Robert Baer snipped-for-privacy@localnet.com posted to sci.electronics.design:
That is the number one reason that the transfer method is used with laser printers. remember that the transfer technique flips the image on one axis. See gootee boards.
I'm using this solution. Though it's 1:2 acid:peroxide for me. You don't need water as hydrogen peroxide is 99.5 % water or more. And yes, they are referring to the weak peroxide you can buy in drug stores. Muriatic acid is just weak hydrochloric acid (again, more water than acid).
My typical experience is that a freshly made solution will etch a 10cm by 5cm board in under 5 minutes at room temperature without agitation. Though towards the end of 5 minutes I'd recommend having a look at the board and manually shake your etching tray until done. That's because although this solution is very cheap it is also very strong and can over-etch if you leave your board in for too long.
If you're only making a few PCBs occasionally then the solution will keep for about a week. You can add a bit more peroxide if you find it a bit weak after a couple of days.
If you're making lots of PCBs then you should invest in a bubble tank. Not to speed up etching, this stuff etches in under 5 minutes as is already, but to re-generate the etchant. Once the solution turns blue or bluish green pump bubbles into it until it becomes light green. Then what you have is a completely different etchant -- cupric acid which is a very good industrial grade etchant. Once you've got your cupric acid then you can basically keep regenerating it with air bubbles whenever it weakens.
Toss in a pad or two of steel wool. The copper will plate out onto the steel. When the solution is no longer green, you have clear hydrochloric acid. Neutralize the acid with lye and you basically (no pun intended) have salt water. Steel isn't hazmat. Copper metal isn't hasmat, and salt water isn't hasmat.
By the way, has anybody taken the time to teach you how to snip?
Jim
--
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"Jerry" wrote in message
news:Xns99B56BD3E194Ajerrybcom@199.45.49.11...
Once you\'ve got your
>> cupric acid then you can basically keep regenerating it with air
>> bubbles whenever it weakens.
>>
>
> Thanks for that. How do you dispose of the solution when its used up or
> old?
-- A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing on usenet and in e-mail?
hello, i am using ExpressPCB and i have two layer board.
I need to print one of the images (bottom or top ) flipped and having trouble.
there is a flip option for components so i tried to make my drawing a component but i can not create a component with traces. So what is the method for producing a flipped/mirrored image of the PCB traces ?
so you did JeffryM... so you did. yes i did read it and i know you said it and i do appreciate your sharing your info but jumping through hoops sounds hopeful and.....
i tried kincad and it was just too much there for what i want to do, i mean what do you need to draw a PCB ??? a component list, layer select, trace draw and pad draw thats like 3 buttons and a drop down select box plus an options window for customizing. gEDA was too difficult to install
anyways i was hoping there was a crack.... in my day we used disassemblers, tracers and hex-editors to modify application binaries to enable certain features that were just simply disabled through run time switches or other simplistic internal checks. you could spot these enableable features in apps because the app allowed you perform functions on internal or vendor provided data sets but not on you own data set. Later with windoze "events based" application frameworks and moving config into registry settings there were registry monitoring, file monitoring and events watching tools to watch what the applications were looking for.... occasionally a careless designer/programmer might not hide registry access to a key called flip_option = 0 or you might see an MS_Menu_Item5_Disable event etc....
so if there is no magic user setting then maybe some one has found the simplest loops to jump through and i won't need to rediscover those hoops ??
expressPCB will let you flip their components but not you own custom component then they will not allow traces in custom components nor can user use certain types of pads in the custom components although express does and the output images does not include traces either .....
i see the hoops just wondering how to navigate the hoops, someone made acooment suggesting it was possible so how is the question ?
oh well i guess i could spent that rant learning kincad thanks, robb
I used Express PCB and Schematic to create a one time project. I didn't need Gerber support for further development and the price for boards was OK. I have also used it to produce a board by Toner Transfer. For single sided boards it works fine. The problem is when you need to flip the reverse side copper and the silkscreen. There is no way to print the copper and silkscreen reversed. I made my silkscreen printout by printing to a bitmap, then importing the bitmap into Turbo Cad and flipping it. You can also scan the normal Express PCB output to a JPG format and flip it in a photo editor. You have to be careful with the scaling. I could also replicate the artwork to fill up a whole sheet of patterns. I like the simplicity of the Express tools.
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