What's the latest greatest DIY PCB etching method? - Page 1
Forum section: electronics / general

author: Labrat127
author_rank: Contributor
timestamp: September 24, 2025, 04:55:43 pm
content: Greetings all!I've never chemically etched a PCB myself - 99% of the boards I designed were professionally fabricated, 1% were created by a PCB miller. But I can't resist the temptation of a same-day turn DIY PCB fabrication at home. For those of you who have experience with chemical etching, what's the best method nowadays? I'm talking about, say, a two-layer board (no larger than 4"x4") with a handful of vias, 0.25mm minimum track width, 0.25mm clearance. To me, quality is probably the most important. Cost should be no more than 20 USD per board. No crazy chemicals that can easily cause dangers.Thanks for sharing!

author: Uunoctium
author_rank: Frequent Contributor
timestamp: September 24, 2025, 05:25:55 pm
content: Last and probably outdated information, i knew (> 20yrs):fast and best results with FeCl3 + H2O2 in spray etching machines

author: CatalinaWOW
author_rank: Super Contributor
timestamp: September 24, 2025, 05:35:23 pm
content: To my knowledge there are no processes which meet your requirements. All enchants technically require disposal as hazardous materials, though some are worse than others and some jurisdictions are lax enough to allow more casual disposal.That said, when I etch (rarely) my own boards I use hydrogen peroxide with HCl due to ready availability of the materials. I do toner transfer and have been able to meet the specs you set. Hole drilling for any through hole components you use is a big issue. I have never gotten good accuracy on these. Doesn't matter for older two terminal devices like resistors, but for things you are more likely to need, connectors, transformers and the like it is hard.Finally, same day turn around is feasible, once you have everything in place. But it will take a large part of a day after all the steps are run through.Which is why I rarely do it. Most will advise never.

author: tooki
author_rank: Super Contributor
timestamp: September 24, 2025, 05:39:04 pm
content: Quote from: Labrat127 on September 24, 2025, 04:55:43 pmFirst off, please don't use custom font tags gratuitously. Courier is way harder to read than the forum default, but moreover, override any settings the user makes, which they may need for accessibility reasons.As for etching: I don't think there have been any big innovations in etching chemistry or processes for many, many decades. You mask the PCB however you prefer (photoresist, toner transfer, etc.) and then etch. The classic etchant, which is said to produce the best results, is ferric chloride, which is still easily obtained in USA.Does it count as a "crazy chemical"? Dunno, that's a very sloppy, imprecise description. To some people it would be, to others it's peanuts.

author: Uunoctium
author_rank: Frequent Contributor
timestamp: September 24, 2025, 05:45:47 pm
content: I like to add some information from BEL (Bungard Electronic) a small compay located in Germany. Produces spray etching machines and delivers all consumables for lab size and small series PCB production.Consumables:https://www.bungard.de/en/consumables/consumables/chemicals-and-accessoriesMachines:https://www.bungard.de/en/machines

author: Labrat127
author_rank: Contributor
timestamp: September 24, 2025, 08:03:30 pm
content: Thank you all for the advice so far, including the font use. There're some Youtube videos that demonstrate the process. There're a few different approaches. I figure for someone who is actively doing this, he/she may very well know these approaches and the pros and cons of each. So I thought I'd just ask the question here, hoping someone would point me in the right direction. For example, what's the best way to transfer the artwork to your board to form a mask (forgot what that process is called), and what's the best way to etch the board (material, process, heads-ups, etc.).The dead bug prototyping approach is fast but sometimes hurts the layout parasitics. To me, the DIY board etching is a step up in that direction. By "crazy chemicals" I mean chemicals you need to treat with extreme care. For example, concentrated sulfuric acid, or something that hurts if you inhale even a tiny bit. Things like that. Thank you!

