been throwing around the idea of etching some text onto some aluminium enclosures. I would like to be able to do small runs of these with the same artwork. The traditional way I have seen this done is similar to etching PCBs, you print the artwork in reverse and in negative with a laser printer and use heat to melt the pattern onto the aluminium, then etch.I'm thinking that laser cut SMD stencils are so cheap, could they work as re-usable etch stencils? Just laser out some text with an appropriate "stencil" font, i.e. no characters with unconnected "islands". I am guessing that stainless steel could be eaten by the etching fluid (??) but is kapton an option? Has anyone tried this?

author: tautech
author_rank: Super Contributor
timestamp: April 12, 2015, 09:56:49 pm
content: Probably better suited to photolithography, use a spray-on photo resist, expose using stencil, develop and etch.For a panel, I'd guess a spray etch sysem would be best.

author: krivx
author_rank: Frequent Contributor
timestamp: April 12, 2015, 10:06:25 pm
content: Yeah but that's messy and a lot more cost than just paying a small amount for laser cut kapton. I am looking for a lazy way to do a bunch of these quickly without any huge setup costs. Photolithography would allow any artwork, not just "stencil rules" though, which would be nice.

author: langwadt
author_rank: Super Contributor
timestamp: April 12, 2015, 10:32:49 pm
content: Quote from: krivx on April 12, 2015, 09:26:23 pmI think it might work with a capton stencil and electro etch; stack part,stencil,etch soaked cloth, metal sheet add some electrocity and see what happens, mind the polarity

author: sleemanj
author_rank: Super Contributor
timestamp: April 12, 2015, 10:36:21 pm
content: Quote from: krivx on April 12, 2015, 09:26:23 pmErr, wouldn't the etchant just seep between the stencil and workpiece and etch everything? The mask needs to completely bonded to the workpiece.

author: Marco
author_rank: Super Contributor
timestamp: April 12, 2015, 10:48:12 pm
content: Quote from: sleemanj on April 12, 2015, 10:36:21 pmIf you're electro-etching with a sponge or something does that matter much, wouldn't most of the etching happen along the shortest electrical path to the metal?

author: Evil Lurker
author_rank: Regular Contributor
timestamp: April 12, 2015, 11:15:09 pm
content: It is possible. But you would have to apply adhesive to the entire back of the stencil to keep the etchant from seeping in between the stencil and whatever it is you are etching. Furthermore the etching is likely to be uneven and or rough looking, which may or not matter or even be desirable. Last but not least the reaction between ferrous chloride and aluminum is well, quitevigorousto say the least and if the hydrogen ever decides to ignite, possibly evenexplosive.

author: rdl
author_rank: Super Contributor
timestamp: April 13, 2015, 02:14:32 am
content: Instead of etching with a liquid just sandblast. I guess you'd probably have to rent or borrow equipment though. Maybe you could find someone local that already does this commercially.

author: Marco
author_rank: Super Contributor
timestamp: April 13, 2015, 09:56:13 am
content: I'd just try to replicate something likethis.

author: Psi
author_rank: Super Contributor
timestamp: April 13, 2015, 10:46:59 am
content: you could probably do negative etching quite easy.put the SMT stencil over the alu and spray some paint through it. So you now have lettering printed with paint.Now etch the plate with some acid so it discolors everywhere except under the paint.Then clean the paint off.Lettering is now in shiny alu and the rest of the panel is a dark discolored etched color.Positive etching would be much harder, since you cant really make a negative text stencil with metal everywhere except the text

author: ajb
author_rank: Super Contributor
timestamp: April 13, 2015, 05:13:31 pm
content: Quote from: Psi on April 13, 2015, 10:46:59 amYou could just stop right there and be done with it. Using paint gives you the option of a wide range of colors, even multiple colors on one part.Alternatively you could look at DIY silkscreen. From what I understand you can do it as a photo lithographic sort of process, so it should be possible to get fairly detailed text and such with a suitably fine screen, and you don't have to worry about islands in letters. Once you've got it setup, it's a one-step process (or maybe two, if you oven or UV-cure the ink), as opposed to a multi-step etching process.

author: krivx
author_rank: Frequent Contributor
timestamp: April 14, 2015, 05:34:54 pm
content: As mentioned, if I go to a paint process I might as well just do a clearcoat on that and call it day.Some good points, I think I might have to order a few stencils and see how feasible this is. It looks like the stencils will cost less than an aluminium enclosure (!) so I'll probably try this on some scrap.