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jeffathompson
04-24-2008, 05:44 PM
Anybody else have a rookie problem like this.

I have learned to etch. I have tried a number of different things and gotton spotty results.

1st I used photo paper, tired several laser printers and copy machines and settled on one that left a nice image and transfered pretty well to 2 oz single sided copper. Now I say pretty well because what I would get was 50% to 75% results. I am using Waynes PDF of the SSR board from the WIKI and since there are 6 boards on one printout I would get 3 or 4 out of the six that had a good enough image to iron onto the board. Ok, photo paper is cheap and I can run all I want through the laser copier at work.

So I got six nice ones on a board and etched. I used the muratic acid and peroxide for etching. Put em in, etched, and out of the six I got 4 that looked pretty good. The other two had some places that the black came off and etched more than I wanted. But I did that several times and came up with some real nice boards. Drilled them and soldered them, tested and they work. A few failures but the price of learning right.

So then I get some Blue Press and Peel. I run it through the laser printer and get a real nice print the first time. All six look great. Iron them onto the board and quench them, peel the blue off and they look great. I think hey, this stuff is a little more money but it works well enought to make it worth while. I go to etch. Same solution. Same method of putting the plastic case with the acid in a sink full of hot water. Etch takes forever. I use a small soft brush to remove the last of the copper towards the end of the etch. Rinse and check the boards. Much of the small traces and pads are gone, but there are still small specks of copper on the board in the etched areas. The board is not completely clean like when I used the paper. The boards are unusable.

Any idea's? I have read and read and can't figure it out. And yes. I used fresh etching solution each time I etched.

dnesci
04-24-2008, 07:12 PM
I have not used the etching solution that you have used. I used the etching solution that you can buy at Radio Shack (code 276-1576
, in stores only). I used the press and peel and the tec 200 film. Both have worked good. I have gotten a usable board each time.

It sounds as if, you are not getting enough toner on the copper. Make sure the laser printer is set to best print. Normal print may be a little light. Also, the copper has to be prepared propertly to get the toner to transfer well. Wash the boards with an abrasive (like Commet or Ajax) and use a steal wool pad (number 000 or 0000) with the abrasive. Wash the boards until the rinse water will not puddle. The boards should rinse clean. Dry the copper with a lintless rag or paper towel. DO NOT touch the copper side with your fingers. Oils from your fingers is you worst enemy. The toner will sit on the oils and not hold when etched.

When you have small traces, you have to watch the etching carefully, it is easy to over etch.

Good Luck. It just takes a little practice.

Don

kx5h
04-24-2008, 07:18 PM
Hello Jeff,
I understand getting a handle on the toner transfer method of board etching can be a tad iffy in the beginning. It took me quite a bit of time to get where I feel comfortable with it. To be honest, I now prefer it over both silkscreen and photoetch methods. I do not consider myself a pro by any means, but I've etched hundreds of boards using many different methods, and since no one else has stepped up to the plate, I may as well try and give you hand.

I have a couple of concerns. First, what type of printer or copier are you using?

The toner in my Brother 2040 printer will not produce acceptable results at all. When I tried using it, I ended up with results that sound similar to what you are describing. Even trying double and triple printing produced virtually no better results. I have ruled out the Brother printer. I had an old Minolta Pageworks Pro 20 that ended up producing excellent results. After talking with several experienced "etchers," and taking into account my own experience, I feel quite safe in suggesting that toner does indeed make a difference. You might want to try some different toner, i.e., printer / copier.

The next thing that comes to mind is the type of "paper" you have used. I tried the "print, press, and peel" once. The results were at best, so so. It really didn't "Wow" me. I went through every type of glossy inkjet paper available at Walmart, Target, Sams, and a whole host of other stores. None really produced what I wanted. You need to understand, it had gotten to the point to where it was a matter of principle – I was gonna do it. After going back and reading all my documentation, I realized I had not tried the suggested "Staples" brand of glossy paper – the reason, we ain't got no Staple in Clarks, LA – heck I ain't even sure we got one in all of north LA. So I went and ordered a 100 count package off the Staples website. On the first try -- 100% satisfaction. As a matter of fact, every attempt there after, with the exception of one (which I might add was due to my own rushing) has been flawless. Others have had satisfactory results with different brands of paper, some folks even use sheets taken from magazines. I haven't tried that yet – so I can't comment there.