author: CatalinaWOW
author_rank: Super Contributor
timestamp: September 25, 2025, 02:39:21 am
content: The perceived danger of the chemicals varies widely, and I consider it dangerous to identify yourself in a public forum advocating procedures which will draw the ire of environmentalists and legal authorities.The key is to not offend anyone whose standards are stricter than you personally feel are appropriate. Either by not doing it or not getting caught. The penalties for getting caught range from public shaming to large fines and even jail time.There are two main at home processes for transfer of the design to the board. Maybe three. The third is to get a resist pen and hand draw the circuit on the board. Works for simple circuits and some people.Toner transfer is using a laser printer to print the gerber layouts from your ECAD program of choice (in mirror form) on a suitable substrate. There are commercial transfer papers available and some photopapers work. Once upon a time people used magazine pages, but that whole industry has almost completely disappeared and the currently used paper is less satisfactory. This print is then ironed onto the carefully cleaned board using a common household iron. The toner melts and adheres to the copper. When all works right the resulting sandwich is soaked in water and the paper peeled or rubbed of leaving the toner on the board as resist. There is a lot of process tuning in this, picking the right paper, the right settings on the laser printer, the right heat and time for ironing and finally getting the paper off. Once mastered it works fairly well, and can handle the size boards you describe.The other common process uses photosensitized boards (purchased commercially) or a spray on photoresist. The boards need to be protected from light until used. The gerbers are printed on transparencies (getting less commonly available now that overhead projectors have been replaced by video projectors) and contact printed - placed next to a photosensitized board and exposed to enough light the expose the photoresist. You need to choose positive or negative resist and print the gerbers appropriately. The hardest parts are usually forcing the transparency against the board and getting the light source (often UV) and exposure time sorted out. Again, once you have dialed in a process it will work over and over, but the initial set up can take a while.Etching involves similar set up issues. Even etching requires some sort of agitation or stirring. Both horizontal etch tanks and vertical tanks have their advantages and disadvantages. For etching to occur in less than hours you usually need to heat the etchant. Vary with many factors and you will have to figure out for your set up.One thing often overlooked. You mention double sided boards. There are kits to help you plate holes to create side to side connections, but it is one more process to tune in. I haven't personally tried it, but know of those who have both succeeded and failed. Another common approach is just soldering a short stub of wire into the whole (after arranging an appropriate pad on both sides of the board). These side to side connections are difficult enough in the home environment to make extra effort to minimize them in your layout.YouTube has a lot of material. It is worth viewing a few hours pitching the various approaches to see what fits you best.Even if you eventually decide not to do any boards at home all of this will give you some insight into what the commercial board houses go through. They do have the advantage of doing it over and over again so they can work out the kinks and stabilize around a process that works.

author: Smokey
author_rank: Super Contributor
timestamp: September 25, 2025, 04:59:48 am
content: By far, the "greatest DIY PCB etching method" is to let JLCPCB do it for you.

author: rteodor
author_rank: Frequent Contributor
timestamp: September 25, 2025, 06:18:55 am
content: For toner transfer some people have used modified paper laminators.There is a good thread right here on EEVBlog. If I recal properly modification involves rising the temperature of the rolls from about 160C to 180C, basically above the point of melting the toner powder which is basically a type of plastic. This sets apart the temperature from the tuning process and leaves in the speed of the rolls, the number of passes and the paper type.As for the nasty chemicals: I did etching with nitric acid in like 7th or 8th grade. Its not the devil. Of course life was slower back then. These days I would not recommend this method to the smartphones users.

author: abeyer
author_rank: Frequent Contributor
timestamp: September 25, 2025, 09:22:16 pm
content: Quote from: rteodor on September 25, 2025, 06:18:55 amnot sure I'd recommend life to some of the smartphones users

author: coppercone2
author_rank: Super Contributor
timestamp: September 25, 2025, 09:40:45 pm
content: Quote from: rteodor on September 25, 2025, 06:18:55 amWhile the fumes are trouble, all those chemical processes are interesting because unless your bubbling them super hard, all the waste is well contained in liquid. Biggest one I noticed is chemical paint stripper... almost 100% of the waste products are contained, and the fumes are non persistent. You don't get dust. And for bright dipping... sure it makes some fumes, but you also don't spray polishing compound and brass dust everywhere. Abrasives are really messy compared to chemical treatments. And the mess is persistent, its easy to get it on your hands later if you miss a spot cleaning.I swept after doing a fair bit of polishing on a buff and there was a mound of black dusty shit. Managing a bit of orange fumes is a better option, if you can.Grinding disks, flap wheels, polishing buffs.. .kind of a false sense of security against 'chemical exposure' IMO. The chemicals are actually cleaner and easier to manage often. So long you stick to a process. I wonder how many of the people that are 'playing it safe' actually vacuum, ventilate, wash all their clothing and take a shower after using a grinder or buffAnd abrasive paint stripping is just lol

