How to make precise sheet metal parts (photochemical machining) 

It always blows me away how you can deconstruct a process to it's bare bones and get a result at a fraction of the cost and you gladly share all your knowledge. You're a true pillar of the community for sharing!

That did not feel like a 22 minute video. Super fascinating stuff! As always, your projects get my imagination going with all sorts of new ideas.

Another neat thing with photoetch is you can do partial depth to make fold lines,like scoring cardboard. Probably needs finer process control,though might be worth trying just putting them on one side .

I'm thinking you could print some markings on the 4 corners of each transparent mask so that you could use a moire pattern technique for easy and clear alignment of the masks when you need to overlay them. I hear this technique is pretty good and can even allow you to quantify the degree of alignment.

Hi Ben, The specialty black inks are great, but if you want to use a regular inkjet then sometimes yellow dye inks can be more opaque to UV light because of UV inhibitors to stop fading. Also a Stouffer Gauge will help a lot working out your exposure times. Cunning Fellow (The guy that did The Etchinator)

So excited every time a new Applied Science video is released!

Coming from someone who has years of photochemical machining experience, your setup and process is pretty spot on. Great job!

For registering the masks/artwork you can get an anti-parralax magnifier or collimating magnifier - they're often used for 4 color printing - look for para-mag magnifier or caprock stripmaster series. 7x or 7 power should be enough.

I work with/design stamped parts and source mesh all the time… Stainless, zinc/tin plated parts and stainless/epoxy coated steel mesh. A lot of our vendors are willing to do stamping tooling on the cheap (

Super cool project It blows my mind that we live in an age where knowledge like this can be shared so easily

This video in a nutshell: “So I figured out a method to revolutionize an industrial process, maybe starting a side business out of it, and here’s the complete technique step by step, so you can be my own competitor” We need more of this kind of heroes like him 😀

The work you put into these projects is completely mind blowing.

"the mess is going to be beyond spectacular" is a phrase that I am going to start using from now on.

One method to improve the density and reduce the pinholes in laser printed output is to use color foils (also called toner reactive film). You run it through a hot laminator or back through your laser printer with the color side against your artwork, and the color film fuses the toner, but not to the areas on your artwork that have no toner. I use it when I am etching PCB's at home. (For PCBs, I print the art on release paper, laminate it to the PCB, then do a short soak in water which disolves a layer of the release paper, allowing you to peel the paper away from the PCB leaving the toner artwork on the PCB. Then I run it through the laminator with color foil which helps with density and pinholes. Then I etch the board w/ ferric choloride.) The color foils don't work with inkjet, though.

The fact he did not keep his knowledge a secret to push his business has just gained me huge respect from me. Keep up the good work

Regarding the transparency and the special ink. I had the same problem 25 years ago making masks for exposing PCB's. Came to the conclusion that printing on ordinary paper worked well enough. The laser toner sticks really well to paper, the coverage is 100% without pinholes. And the UV used to expose the photo resist went through just fine. I had to mirror flip the design so that the printed side of the paper touched the photo resist.

Your idea about a "really clean air source" sounds very familiar to another interest of mine, mushroom farming! They need sterile workspaces and they use large like 2 foot by 3 foot HEPA filter pointed down to create a sterile downdraft area to handle spore prints and gather samples without contamination. They don't even cost all that much, and with a custom hood could make a real nice drying area. I have thought about this for another area I am interested in, beer brewing, as an area to store a kveik ring to dry and keep from contamination.

Ben stuns again with his brilliance and creativity. Did you see how EASILY he defeated that printer's transparency limitation? Loved it.

For more precise alignment (at least during the tape phase), you could use a moiré pattern , possibly with a vernier type setup (so one registration is slightly smaller on one side). Then you could align the interference pattern. Although I’m not sure such precision would be necessary, so you could probably just go with interrupted overlapping lines on the cross pattern (similar to how polymer bank notes have transparency alignment patterns)

I'd recommend replacing FeCl3 with ammonium persulfate. I was happy to finally be able to check etching process at any time.

I love this guy. He makes me happy to be alive.

That magnetic setup on the etching machine is amazing. I could see something like that used for cleaning 3D printed resin parts. This whole video is a how-to start your own photochemical machining company.