For my experience, I've found that the key points are board prep, paper, toner, iron temperature, ironing pressure, temperature of the etchant, and etchant agitation. I've turned out some very small boards with extremely small traces and I've churned out some boards that were almost motherboard in size all using this method. It really does work.

I also have chosen to use the acid/peroxide method, but use a homemade bubble tank with a bubbler and aquarium heater.

Sorry about being so long winded, but I hope it helps a little.

-- Buddy

kx5h
04-24-2008, 07:20 PM
Apologies to dnesci - You beat me to the punch.

Deast
04-24-2008, 07:56 PM
Just a little info on toner. There is positive and negatively charged toner. I have seen the result of someone refilling a toner bottle in a copier with the wrong type... toner everywhere inside the machine. I work for Konica Minolta in the Philly area, and I happen to own an older Minolta QMS 1250W. It makes great transfers when I set the density to maximum. I will have to check and see what type mine uses, and that may be a new rule.

I have been thinking about taking an old fusing unit that I would normally trash, and modify it to transfer to the copper. I was wondering if anyone has done this before?

Wayne J
04-24-2008, 08:21 PM
In my experience, I have found that HP and Dell printers/toner work best. Staples brand paper is a must. I cannot speak on the etachant, as I use Ferric Chloride. As stated above, there is a lot of factors that come into play, and all of them must be done well, to get nice boards. It takes time to 'get it' but once you do, it will be nothing to whip out a pcb when you want.

Brad Riley
04-24-2008, 10:29 PM
Jeff,

I have been etching Pre-sensitized boards for a few years, and in the beginning did not have much success.
I "float" my plastic container with Developer, then Etchant in a sink with hot water. Seems if the chemicals are 120 to 150 degrees or so it works much faster and doesn't remove those pads and small traces. Don't forget to agitate continuously.

Brad

kx5h
04-24-2008, 10:47 PM
Jeff,

I noticed a couple of points of difference between the method I use and the method that Don describes in the board prep. But, before that, I must agree that he is spot on about "oil" being detrimental. I picked up a box of nirtile gloves from Harbor Freight. They are very effective when it comes to keeping hand contaminants off the board and keeping the acid/peroxide of the hands. That's stuff kinda makes your pinkies tingle when it gets on 'em.

I have had mixed results using steel wool – sometimes getting results of discoloration and areas where the toner just will not stick – I can't remember who, but someone suggested it might be the steel wool. After a bit of tinkering around, I started using 1200 grit sandpaper/emerycloth – vigorously going over the entire board, then rotating the board 90 degrees and repeating – followed up by rotating the board one more time at about 45 degrees and then repeating the sanding. Then the board is cleaned with acetone and upon drying I immediately apply the pcb transfer. The micro scratches from the sandpaper seem to really get a grip on the toner. Plus, this method cuts down on the time of board prep.

I've often wondered about using a fusing unit instead of ironing. I think Don should go ahead and give it a try and let us know the results.

I most definitely have to agree with Wayne, once everything finally clicks for you, you should have very few problems with pcbs from then on.

Heat and agitation has made all the difference in the world on my etchings.

Wayne J
04-24-2008, 11:33 PM
For board prep, I use the green scotchbrite pads on my palm sander (Black&Decker Mouse) I clean the board with brake cleaner. As it has been said, do not touch the copper after cleaning. I also use a can of air to blow off any dust/fiber debris (from the paper towel cleaning) from the board and transfer right before application. Keep in mind that irons have hot spots, so make sure you move the iron around on the transfer, making sure the center of the iron gets to the edges of the board.

mrpackethead
04-25-2008, 01:07 AM
I use press'n'peel, with an oki c5400 printer and get Fantastic results. I can reliably etch down to 12mil track. I'm really lucky my printer seems to deliver great results. The one at work, does'nt, and a few of my friends use mine to print as it seems to work very well. The printer certainly seems to be one of the important things.

Heres my recipe, after printing.

Ensure that the copper board is clean. I use some 000 steel wool, and some dish washing liquid. The surface is bright and shiney after a good wash, and its quite stratched up. ( not sure if thats good or bad ). After its cleaned, only touch it by the edges. Also make sure the edges of the board are smooth, a bit of sandpaper goes well.. this makes sure that the iron does'nt catch the edges.

Iron temp is 155C. That is important.. I'm told however you need to match that to the toner that your printer uses.

