Ricardos comment seems to have disappeared but it was very informative and may help others so I'm posting it - "For some time now I've been trying to understand too how to produce a nice deep etch that either results in a straight 90º edge or a 45º angled base (as used in plaques/signs or letterpress). I haven't seen any home made process but the professional way uses a machine that mixes a bath of water, nitric acid and etching oil. From what I understand, it's the oil (that I suppose doesn't mix with the rest) that protects the edges while they're bitten away by the acid. I haven't found an explanation on how the etching machine works. I know it spins and I suppose it also emerges and submerges the plate. The trick might be here, as when the plate rises and spins above the bath, it'll throw away the acid and slow down the etching. When it submerges, the oils on the bath surface will adhere to the edges and progressively build up a resist. This would explain somehow the degree edges produced on some etchings but I guess the process is different for the other "just-raised" edge type. Here's an example: sunsetsigns.co.uk/wp-content/gallery/etched-zinc/etching_zinc_6.jpg and this video explains briefly the steps to it: ruclips.net/video/OW-QA7wrPOE/видео.html I have no experience whatsoever with etching or printmaking. I'm just assuming. Nitric acid is a bitch to work with too. "
I've seen folks make photo-etched parts for modelling from thin brass sheet. For simple designs, would it be possible to etch 3-4 or the same thin parts, then stack/glue them on a base plate to give you enough depth? Regarding the undercutting, I wonder if you could carefully add some form of resist to the edges of the etched design mid-way through the etching process. Could that maybe work to hold the undercutting back for just that little bit of additional depth that you need? Just thinking out loud.
seems like there would be too many variables etching the image multiple times and stacking it together, especially if you wanted to do fine details like text etc. I might give it a go though so thanks for suggesting
To HELP with under cutting you need to add resist. Etch it for a while, pull the piece out, add resist to the edge, place it back in the etching solution, repeat. It wont be perfect, but it will reduce under cut. You can try permanent marker etc as resist.
yes I actually tried using the old technique to brush some fine resin (dragons blood or something like that) onto the edges and heat it up so it fuses to the shoulders of the metal etch. It was no way perfect but it did work and prevented undercutting!
Great progress man! I really hope you will find the right method, looks like your almost there! Just some ideas: maybe try copper or magnesium instead of aluminum. Maybe even try other aluminum, to me these plates you used looks quite rough, maybe the the mix of aluminum is just bad and not for this job. Other thing that I remember from PCB making is that I always (for some reason, I read it somewhere) used horizontal position of plate in the acid bath. I we used to stair it, or better say rock the container with the acid that way the plate was always clean in a bath and chemical process was even.
I'm just going to throw this out there. I have seen people use dish soap as a surfactant in water. This keeps the water from beading up. Could you make your initial etch, and then gently add just a thin layer of water to the etched surfaces using a pipette or syringe. Then give the whole thing a light misting of spray paint. Use a vacuum to suck out the dried paint that's sitting on the thin layer of water. I am wondering if this would deposit enough paint on the walls of the etched surface as to prevent the erosion of the walls. Anyway I've been pondering how to get around this problem since I started watching videos like this. Hydrographics made me think about how this might work. I would love to know if you give it a go. It sounds like a simple enough experiment. You just have to hold the spray can at some distance, so as not to disturb the water too much. A couple of very fine layers of paint or maybe primer. Which ever can withstand the etchant.
Ricardos comment seems to have disappeared but it was very informative and may help others so I'm posting it - "For some time now I've been trying to understand too how to produce a nice deep etch that either results in a straight 90º edge or a 45º angled base (as used in plaques/signs or letterpress). I haven't seen any home made process but the professional way uses a machine that mixes a bath of water, nitric acid and etching oil. From what I understand, it's the oil (that I suppose doesn't mix with the rest) that protects the edges while they're bitten away by the acid. I haven't found an explanation on how the etching machine works. I know it spins and I suppose it also emerges and submerges the plate. The trick might be here, as when the plate rises and spins above the bath, it'll throw away the acid and slow down the etching. When it submerges, the oils on the bath surface will adhere to the edges and progressively build up a resist. This would explain somehow the degree edges produced on some etchings but I guess the process is different for the other "just-raised" edge type. Here's an example: sunsetsigns.co.uk/wp-content/gallery/etched-zinc/etching_zinc_6.jpg and this video explains briefly the steps to it: ruclips.net/video/OW-QA7wrPOE/видео.html I have no experience whatsoever with etching or printmaking. I'm just assuming. Nitric acid is a bitch to work with too. "
I've seen folks make photo-etched parts for modelling from thin brass sheet. For simple designs, would it be possible to etch 3-4 or the same thin parts, then stack/glue them on a base plate to give you enough depth? Regarding the undercutting, I wonder if you could carefully add some form of resist to the edges of the etched design mid-way through the etching process. Could that maybe work to hold the undercutting back for just that little bit of additional depth that you need? Just thinking out loud.
seems like there would be too many variables etching the image multiple times and stacking it together, especially if you wanted to do fine details like text etc. I might give it a go though so thanks for suggesting
To HELP with under cutting you need to add resist. Etch it for a while, pull the piece out, add resist to the edge, place it back in the etching solution, repeat. It wont be perfect, but it will reduce under cut. You can try permanent marker etc as resist.
yes I actually tried using the old technique to brush some fine resin (dragons blood or something like that) onto the edges and heat it up so it fuses to the shoulders of the metal etch. It was no way perfect but it did work and prevented undercutting!
Great progress man! I really hope you will find the right method, looks like your almost there! Just some ideas: maybe try copper or magnesium instead of aluminum. Maybe even try other aluminum, to me these plates you used looks quite rough, maybe the the mix of aluminum is just bad and not for this job.
Other thing that I remember from PCB making is that I always (for some reason, I read it somewhere) used horizontal position of plate in the acid bath. I we used to stair it, or better say rock the container with the acid that way the plate was always clean in a bath and chemical process was even.
I know it is pretty off topic but do anybody know of a good website to stream newly released tv shows online?
@Ronnie Castiel i use flixzone. Just search on google for it =)
@Samuel Gunnar yup, I've been using FlixZone for since march myself =)
@Samuel Gunnar Thanks, I went there and it seems like they got a lot of movies there =) I really appreciate it!!
@Ronnie Castiel Glad I could help =)
You should try using the uv dry film photoresist instead and see how you get on
Hi David, the film and emulsion are quite the same so you would still get undercutting
I'm just going to throw this out there. I have seen people use dish soap as a surfactant in water. This keeps the water from beading up. Could you make your initial etch, and then gently add just a thin layer of water to the etched surfaces using a pipette or syringe. Then give the whole thing a light misting of spray paint. Use a vacuum to suck out the dried paint that's sitting on the thin layer of water. I am wondering if this would deposit enough paint on the walls of the etched surface as to prevent the erosion of the walls. Anyway I've been pondering how to get around this problem since I started watching videos like this. Hydrographics made me think about how this might work. I would love to know if you give it a go. It sounds like a simple enough experiment. You just have to hold the spray can at some distance, so as not to disturb the water too much. A couple of very fine layers of paint or maybe primer. Which ever can withstand the etchant.
do you happen to know what acid would go through silver? or is the one in the video sort of "universal" ?
silver nitrate or Ferric Nitrate will work
I somehow read the title "amazing insults at home"