This page is for me to drop measurements and dimensions on various PCB layouts, especially for ones I've spent way too long searching to find. Hopefully we won't have to dig as deep to find them after this.
Thank you for liking my #CMOS Homemade Operational Amplifier! This op-amp with discrete MOSFETs was more difficult to adjust to the correct operating point than the configuration with bipolar transistors. But I was able to reproduce the feature of high input impedance.
Just reading this again today - I forgot all about it I guess XD.
Funny, now 3 of my 4 computer systems run linux, I use an android phone, and the only windows computer I have is Win7 bc I hate win10. LONG LIVE LINUX!!!
Copper foil is difficult to obtain, but available. It's usually sold per application rather than as 'copper foil' so you could try Fusing Sheet for glazing. Here its used as a colour....
But for small amounts with adhesive and backing sheet eBay sells Slug Tape, also available at garden centres etc. This is perfect for etching, some of them are as little as 40 microns. Slug Away is a big brand, cheap, avoid... ;-)
Wow! Thank you for the information! Yes, copper foil was very difficult to find, so I ordered some copper tape. The tape I ordered was actually designed for electrical things, I think like fixing cables or something. We will see, should come in the mail in a few days! I will check out your links too, they may prove to be good resources if the tape I ordered doesn't work.
No worries, if it saves you banging your head on the desk ;-)
3M also do one with electrically conductive adhesive. You might want to watch out for this little hiccup if it catches on in the industry - its new and hard to find, but if all EMI shielding goes this way it will be hard to find insulating adhesive.
I dont have to tell you what a conductive substrate will do to an etched circuit, the glue is very chemically resistant and will remain after etching, also very hard to clean off.
On the other hand, 3M also sell the conductive adhesives as a one-shot acrylic and two-part epoxy which might very well replace solder in certain places. Like electrical interfaces to aluminium...
Incidentally, Alu is resistive compared to copper, I would be inclined to avoid it for high frequency or higher power work - electron skinning will be pronounced in those tiny traces ;-)
@Morning.Star Yea, I am thinking about the adhesive.... that is my one concern with the tape.
The conductive adhesive though, you say it may replace solder in some instances? That actually would be good for my project because solder melts at too high of a temp for the PLA plastic. I was going to use an alloy but an adhesive could also be a good solution.
I will almost definately not use aluminum for the reason you mentioned and that, according to my experiment, it is awful for etching.
You might get away with low-temp solder if the PLA has support, it goes soggy when warm I've noticed, but it stays put.
The problem with low temp alloys is they use things like Gallium to bring the melting point down. Eg 50/50 Lead and Gallium melts at around 200C but the Gallium will burn before it hits 660C, Aluminium, if it even alloys with it at all. Aluminium is dead fussy, the only good thing I can say about it is its lightweight. ;-)
Conductive adhesives arent hard to make using graphite mixed with a hard solvent glue, or a water-based one like PVA. They turn out pretty resistive, useless for drawing traces because carbon is a few KOhms an inch at best. You can also file down copper or even silver (silver brazing rods are a good source of cheap silver for this) into a dust and mix that with glue for a better one, down to Ohms per inch. You do need a lot of dust for this, and very little glue. Metal dusts can be had in hobby stores, used for model railways and the like.
I've had well over a decade to do thorough research into materials and procedures to fill my memory with. ;-) As a lone parent and then carer I've been unable to work formal hours and got bored and isolated so I taught myself what I needed to make or repair whatever I pleased. 6 months ago I discovered that was called 'hacking'... ;-)
Interesting, Indium.com do Bismuth based alloys. I have some laying around, both pure crystals and some I recovered from some aluminium scrap I melted down in my forge. When I poured the casting I dumped the rest into grooves in the dirt to make ingots out of it, and the very last bit at the end, just a dribble, was Bismuth. I didnt know it at the time, it was more silvery, stayed liquid longer and then made that distinctive gold-purple oxide layer.
That means that Bismuth alloys with Aluminium somehow; although if they are both liquid Bismuth sinks to the bottom.
I'm pretty sure it was the HDD shells the Bismuth came from, the rest was tinfoil, scrap rod and plate...
Dylan Brophy
Tindie
Yann Guidon / YGDES
pokegensplayer04
I found it in this PDF: 
It's from 
From 
Shane C Mason
Don
Vitalii
Julian R
monte
Gabriel Cséfalvay
2mb.beltran
Jorisclayton
FoxHood
Beau L Robertson
Bharbour
Keith
Tim
Thank you for liking my #CMOS Homemade Operational Amplifier! This op-amp with discrete MOSFETs was more difficult to adjust to the correct operating point than the configuration with bipolar transistors. But I was able to reproduce the feature of high input impedance.