I then put my board on a piece of wood, and wipe with a slightly wet cloth. Then put the pressn'peel down. The slight amount of water lets it 'stick'.

Then i place the iron directly on top of the board, in a downwards fashion, with moderate presure.. ( dont' rock it back and forward like ironing a shirt ), and hold it there for 30-40 seconds.. The toner will start to transfer.. I then work the entire board for up to 4 minutes.. Once its done, youll note a change in the look of the blue plastic stuff.. I then drop the whole thing rapiddly into cold water..the press'n'peel then 'falls' off.. And 99% of the time its a perfect transfer.

Etching, i use ammomium persulphate.. Its by far the cleanest and resonably quick etch.. use rougly 1g per 1cm2 of board.. I used to get all scientific about the temperture, but now i just use a jug of boiling water.. The concentration of the mix is'nt critical, you just need enough persulphate.. i normally use a pryex dish and just 'stir' the mix up with a plastic spoon. etch time is normally 3-4 mins..

You want to do this somewhere well ventalated, you'll get a bit of an ammonia smell going on..

And that is what works well for me..

Took me a few goes to get it right mind you..





(1) E

Iron temp needs to be 155degC.

NogginBoink
04-27-2008, 11:38 AM
Does anyone have any experience with Samsung printers? The Samsung ML-2510 is on sale at Fry's for $60 after rebate. I was thinking of picking this up for toner transfer etching.

Also, there's a fairly active group on Yahoo Groups that you might want to join, it's called homebrew_pcbs.

-Matt

omzig
04-27-2008, 12:18 PM
Iron temp is 155C. That is important.. I'm told however you need to match that to the toner that your printer uses.How do you verify this? I have been using an inexpensive clothes iron to transfer. My iron is calibrated in fabric types, not degrees. I usually use the "cotton" setting which is almost full scale. It seems to work pretty good.

jeffathompson
04-27-2008, 04:31 PM
Thanks to all who helped with my etching lessons.

I think I got it. First, the paper/toner situation. The Sam's photo paper seems to work alright. I makes a huge difference what printer I use. My Minolta at home. Scratch that one. The big Xerox at the office, so so results but it appears it gets used so much and I have no control over it that it leaves blank streaks and dirt and spotty images. The $300 5 year old Lanier that we use for a sheet fed copy/fax seems to work the best. The photo paper method works good and so does the blue Press and Peel. Both work the best on the Lanier. The press and peel is pretty much 100% on that copier and a medium hot iron etch. The photo paper is about 80%.
The etch problem appears to have been agitation. I'm not sure how you guys use the aquariam bubbler, but when I called my brother with the Chemical Engineering degree he said when you start that thing up, call the Fire Department at the same time. That much air through Muratic Acid is likely to make it so hot to melt everything in sight. So we got a conference call with my Nephew who has the electronics engineering degree and works for Dolby in California. They have a very highly refined technical method they use when they need to etch a board in a hurry for an in lab project. The use the peroxide/muratic acid solution, make sure both parts are above 100 degree's when they mix them. Use a rubbermade box slightly larger than the board. Put enough solution to cover the board by an inch. Snap the cover on tight. And get this, the secret formula. The set a Black and Decker Mouse sander on the cover of the box. (running of course). Out to the garage, mixed chemicals. Put board in Rubber Maid box. Put sander on top. Thirty minutes I have one perfectly etched board.
Sorry so long but agitate, agitate, agitate.

scorpia
04-28-2008, 03:51 AM
makes my method of agitating look a little pedestrian.

what do i do. I put the board into a plastic tupperware type container with high sides (3-4inches). cover the board with about 1-2 cm's of boiling water from the kettle then add in my etchant (not sure off the top of my head what it is but its white power stuff that makes the waer turn blueish).

now heres the hard part. with rubber gloves on i pick up the container and tilt it back and forwards so the etchant is moving back and forward. works ok. but the water is getting cool by the time its finished.

its might be a little rough but it works

Peter

mrpackethead
04-28-2008, 04:07 AM
How do you verify this? I have been using an inexpensive clothes iron to transfer. My iron is calibrated in fabric types, not degrees. I usually use the "cotton" setting which is almost full scale. It seems to work pretty good.

Well, thats a really good question.. THe first iron i had was calibrated in fabric types. Not much good.. So i used a k type thermocouple which plugs into my multimeter.. It worked pretty well. I just held it up to the plate of the iron. its +/- 5 degress really.. they are not 'accurate' these irons...