Just went through this process and contacted all the vendors you mentioned in the intro for making a few shadow masks for a metal evap tool. Was thinking the whole time this is something I could just do in my shop and it's crazy expensive. Of course I just thought it and you actually did it! I don't have enough demand to build it but it sure would be nice if an OSH-ETCH or SendEtchSend sprang from these efforts!!

Hi Ben, I used to design machines used in photolithography and the photoresists coaters. We used to etch parts on sheets of glass, etching gold and titanium layers. We used to use spin coaters. The nozzles would be placed above a spinning chuck that was made of nylon. The whole thing was surrounded by a big tub with sides higher than the spin axis. The force of the acid falling, hitting the surface and then being flung off was enough at 1000 rpm to take the debris away. For the underside we had nozzles firing the acid up at the underside surface.

In the past I used the head from an photo collimator for a similar UV exposure process where we needed collimated light. Your setup seemed to do the trick just fine, but we needed it to be up close in my application. Its a reasonably cheap way to get get it done as you can fine them second hand. Did have to air cool the lenses as they got a bit hot from the high powered UV light sources :) Mesh bag was a slick idea! Really great video once again

It's almost creepy how you come out with videos that answer the questions that I AM CURRENTLY STRUGGLING WITH. I'm talking about... the same day. It's super helpful, but also unsettling.

If no one else has mentioned it, look at the clean air boxes that mushroom growers use. It might work for drying the metal after cleaning if you’re doing large batches

Couple of thoughts from when I used to home etch PCBs: Laser printing onto tracing paper works much better than transparencies,you nerd to use thick stuff,>90gsm to stop crinkling in the fuser. When aligning the artwork, stapling works well as you can align accurately with the sheets completely flat against each other,but you do need a setup where the staples overhang the edge when exposing, less of an isdue with PCBs due to the thickness of the board

What sort of pump did you find that can handle ferric chloride without disinregrating?

I make circuit boards using laser printer toner for the resist. I use a heated 'laminator' to apply it. My artwork _IS_ my resist. It took a few tries to get right combination of backing paper, heat, and pressure dialed in but it was an inexpensive and rapid process. I purchased the highest resolution BUDGET monocrome laser printer I could find and have much success. I don't know if toner would survive your mesh bagged etching intact though.

Applied Science in five years: "Today I'll show you my home made EUV Exposure Unit for the 3 nm Masks I've developed" Your work is always so amazing!

As others have said, great work as usual X) For the registration alignment of the two layers of transparency - what about using an overhead projector? Put both sheets on the glass, then use the projected image to align the parts. Not a huge amount of magnification, but even 3~5x with good ergonomics would help.

I have been doing a variation of this. Instead of printing on transparencies and then using an UV exposure station I used a cheap resin 3d printer to expose my artwork on the resist. (The kind where a UV light is projected through a digital screen to solidify the resin. I have been using an Elegoo Saturn. I just remove the vat and put the plate on the screen.) It worked quite okay for me. I got some niece pieces. The theoretical benefit is that you have zero setup cost. The very real drawback is that if you want to etch from two sides (and you want to etch from two sides) then you need to flip the plate and place it very precisely at the same spot on the resin printer's screen. To be able to achieve that I have made a kind of jig holding a usb microscope solid relative to the printer. If you do an exposure without the plate being present you can see the invididual pixels of the resin printer with the microscope. And then you can use this to align the second side of the plate very precisely. I have made this decorative orrery using the technique: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KK3TiUWSTbI.html

I really appreciate how you not only show your successes but discuss your challenges in these projects. I have one suggestion if you ever wanted to revisit this. Back in my PCB etching days I found that a viable alternative to spray etching is bubble agitation of the etchant. Putting a fine mesh bubbler grid at the bottom of the tank below the part has similar performance to high pressure spray with the added benefit of not having the etchant running in the plumbing and pump. Both spray and bubbling end up with the same effect of getting fresh etchant to the metal being etched. Just putting the material in a still tank ends up with the etching site having lower concentration of fresh FeCl as the already combined products only slowly move away from the reaction plane. Bubbling seems to have a similar effect as spraying, constantly introducing fresh FeCl to the etch site increasing the overall reaction speed. My first test of this setup didn't anticipate how dramatic the difference was vs simple etchant circulation, so I etched too long and ended up undercutting the mask so much that all the copper was removed from the board! Not quite the result I intended.