author: cunningfellow
author_rank: Regular Contributor
timestamp: September 25, 2025, 10:45:23 pm
content: In terms of quality of etching (uniformity and least undercut) this is the reverse order of quality with common home chemistries.1, HCL+H2O22, Ammonia persulphate (this needs to be HOT not warm to work well at all)3, CuCl (that is maintained at proper pH and density)4, FeClFeCl has the advantage that it will survive in bottle on the (rusty) shelf in the garage for many years without attention. It can have its etching life extended by addition of tiny amounts of citric acid and peroxide.FeCl big drawback is messy. It is probably better in all other respects and is what I would recommend if you have a "dirty area" to work in.WRT disposal of chemicals. CuCl never needs to be disposed EVER (but does need maintenance). FeCl will never need to be disposed of if you are etching one board a year. In my area the local tip has "free chemical drop off days".Depending on where you live you might not be able to even put your first rinse water down the sink. In that case do as I do and leave it in a shallow glass/plastic tray to dry out.You can make "mechanical plated through vias" with "copperset through hole system" if you can find one for sale second hand OR if you speak japanese and can buy one from a company in japan that still make a nice kit of a similar bits.Electroplating of vias/through holes is the least fun part to do. If you only need to make one board every two years in an emergency I would recommend not even trying. Either the process is difficult OR the chemicals have short shelf life. Choose your path adventurer.Not using plated holes is my recommendation. If you have a through hole part you can solder top and bottom, then do that. If you have a through hole part you can't solder both sides - put a via pad next to it so you can connect sides with a wire soldered in.I recommend spray etching, but I am biasedhttps://www.instructables.com/The-Etchinator-low-cost-spray-etcher/Bubble and rocking agitation work fine. As do the other two methods I see people advocating. Sponge-rubbing and zip-lock-squishing (I think Big Clives preffered option)For the etch mask. Photographic will give better results than toner transfer, but for 0.25mm/0.25mm (10/10 thou) toner transfer should be adequate if you can get the right paper/printer/process.Some laser printers work great for toner transfer, some not so good.MOST laser printers do not work well for photographic tools. They leave pinholes. Inkjets usually work better if you use the proper transparencies. Inkjet yellow MAY be your most uv-opaque colour if you have dye inks. Black will work best for pigment inks. Do a test with your printer to work that out.There is a spray can sold called "toner density spray" that does work if you ONLY have a (black) laser printer. A spray bottle with a small percentage of acetone does the same job.Negative photoresist is much tougher/stronger than positive. Positive you can buy presensitized board from more places. My preference is dry film negative resist. You can buy a roll from Dupont for about the same price as the GDP of a small south american country OR a few sheets of it from a random aliexpress seller.Drilling is not fun. There is a whole other post to be made about this.If you are keen and have a CNC to do the drilling - double sided 6/6 but with larger vias than JLC/PCBway is within the realm of what you can do at home. You CAN have a good looking double sided PTH board with soldermask in a matter of hours if you are set up for it.I have the knowledge and equipment already to etch boards at home (even multilayer PTH if I kept the chemicals in stock). Last weekend I had to make an emergency board and I dreaded it and wished I had 7 more days so I could just send it off to JLC/PCBWay.JLC/PCBWay is my preferred method because it does not waste 3 hours of my time setting up and also costs mush less even with DHL shipping added.

