Why can't a injet be used for P'N'P' sheets??

[Mike Nichting]

What is the reason that you can't use an inkjet for the press and peel sheets??

mike

[MJ Harnish]

Simply put, it's not the PNP blue that acts as the etch-resistant:  it's the laser printer toner; the PNP just makes it easier to transfer that toner on to your board.  Inkjet inks are water-soluable and so don't offer any protection for the copper against the etchant.  

Incidently, virtually any sort of shiny paper can be used to make transfers to copper-clad boards with a laser printer:  I actually prefer using gloss photo paper run through my laser printer; it's cheaper and actually works better IMO than PNP blue.  I've also used transparencies but still prefer the photo-paper.

[Mike Nichting]

Thank you MJ`!!!!!

Mike

[BillyJ]

Which do you use?
I have tried some fancy HP photo paper and it sucked compared to some way cheaper HP paper that isn't for photos.
The cheaper paper I have had decent results with is 'HP soft gloss laser paper C4179A'
I don't think it is the best out there just the best I have tried so far.

[afranks]

Well, the blue stuff actually is *meant* to be an etch resistant.  The point
with PnP blue is that the toner adheres to the board when you iron it.
Then, when you pull the backing layer away, the blue stuff stays with
the toner, adding an extra layer of resist.

To do an iron-on transfer, all you really need is some clever way to get
the paper to let go of the toner once it's on the board.  PnP blue just
peels off.  Toner Transfer System paper, OTOH, will peel off the board
once you soak it in water. Similarly, most photo papers out there have
a coating which likes to come off when soaked in water.  As long as you
have a laser printer which leaves a nice layer of toner on the paper,
you really don't need the PnP blue.  Photo paper works just as well.
You just have to soak it.  The mid grade, satin gloss stuff seems to
work the best.

BTW, two handy tips. 1) If you use PnP blue, take a piece of packing
tape and pull off the extra blue stuff once you've peeled the backing
layer off of the board.  It makes a huge difference.  2) Always heat
the etchant before you etch a board.  I put my etchant tray in a pan
with hot water in it and let it warm the etchant before I put the board
in.  This helps prevent the etchant from eating under the resist layer
on the edge of traces, which is really important if your board has
thin traces.  The longer it takes to etch a board, the more likely it
is that you'll get traces which are "eroded," for lack of better word.
The warmer the etchant, the less time it takes.

-alan

[Andy]

I used about 6 different types of mylar paper, photo, transparency etc. until I depleted my supply and broke down and bought some blue pnp from smallbear.  I have to say that's the best stuff.  It allows for a more even transfer and the traces are sharper as well.  I noticed that you must "clench" the board to the toner by running cool water over it to make the toner cool off and become solid again.  Ensuring the copper is CLEAN is a must as well.  I found that wiping Tarn-X over it and rinsing it off and MAYBE going over it with some FINE steel wool makes for superb transfers.  Maybe that's overkill but I only did it twice and I really liked that method.

[Rick]

I couldn't agree more, and if you are in a hurry put your Ferric Chloride in a glass bowl and zap it in the microwave for 1 minute. It will munch the copper off like the Tasmanian Devil - maybe less than 7 minutes. It fumes a bit doing this so keep your nose away as much as possible and watch it it's hot.

[Andy]

I was afraid to try that.  Afraid my "other half" would catch me!!!  I saw a neat project that uses a fish tank heater and aerator to speed the etching process.  I will try the microsave trick.

[SoundTech]

I couldn't agree more, and if you are in a hurry put your Ferric Chloride in a glass bowl and zap it in the microwave for 1 minute. It will munch the copper off like the Tasmanian Devil - maybe less than 7 minutes. It fumes a bit doing this so keep your nose away as much as possible and watch it it's hot.

Um, I don't know the exact content of metallic particles in used Ferric Chloride, but it's a bad idea to put anything containing any metal in the microwave.  Also, it's a bad idea to put something toxic in an appliance that you use for food.

[gez]

but it's a bad idea to put anything containing any metal in the microwave.  Also, it's a bad idea to put something toxic in an appliance that you use for food.

Only if it's your own microwave (visit the nice little dear next door and ask very politely to use hers!)

[Paul Perry (Frostwave)]

Others have said this before, but a good 'non-toxic' way to heat etchant is by putting a desklamp with a 200W bulb close up to it. (not a plastic lamp!)

[Rick]

I have an old microwave dedicated to this purpose. If you put lets say an opened can of spaghetti in the microwave it will spark quite a bit. This wouldn't be good for the magnetron tube if done often. (although I did this once at work when I didn't have a bowl - the microwave did survive anyway) on the other hand a tiny bowl filled with FeCl doesn't spark at all, justs gets it hot. If you're paranoid about the miniscule toxic remnents in the oven (just wipe it down a bit after) or use an old beater oven and dedicate it to like purposes. You can burn bacon in the mic and get nitrosamines (cancer causing) as well.
This does work very fast I reitterate.

[SoundTech]

Others have said this before, but a good 'non-toxic' way to heat etchant is by putting a desklamp with a 200W bulb close up to it. (not a plastic lamp!)

I actually set my etchant container on top of my toaster oven, and use that as heat.  Works well.

[Jonas H]

...and if you are in a hurry put your Ferric Chloride in a glass bowl and zap it in the microwave for 1 minute...

Even if the fumes don't hurt you (which I beleive they do) they may hurt the microwave in the long run. The fumes are highly corrosive and I'm sure you will find parts inside the oven that don't take nicely to corrosive fumes. Don't use your expensive oven that is also used to heating food for your children.

[gez]

Don't use your expensive oven that is also used to heating food for your children.

Only if they're your own children (visit the...sorry!)