I know you can use Miore patterns, which are large macro patterns that naturally appear while adjusting the alignment between parts with fine regular features, to quickly alignment-tune industrial survey equipment *by hand* to a surprising degree of accuracy. (Even to the point where the expensive high accuracy measurement equipment was only necessary as a QC / fine-tuning step, improving production rates etc.) I wonder, if you put a a differently spaced dot pattern on each side of the print if that would enable you to do fine alignment of the two layers by eye ( 13:00 ).

Dude! Awesome. You inspire me to get out in my garage and tinker around. Thanks for letting all of us look over your shoulder while you work on projects!

wow i'm sure that i am not alone in thinking that i'd happily wait months for a vid from Ben. they always all-around perfect. length, audio, video.. then the content.. absolutely fantastic. seeing prototyping is amazing, but seeing Bens prototyping is the epitome of excellence for video. descriptions or ups and downs and gotchas... full of information and helpful and still concise.. WHY IS NOT 1M SUBS YET???

"The mess is going to be beyond spectacular... Okay let's press the start button" 😂

Thank you for uploading. I never do anything particularly useful with the information you provide but you’re always extremely informative and entertaining. I appreciate every video.

As I'm in the process of researching etching, in my case to make data plates, you post this video. Usually your videos send me down a new rabbit hole. It's amazing how much trial and error, research, and practical experience you can compress into one of these videos.

Such elite in-house (literally) mfg capability. Desperately waiting for the applied science 1um IC PDK to drop

You never cease to amaze us with your ideas and projects.

Loved it! And that's probably the most applied science you've shown on the channel

I'm always impressed by your big brain projects and how well you explain them so the layman can still understand the process. I'm retired and will likely never do most of what you show but I really enjoy learning new things and find your projects interesting.

I've gone through almost exactly this process in the last week so this couldn't have come at a better time! I ended up going with a spray photo resist and then removing the resist with a galvo laser since I was making a decorative brass piece but this seems like a fascinating method too! I'm not sure if adding citric acid to the ferric chloride will help with stainless but so called Edinburgh Etch is a more efficient etch used in copper plate print making. The theory being the citrate helps to keep the etched material soluble.

I can always count on this channel to introduce me to a topic or project I have never even considered before and then hold my fascinated attention for 22 minutes. Well done!

The synchronicity of this is just astounding. Yesterday I was looking for this exact thing and found no real good guides on youtube, until I found this - which you uploaded yesterday. Great video!

Great to see this, thank you for your dedication and knowledge

This whole process is very similar to offset printing plates. But they were in aluminum, and only partially etched into the plates for printing. We did quite a lot of these in our class. This was highschool graphics class, back when the 486 was being conquered by the pentiums. We used all Macs though for that class. Don't remember what they were, but early 90's style machines. The large camera is what we used to make our transparencies. Literally a giant wall with a huge lens, and a room behind it to put the transparent film onto it. We developed it right then and there. I bet film transparency would be even better than inkjet as far as detail goes. We then used this on a the plate that was pre-covered with resist, put it in the light bath thing for a few minutes, and then washed it off in a special bath and unknown chemicals (at the time), and then rinsed them, and the plate was done.

Your brain is amazing. And your sharing of your works deserving of many respectful thanks.

Awesome video that breaks down the process and demonstrates some of the quirks of each step.

Regarding the plastic fittings at 19:40, you might want to try Fit-line PVDF or PFA Flare fittings. The PVDF fittings are cheaper and might be all you need. These fitting are more likely to handle the heat, pulsating pressure, and corrosiveness of your fluid.