author: Psi
author_rank: Super Contributor
timestamp: September 25, 2025, 11:03:30 pm
content: It's not worth it for making a PCB to actually use. It just takes too much time vs giving china $20 + shippingIt might take a week or so to get the boards from china, but it will take you days of full time work to make your own boards to an acceptable level of 'usable' quality and this quality is still shit compared to a proper pcb.So unless you just want to have fun it's not worth it.Perhaps if you needed a PCB in 2-3 days no matter what and it's just not possible to get one in time, then it might make sense but that's like a 1 in a million scenario.The cost in materials to do it yourself is pretty low but you do need to use an etching solution.If I was being forced to do it again I would either1- Using a laser cutter/engraver to burn away a protective PCB coating and then etch that. This also has an advantage that you might be able to use the laser to make holes for VIAs/TH if you can get the laser to drill small enough holes through FR4, not sure. Drilling 200+ holes in a PCB with a drill press is super annoying and you will break drills all the time unless you have a really fancy and sold drill press designed for really small stuff.2- Using a DLP system like a SLA printer to expose a UV sensitive PCB.Both of those solutions above also handle one annoying thing, getting the top and bottom layer aligned when doing a 2 layer PCB.Trying to get the top and bottom layers aligned when doing printer toner transfer method is a nightmare. It's doable but you will have a pile of trash boards before you find a way that works. So I recommend against toner transfer unless only doing 1 layer boards.Another annoying thing with DIY pcbs is vias where you want one side connected to the other, plated-through, actually plating them is pretty much never done for DIY/Home pcbs, you usually just solder a piece of really thin wire through the via to make the join. Yet another annoying step you have to do to every via after drilling them. There's also some inserts you can push through to make the join, basically a tiny rivit, but they are only suitable for larger vias.And of course you don't get any solder mask or silkscreen text unless you really want to do that which most DIYers don't bother with.Since your PCB has exposed copper it will look a bit trash after a few months as the copper tarnishes.I guess you could gold plate it pretty easily if you really wanted too.For etch chemicals I found hydrogen peroxide + hydrochloric acid was the best. but as cunningfellow says they all have advantages.If trying to do really thin traces you may need to use FeCl but I found peroxide worked well enough even for small stuff.Also once you have a nice image of a PCB you want to make you cant just use it 'as is' due to side etching.Thin traces will etch sideways and become thinner than they are supposed to be. So you have to modify your design so that it comes out the way you want after side etching happens. If you're not using any parts with smaller pitch than a SOIC you can usually get away with not doing it.Home PCB making is totally doable and is fun but it's just not worthwhile doing if your goal is to get a PCB for something.If you decide to do it your goal should be learning how to make PCBs.

author: cunningfellow
author_rank: Regular Contributor
timestamp: September 25, 2025, 11:50:21 pm
content: Apparently you no longer need to speak Japanese.https://shop.sunhayato.co.jp/products/bbr-5210https://au.rs-online.com/web/p/notching-punching-tools/6312006

author: Psi
author_rank: Super Contributor
timestamp: September 26, 2025, 12:10:39 am
content: One of the things I learned from PCB making and drilling holes in the center of pads was how to use a dot punch and more importantly how to adjust the punch point after doing it and seeing that it's off-center.You do a low force dot punch in the center of the pad as best you can (it almost never ends up centered in the pad).Then if it's not centered you do it again but holding the dot punch at an angle to move the dent deeper and in a direction that moves it back towards the center of the pad.Works really well when you need to dot punch anything by hand and get it perfectly centered.As long as you start small you can work the dent back towards where you want it.

author: artag
author_rank: Super Contributor
timestamp: September 26, 2025, 12:54:57 am
content: I did persist with CuCl for quite a while and still have a tank . Never got on with FeCl. Slow, messy, lots of waste. H202+HCL was too quick for me but maybe could be tamed.The bad side of the chinese manufacturers is that unlike everything else from china, postage is either expensive or slow.But now they're even cheap for 4-layer and flexi boards, I'm getting better at being patient instead of making my own that were limited to 1 or 2 layers, no vias and hand-drilled. And the developer had always gone off when I came to use it

author: ledtester
author_rank: Super Contributor
timestamp: September 26, 2025, 01:51:59 am
content: Consider getting a fiber laser:Prototype PCBs faster than 3D Prints -- Stephan Haweshttps://youtu.be/wAiGCyZZq6wand:Make and Assemble PCBs on your Workbench -- Stephan Haweshttps://youtu.be/5G7jBCK90O0The laser just ablates the copper away - no chemical etching required.The guy also uses the fiber laser to make stencils cut from card stock.

