After a month of toner transfers, I've decided to explore UV etching. Toner transfer works really good, but it seems to me UV makes for less cleanup and repair work on the PCBs (those little leftover copper fibers that short out your traces, cleaning up stuck on bits of paper, etc. drives me nuts).
I've noticed photosensitive PCBs aren't that easy to come by anymore. What I do find everywhere is this photoresist film stuff that you apply with a laminator (or an iron if you're brave enough). Sounds ideal in my case where I get my copper clad at the local electronics store (they don't carry UV anymore) and would get the film off Ebay.
Only problem is, since I'm importing the photoresist through the mail, having chemicals in the package is a hit or miss kind of thing. Might go through, or you might get a paper slip saying "yeah... you're not getting that stuff in the little bags".
I've looked everywhere for the formula to this "negative developer" stuff. From what I can see it's sodium carbonate for developing, and sodium hydroxide for stripping the leftover film. Can anyone confirm this, and possibly clue me in on concentrations?
BTW, there's also UV solder mask sheets that I'm looking into. Same thing. Requires developer. Anyone have information on those?
Yes
I use only photo negative pre-sensitized PCB material.
For negative resist only:
sodium carbonate (you can use OXIClean) 1 ounce per gallon of water (good for 9 square feet of PCB)
sodium hydroxide (you can use Draino) 3 ounces per gallon of water (good for 9 square feet of PCB) Store in a GLASS container only!
LarryD:
For negative resist only:
sodium carbonate (you can use OXIClean) 1 ounce per gallon of water (good for 9 square feet of PCB)
sodium hydroxide (you can use Draino) 3 ounces per gallon of water (good for 9 square feet of PCB) Store in a GLASS container only!
Awesome I'll give that a shot. Isn't drain cleaner normally Potassium Hydroxide? That's why I had bypassed it initially.
Shpaget:
Have you tried using vinyl for toner transfer? It leaves no paper residue, hence no copper fibers.
Never tried it. Vinyl like they use for printing street signs? Or is there some kind of laser printer version of the material?
The local copy center has copies on Elite Gloss paper, tried that one once. It came off very well with very little residue, but it gave me the impression that the toner was a little porous. Maybe a temperature thing in the machine for that particular kind of paper.
JohnLincoln:
You can buy photo resist in aerosols, such as this one, to make your own photosensitive PCBs.
JohnLincoln:
You can buy photo resist in aerosols, such as this one, to make your own photosensitive PCBs.
They are generally awful.
Using hydroxide is usless.
Read the link
Xylene appears to have been replaced by somethin else.
Safer maybe , until it proves to have some other effect like turning your hamster into a
Have to use sodium metasilicate as a developer is essential as a very small difference in hydroxide concentration makes a huge difference.
Also the spray is xylene based which is very nasty.
Bur pre coated boards, always gives a better result.