Very cool! It's quite similar to the process I've used for home PCBs, an Epson inkjet is pretty much mandatory for getting that super-dense artwork-- and yeah, pretty annoying you have to use a piece of paper as a backing to get it to detect the transparency. I use a medium-format Artisan 1430 outfitted with a CISS system to make sure I never run out of ink. Now that Epson has come out with Econo-cart refillable systems it sure makes the whole process straightforward, using special high-density inks. For developer I do like using sodium metasilicate since it seems a bit more forgiving. Also using a vacuum-bag to hold the artwork against the boards is a lot less hassle than getting pairs of glass pieces to sandwich the artwork/board and making sure it has even pressure across the whole piece. For single-sided boards I just use a consumer vacuum-sealer/bag, though I have to make a bag out of heavy plastic tarp for double-sided boards since they have printed stuff on one side of the vacuum bags. To seal them I use the rubber tape which is used for carbon fiber/fiberglass resin infusion, as well as sealing around the vacuum hose. Very easy to use, strong, and virtually leak-proof.

you are putting an entirely new spin on the term "Side Hustle!" Great to follow your work. and as always, thanks for sharing your time with us!

Always great to see an upload from Ben. Very interesting process 👍

Absolutely amazing! Thank you so much for sharing! 💜

For the mask, you could perhaps use a film imager (recorder?) for offset printing. Nowadays many printshops use direct-to-plate imaging, but you may find a used film imager for cheap. The film that goes with it is high-contrast, high-resolution (we used to do 2,400 ppi) and designed for near-perfect registration. Of course, this involves its own film development workflow, which you may not want to fuss with.

Very cool. Very glad to see this work. Amazing that you can do this kind of operation by yourself in a household environment. These are my favorite kinds of video. Can't wait to see what you bring to us next!

Having etched circuit boards, I am impressed by your effort to do large boards and to do so with minimal human intervention.

+1 on another great vid comments :) From a former pro photographer who started in the age of film, a couple of potential resources for old photo tech that could be cheaply adapted: 4x5, 5x7, 8x10 and custom sized sheet film used to be sent through the machines on these stainless steel racks that had standard and adjustable rungs and spacers that would firmly hold several sheets in each rack. The film was held firmly around the perimeter and wouldn’t come loose-I wonder if you could find some of those kicking around somewhere... dunno if Adolph Gasser is still open but they used to have huge piles of photo junk in the basement. I once scored 3 or 4 big enlarger uprights for a song. Hand cranked sturdiness... Also if anyone in your network is closer than Kevin Bacon to any of the good people who worked at the New Lab, buying them lunch in exchange for describing how their big E-6 line functioned would be invaluable, and would probably come with some great stories to boot. One last aside regarding plastic compatibility: I recently threw together an electrolyzer for water-splitting (because BANG!!!) and found the hard way that few plastics do well with strong KOH solutions, including polycarbonate and acrylic-which makes me think of all those electrolyzer kits with the clear outer walls, and how I wasn’t able to find any common clear plastic that was considered to be at all good for long-term contact with strong alkali solutions... I used polycarbonate because it doesn’t shatter but the KOH took it to pieces in days. Anyway thanks for another good episode :) Wells

Thanks a lot. This is exactly what I need to make my miniature parts. I was using tonner transfer for making these small parts but its not that reliable. You can see me using this process in my mini hummer ev video.

Wow, I'm the person the algorithm's working for right this instant - I just switched tabs from a online auction where I'd spent spent about a quarter hour studying the photos for a photochemical machining setup which for sale for about $25k. I just came to the conclusion that it's unnecessarily complicated and expensive for what I can do in my studio given a little patience and slightly more swearing. Of course it would make sense if you needed 60 of something.

Thank you for your content. Its always pushing the boundaries of what is capable in the home shop. You're an big inspiration

Aftermarket photietch for scale models is pretty cool. Also incredibly expensive to buy pre-made stuff so there are inexpensive kits that couple everything for you. MicroMark has a small size kit with everything you need for about 110 dollars (obviously doesn't have a printer included though) Plasmo has a good video on this subject too but it's a lot less precise since it's done on the super cheap with the simplest set up possible

This is how I make my PCB prototypes :) I use immersion oil (for microscopy), between the photomask and photoresist - the edges come out much sharper.

this channel is by far the best applied sciences and engineering channel I have seen. each and every video that is made is detailed to near perfection and the presentation of the work leaves you with virtually no questions about it. thank you for giving us quality content throughout the years.