author: Psi
author_rank: Super Contributor
timestamp: September 26, 2025, 02:43:53 am
content: Quote from: artag on September 26, 2025, 12:54:57 amNot sure what you mean, shipping cost in china are very low compared to everywhere else.It can seem expensive if you're thinking of shipping cost as a percentage of the item cost but that's the wrong way to think of it.Making one of something is always going to be expensive vs making 10 of them.I wouldn't call 1-2 weeks slow to get an item. but maybe that's because i'm from NZ and not in the USA with 1 day amazon service.Normally if I need a PCB I have to order parts anyway and that takes about the same from digikey, so having to wait for PCBs doesnt really change anything, would have to wait anyway.

author: RoGeorge
author_rank: Super Contributor
timestamp: September 26, 2025, 07:05:45 am
content: Last time I did a handmade carved PCB.Did that under microscope, with an Exacto Knife to shape the PCB traces. It was a very small breakout board, sort of an adapter between two connectors of different pitches. Not recommended, it was very time consuming.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 26, 2025, 08:36:31 am
content: It's many years since I did it, but I used to do a huge number of homemade PCBs. It helps a lot if you have the space to leave everything set up permanently. 7Probably the most significant tip - if you're using pre-coated PCBs, use silicate, not hydroxide developer. Indefinite shelf-life of solution, and much wider margin between "develop" and "strip".I never looked beyond FeCl, but that was because I had a bubble etch tank permanently set up. AFAIK all the alternatives have shelf-life issues, FeCl lasts forever until it's used up.The biggest pain was drilling, but that's less of an issue these days with SMD designs.BTW If anyone in the UK wants a free Mega tri-tank/sink PCB processing station, get in touch.

author: hfleming
author_rank: Regular Contributor
timestamp: September 26, 2025, 10:13:13 am
content: I am old…. Laser print (double density on a pack of decades-old transparencies), expose on photo-resist covered PCB’s. Develop with sodium(or potassium)-hydroxide, and then etch in a bath with heater and bubbles (OUSIDE!!!!). (Grew up with Ferric chloride, but seeing as I am not the cleanest worker, everything aeound me gets stained, lately I have been using 7%H202 (that I can still get at a pharmacy, without the police starting to look for me) mixed with HCl (that I can still get at some hardware-stores)… for quick and dirty PCB’s, just throw it on my cheap engraving machine… drilling holes, that is a different matter… If I can get my mind to focus, get the drill-info from the Gerbers into Flatcam, and run my (DIY) engraving machine with the appropriate drill-bits trhough the drill-file… more often than that, my brain is not up to that, so I try to drill manually, and breaking quite a few of drill bits… ouch, those Chinese PCB-plants make things so much easier, but it does take some time…

author: rteodor
author_rank: Frequent Contributor
timestamp: September 26, 2025, 10:36:56 am
content: Quote from: hfleming on September 26, 2025, 10:13:13 amI don't think I heard of this kind of etching mix before. How much of each do you use and at what temperature ? How long does the etching take ? And how much does the mixed stuff lasts if left unused ?

author: RoGeorge
author_rank: Super Contributor
timestamp: September 26, 2025, 10:44:09 am
content: For ferric chloride as etchant, the heated bath is easier. It works even without shaking it, and it works even without heating. A simple tray would do it, much easier than building a bubble tank, just that it will take longer.Even faster and maybe easier, too, is the wiping kitchen sponge method.https://www.instructables.com/Sponge-Ferric-Chloride-Method-Etch-Circuit-Bo/Seen that in two variations.One as a piece of sponge dipped in ferric chloride and manually rub the PCB (handled using rubber gloves, though this method is much cleaner than you would think, cleaner than using a tray or a tank). It's also very economic and much faster, it needs only a drop of etchant and the PCB is etched with only a few wipes, in a minute or so.The other variation is to use a ziplock bag, and to seal the PCB inside the ziplock plastic bag, together with a cap of etchant. With good ziplock bags, this can be done without gloves.