Then the iron had an accident.. ( it got dropped, bottom smashed! ).. We found a new one which was on sale that is 'digital'.. its got a lcd readout of the temp.. aint that crazy.. Its a sunbeam 'accura digital'.. According to the thermocouple, it seems to be about right, +/-5 degress again..

The important thing is to match the temperture to the temperture of what the fuser in your laser printer is set to, plus a few degrees. too cold is bad, too hot is bad... Some experimenting is important.. Different toner / printers are different temps.

mrpackethead
04-28-2008, 04:16 AM
makes my method of agitating look a little pedestrian.

what do i do. I put the board into a plastic tupperware type container with high sides (3-4inches). cover the board with about 1-2 cm's of boiling water from the kettle then add in my etchant (not sure off the top of my head what it is but its white power stuff that makes the waer turn blueish).

now heres the hard part. with rubber gloves on i pick up the container and tilt it back and forwards so the etchant is moving back and forward. works ok. but the water is getting cool by the time its finished.

its might be a little rough but it works

Peter



Mate i'm with you.. Sounds like your using Ammomium persulphate. ( is it sort of like white sugar? ).. only thing i do different is use a pyrex dish, and a plastic spoon to slosh it all about.. board takes about 5 minutes normally.. I use 1g of persuplhate per 1cm2 of board ( assuming 2oz copper ).. the 'blueish' tinge you are talking about is copper sulphate..
No big mess, nothing particually noxius.. theres a bit of ammonia smell..

that muratic acid stuff is the hard way i reckon, but if you insist doing it the way.

scorpia
04-28-2008, 04:20 AM
Mate i'm with you.. Sounds like your using Ammomium persulphate. ( is it sort of like white sugar? ).. only thing i do different is use a pyrex dish, and a plastic spoon to slosh it all about.. board takes about 5 minutes normally.. I use 1g of persuplhate per 1cm2 of board ( assuming 2oz copper ).. the 'blueish' tinge you are talking about is copper sulphate..
No big mess, nothing particually noxius.. theres a bit of ammonia smell..

that muratic acid stuff is the hard way i reckon, but if you insist doing it the way.

yeah i must say i tried that other acid and its yuck, the brown stain is still in the bottom of the dish i used. the ammomium is nice and clear doesnt seem to sain anything. almost makes me want to just wash it down the sink. although i think it has bleached some spots in some old tee shirts i used while etchings.

Macrosill
04-28-2008, 07:48 AM
Thanks to all who helped with my etching lessons.

I think I got it. First, the paper/toner situation. The Sam's photo paper seems to work alright. I makes a huge difference what printer I use. My Minolta at home. Scratch that one. The big Xerox at the office, so so results but it appears it gets used so much and I have no control over it that it leaves blank streaks and dirt and spotty images. The $300 5 year old Lanier that we use for a sheet fed copy/fax seems to work the best. The photo paper method works good and so does the blue Press and Peel. Both work the best on the Lanier. The press and peel is pretty much 100% on that copier and a medium hot iron etch. The photo paper is about 80%.
The etch problem appears to have been agitation. I'm not sure how you guys use the aquariam bubbler, but when I called my brother with the Chemical Engineering degree he said when you start that thing up, call the Fire Department at the same time. That much air through Muratic Acid is likely to make it so hot to melt everything in sight. So we got a conference call with my Nephew who has the electronics engineering degree and works for Dolby in California. They have a very highly refined technical method they use when they need to etch a board in a hurry for an in lab project. The use the peroxide/muratic acid solution, make sure both parts are above 100 degree's when they mix them. Use a rubbermade box slightly larger than the board. Put enough solution to cover the board by an inch. Snap the cover on tight. And get this, the secret formula. The set a Black and Decker Mouse sander on the cover of the box. (running of course). Out to the garage, mixed chemicals. Put board in Rubber Maid box. Put sander on top. Thirty minutes I have one perfectly etched board.
Sorry so long but agitate, agitate, agitate.


Great Post Jeff. The method you described is almost exactly the same as I do only I did not think of the sander. I will use that next time.

Wayne J
04-28-2008, 05:20 PM
I wonder what results the use of a old utrasonic cleaner would have. Sounds like the sander bit is making the same attemp. I will have to try the sander.