Awesome, you addressed all the issues I ran into doing the same thing. Your solutions were much better than mine, and well I'm not surprised. Great work Ben! Thanks for sharing

Fascinating project as always, did you ever find a suitable material that could handle the ferric chloride solution?

I can imagine a fully automated system doing all those steps. No wonder why the comercial option is so expensive. Amazing video as always!

Weirdly this is one of my favourite videos from you. I think it's because for the first time you've done something I can actually do in my own shop right now :) But also because it's a process that has many interesting applications. I'm used to doing this for PCBs, never occurred to me to do it on sheet metal. Thanks!

This was awesome I used to be a tool and die maker at Tech Etch in Plymouth MA where they made these type of parts. I love that you just made them on your own. Brilliant

Having refined my own home dry film based PCB etching process, it was really neat to see your variations for doing just metal instead of copper on fr4 or phenolic. The laser printers work pretty well as long as you do two layers of transparencies stacked and aligned, and expose with the toner facing the dry film, at least for PCB usage. Otherwise your process is actually surprisingly similar. I just use a cheap USB aquarium air pump to agitate my (vinegar and h2o2 and nacl) etchant, it's plenty for thin copper clad PCB and a good deal safer than ferric chloride

Incredible that you came up with this whole process.

what is the pumping pressure for the pneumatic pump used in this system? Did you try the technique with only one side exposed? ie etching only from one side?

I'm jealous of how smart and articulate this guy is. I wish more minds were like his.

your vids bring me such happiness, thanks Ben!

Wow, the amount of good information in this video is absolutely huge. But Ben, how are you ever going to start your own succesful etching business if you are telling us all your secrets? ;-)

Have you tried to laser print transparencies and then just use acetone vapor to slightly melt the toner and increase the density? I had some limited success with that a few years back, what you absolutely can't do is let the print for too long on that vapor.

this is BRILLIANT!!!!! You are thew most HARDCORE DIY guy in existence!!!! You make the most amazing projects and you never cease blowing my mind!!! THANK YOU for EVERYTHING you do!!! :D

It is amazing how you optimize a process that is essentially meant to be done a few times. I mean I do a prototype PCBs every now and then but my process is much more manual an tedious then your one time one. You are amazing. Also It is just a best day to have Applied Science and Ben Eater video in one day! Thank you very much for your work.

Is that the anova wifi sous vide cooker? I worked on the wifi backend for that thing! Its cool to see them in the wild.

Nice job Ben! We have used of those services in the past, but now we have a femtosecond laser - your next project? 😂

Thank you for making the video Ben, they're always fun!

very good. great to see problems encountered and solved. I can appreciate the process having made PCBs in a similar (but more basic) manner. ie, the rocking glass pan etcher

"... the mess is going to be beyond spectacular... Ok lets press the start button!"

Custom solder mask here we gooooo

As a career engineer- your projects and abilities blow my mind lmao. Been following since i was in early college and the quality has been stellar for years it’s crazy

every upload is like watching a magic show. and you still tell us how its done and im still in awe

Time to brew some coffee.

Very inspiring. I've made several attempts at chemical etching and not been successful - this inspires me to give it another try.

This may be the best inadvertent ad for Photofab possible. The sheer complexity, wow 🌷🤷‍♀️✅

really fascinating stuff! I'll admit a lot of the finer details went over my head but you did a great job explaining your process.

Wow! Unbelievably detailed with so many great builds. I'm not going to set up my own sheet metal etching business but if I did, it would all be here. Thanks so much.

Ben you sonofa- thanks for releasing another amazing video pushing forward what hobbyists can do in their garages.

the work you do is unbelievable! fascinating as always

Dude, you are one of the most formidably brilliant and capable people I've ever encountered. This process alone by any right should make you wealthy. And this is just one thing you did for a random project... I hope you're rewarded for your endeavors.

I've only ever done basic pcb etching. I thought that was wonderful at the time. This is so many orders of magnitude more wonderful. Brilliant hacky engineering.

So cool. Your work space looks like an evil laboratory especially with the dimmed light. Appreciate the time you must have spent working out this process.

Absolute genius, amazed by every project.

I’ve definitely used paper to back transparencies. I had the same problem. I’m glad you brought it up because I would have had to figure that out again. Yes that was very frustrating.