author: hfleming
author_rank: Regular Contributor
timestamp: September 26, 2025, 10:57:20 am
content: Quote from: rteodor on September 26, 2025, 10:36:56 amHere is a better link than what I can explain.https://baltic-lab.com/2023/08/etching-pcbs-using-hydrochloric-acid-and-hydrogen-peroxide/And the current mixture what I am using is more than 10 years old…. To re-activate, just add a bit of H2O2 and bubble it for a while…. The finished remains from the previous PCB always goes back into my main bottle…. And I keep on re-using it…. Somewhere on the internet is also a link, that I store locally, telling you what the SG of the solution should be, and I still go according to that formula, adding a bit of HCl before etching to get to that SG… will see if I can find the link…

author: meshtron
author_rank: Regular Contributor
timestamp: September 26, 2025, 09:12:58 pm
content: I've not done this - I just order boards when I need them. But I'd also consider a fiber laser as mentioned above. Also, there are numerous small, desktop-sized CNC mills now that could do the "etching" and the holes in one fixturing. I've got one next to my desk here (haven't played with it yet) that cost me $500 and came with blank PCB boards to play with. Lasers/mills aren't zero mess, but nothing like dealing with toxic chemicals in larger volume either.

author: Psi
author_rank: Super Contributor
timestamp: September 27, 2025, 10:20:46 am
content: Quote from: RoGeorge on September 26, 2025, 10:44:09 amYeah, i always used to heat up a dish of FeCl in a old microwave. Always worked fine.I don't think it was all that good for the microwave, less because of the copper metal in solution and more because the fumes are corrosive and damaged the paint and metal at the top of the microwave over time.If you're wondering, anhydrous FeCl doesnt boil until around 300C but when used for PCB etching it's always mixed with water, so it will boil at 100C and you really don't want that to happen inside a microwave if you value the paint joband it's a real mess to clean up.If you do use an old microwave, do it in small increments until you get an idea how much time is safe. And use a non-metal dish that wont crack and is easy to load/unload.Dropping a dish of FeCl is to be avoided at all costs.

author: RoGeorge
author_rank: Super Contributor
timestamp: September 27, 2025, 10:31:45 am
content: Interesting way to heat the FeCl3.Just out of curiosity, have you ever tried to leave the PCB in it, while heating at a lower power, so to etch under microwaves?

author: Psi
author_rank: Super Contributor
timestamp: September 27, 2025, 10:38:27 am
content: Quote from: RoGeorge on September 27, 2025, 10:31:45 amNa, my microwave was the old type that just pulsed full power on/off. You wouldn't want a copper PCB in a microwave being pulsed to full power.However it might work ok in an inverter based microwave at low power. Could be worth a try. Dunno.I never found keeping the FeCl hot much of an issue, as long as you got the FeCl up to around 60C it worked great.Building a bubbler tank with built-in heater is a way better option and means you're not carrying shallow containers of FeCl around your work area.

author: Labrat127
author_rank: Contributor
timestamp: October 02, 2025, 11:40:36 pm
content: Thank you all for the sharing! It was fun and educational for me to read all the posts. I'm amazed by all the generous details.I have a much better idea how to go about it now. I'll start from a pre-sensitized board. Print my pattern on a laser printer transparency (maybe two to make the dark parts darker). Mount the transparency over the board and expose under UV light. Wash off the exposed film using sodium carbonate. Toss the board in a warm ferric chloride bath for it to be etched (will try the rubbing method, too. Thank you RoGeorge). If I want to go double sided, drill two alignment holes at opposite corners before exposing the second side under UV. Drill 1mm via holes and use a copper wire to connect both sides of the via.Questions:1. What's the typical shelf life of pre-sensitized boards? Six months?2. The pre-sensitized boards I'll end up buying will most probably be positive. Is sodium carbonate a recommended developer for that? Or should I use sodium metasilicate? The former seems to be more available.3. I read somewhere that certain UV exposure units can vacuum and cause the transparency to stick to the board tight. Is that a much desired feature or there're cheaper alternatives? I'm thinking placing a sheet of glass on top to keep the transparency in contact with the board.I understand the benefits of using a Chinese fab house. Just that sometimes you need the board in 2 hours. Cut the board with an X-Acto knife, or etch the board with chemicals. I'd like to be able to do both. Of course, when the components are leaded, I can simply do dead bug style. Thank you all for spending the time sharing your invaluable experience! I love the community.

author: cunningfellow
author_rank: Regular Contributor
timestamp: October 03, 2025, 01:01:21 am
content: 10/10 rules (0.25mm) and you will get away with a sheet of glass and UV lamp. Getting under that and you want vacuum to press the film against the board. Getting even finer (6/6 or lower) you want vacuum and a collimated light source.I really recommend getting a pigment inkjet printer and some multilayer inkjet film. The shite inkjet transperancies they sell at orifice works (staples for USA) are almost as bad as trying to use a laser printer. They are just a film of gelatine on a clear sheet.Ulano/Kiwo and others make/sell the right kind of inkjet film. Google "Inkjet photo positive" and you will find the right kind of film because it is used for screen printing t-shirts. It is slightly milky looking rather than glass clear with a yellow tint from gelatine.If you really have moral/religious objections to having an inkjet printer in your house then get some vellum for the laser printer. It might not look see through to your eyes but it is to UV light and the contrast is higher.Kinsten presensitized positive boards I think have a claimed shelf life of 1 year. I have used old kinsten photopositive stock that is 10 years out of date and it has worked but was not good around the edges.Sodium carbonate vs Sodium metasilicate. Follow manufactures recommendation if they have one. I use sodium metasilicate, but I have seen liquid films that recommend against using it.As I said in post #11 - Positive resist is less durable than negative resist. Sponge rubbing is OK but not the best choice for the delicate positive mask. Sponge rubbing 100% OK for negative resist or toner transfer.

author: coppercone2
author_rank: Super Contributor
timestamp: October 03, 2025, 08:19:48 am
content: I want to find some way of metalizing vias easily. One idea I had, is to make a device that vaporizes a piece of wire that is threaded through the hole. Like with a capacitor. It might make a really good plate job on the hole. The palladium chemistry works well (if you don't get ripped off on oxidized reagents), but I still find it interesting to find other methods, especially for tiny boards.

author: Labrat127
author_rank: Contributor
timestamp: October 03, 2025, 10:19:39 pm
content: I'm also considering mounting dry film on bare copper clad boards. I will get the hot laminator (probably Apache AL13P). But in terms of the dry film, there's these no-brand blue dry films being sold on Amazon. Are they any good? I guess there's no chance for me to get DuPond film given the quantity I'm interested in.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 04, 2025, 06:14:52 am
content: There were also projects to modify a laser printer to print directly on PCB. Black printer toner is made out of microscopic carbon particles covered in plastic. When the page passes through the printer's fuser (oven), the plastic melts and stick to the PCB. Later, that can withstand the etching.Another fun one was to print with water, using a jet printer.You print directly on the PCB, then sprinkle dry toner dust on top, until you cover all the copper clad area. The toner will stick only to the wet areas (sticks to the water traces), and then the excess toner is removed. The remaining toner corresponds to the PCB traces. Then all is baked in a kitchen oven, to melt/fuse the toner on the copper clad surface, then etched.Another DIY one is to make a mini-CNC out of 2 CD/DVD units (to make an XY table controlled by a PC), and to skip all the etching. You simply carve (milling) away only the copper, with the CNC and a high speed drill.All these are fun project, but limited to single sided PCBs, two sided PCBs at most, if you make manual vias. Also, no solder mask, no ENIG, etc. Any PCB house will deliver much better quality, and probably cheaper, too, than the materials+time you'll have to spend making your own PCB.