2004-09-12 by Thomas P. Gootee
Two slightly-related observations, since this thread's aim seems to be about achieving better/easier release of the paper from the board and toner, after the toner transfer: (PLEASE, also: Read the section farther below, about a special request for everyone's help/participation, which requires a quick test of as many different printers and copiers as possible. i.e. yours too.)
1.) I posted a question, a while back, in a sci.chemistry Usenet newsgroup (http://groups.google.com), asking specifically if anyone there could suggest any sort of substances or procedures that would tend to dissolve paper but not dissolve toner (nor copper). I think that there was only one suggestion that I hadn't already tried that also seemed worth investigating. And that was: Sodium Hydroxide, a.k.a. "Lye", a.k.a. NaOH. I haven't been able to find the time (or the lye) to try it, yet, though. If anyone HAS tried it, or can try it sooner than I can, I would appreciate hearing about it. (Suggestions for common sources of lye would be appreciated, also.)
2.) Regarding there being many variables in "how you work the dough": Absolutely!! EVEN among ONLY the papers that are all labeled, more or less, "glossy inket paper" or "glossy photo paper", just those that are all within 15 feet of each other on the shelves at the local Staples store, here (Jasper, Indiana, USA), the range of "ease-of-release" is almost-astoundingly broad! I tried about 75% of all of the types that were there, a few years ago (spending close to $200 in the process), and found release characteristics ranging all the way from "seems to have *permanently* glued itself to the board and the toner" to "basically slides off BY ITSELF, after five minutes in water, leaving almost NO residue".
I also remember reading an account of the development process leading up to one of the commercial TT papers (maybe the one that's been referred to in this thread), written by one of the people who was involved. My memory of it is a bit sketchy. But I remember that it took them many iterations, to get it to work, at ALL. I seem to also remember seeing the word "sugar", related to the coating that was used. Perhaps they were loosely referring to the Dextrin, that's been discussed in this thread.
BY THE WAY: In the latter example, in paragraph "2.)", above, the paper that "basically slides off the board by itself...", after a short soak, is the "JetPrintPhoto Multi-Project Photo Paper" (made by Hammermill/International Paper, of Memphis, TN, USA, which is available at my local WalMart store, but not at my local Staples store, any more).
I *ALWAYS* use that "JetPrintPhoto" paper for the component-side "silkscreen" artwork TT-application. The only reason I don't use it for the pcb-trace artwork application is that with my HP LaserJet 4 printer, it has "pinholes" in the pattern, and sometimes areas of relatively-poor coverage for certain sizes and/or orientations of lines and larger rectangular areas.
The REASON that I am mentioning it, here, NOW, is that, through correspndence with QUITE a few people who have tried the methods and papers that are suggested on my pcb-making webpage, I have concluded, just recently, that there are large-enough variations among TT results, which seem to be caused by the exact types of printer/copier and toner used, that it seems like it's possible that someone using a different machine and/or toner MIGHT be able to print on that same JetPrintPhoto paper and *NOT* get the pinholes that I get, when using my "HP LJ4/HP toner" combination.
If THAT were to be reported by someone, it could provide an excellent potential solution to the "release" problem, especially if it were a model of printer that is widely available on the used market, for low $.
If you haven't tried that particular paper, you just HAVE to "see it to believe it". It's **AT LEAST** an "order of magnitude" easier (or, actually, probably LITERALLY closer to TWO orders of magnitude easier!) to remove/release from the board, after the transfer, than any other paper I've ever tried! (At the least, knowing that it can be printed with better quality on SOME printer or copier *might* be able to provide some possible clues about alleviating pinhole and image-quality problems, in general.)
Unfortunately, I don't currently have the time or money to buy or borrow, or even find and try, 10 or 20 (or even 5) different used printers and copiers, to test them with the "JetPrintPhoto MultiProject Photo Paper".
Of course, the probablility of finding a machine/toner combination (or even better: a whole class of machines) that would print "perfectly" (or at least "good enough"), with that particular paper, MIGHT be very low. I simply don't know. **BUT**, the benefit of it would be so large, in my opinion, that it seems to justify *some* cost, to try to find out. (Please, see the next paragraph.)
THEREFORE, *** I HEREBY REQUEST *** that everyone who possibly can, PLEASE, try the "JetPrintPHOTO Multi-Project Photo Paper" paper, and then let me know what type of results you get, with the printing step. i.e. how many pinholes you get (or not), overall quality, and the exact make and model of the printer or copier that was used, and the toner if possible, etc. I will then summarize and report the results, here.
*** AND ***: If anyone wants/needs a few **FREE** sheets of that paper, for the purpose of participating in this little testing project, please email your shipping address to me and **** I WILL MAIL SOME TO YOU ****, anywhere in the world, at no cost to you, in exchange for a short email note back to me, describing the quality of the images that you print, with it, and noting the exact make and model of the printer(s) and/or copier(s) that were used, and of the toner if possible.
NOTE: For the printing test(s), please try to print an image that (also) contains some fairly-wide/large areas of solid black (i.e. AT LEAST up to 1/2-inch by 2 to 3 inches in size, or 12 mm by 50 to 75 mm, oriented both parallel and perpendicular to the paper path), and with some range of different line thicknesses, if convenient, etc etc etc. [If necessary, later, too, we could always re-run the test, in a slightly-more-scientific manner, i.e. with a standard pattern that I could email to everyone who participates, and a self-addresed envelope and postage that I could surface-mail to everyone, so they could just mail the actual printouts to me, instead of trying to describe them.] If anyone wants a sample image emailed or mailed to them, for the testing, just let me know.
If participants ALSO want to try actually applying the pattern to a pcb, from the test pattern printed on that paper, that would be good, too, although not required. However, since it's even possible that some combination of all of the steps and equipment involved in the entire process could alleviate the pinhole problem to the point where that paper could be used, it *might* BE well worth also trying to transfer the pattern to a board, just in case YOUR particular method/processing tends to make the problem go away, somehow.
I know this whole thing might sound like a "long shot", to some of you. And if you've never experienced the sheer joy of removing that particular paper from a board after TT, you might be wondering, "Why all the fuss?". But I guess the point is that enlisting the help of as many volunteers as possible will DIVIDE the time and expense, to the point that it becomes practical, and probably worth pursuing. i.e. The cost/risk becomes low-enough, when compared to the probability of success combined with the potential benefit. [Hmmmm.... THAT reminds me of the classic statistical-pattern-recognition (i.e. artificial intelligence) optimization problems that we had in EE608 at Purdue, back in the 1970s, such as: how to implement the "best" recognition and decision algorithms for deciding whether or not a particular re-entry vehicle is a warhead or a decoy. Hehe. Hint: The "cost" of being wrong, in one of the cases, is quite high. Interesting STUFF. Of course, we weren't just *talking* about it, QUALitatively. The "answers"/results were to be QUANtitative, i.e. "discrimination functions" and decision-making equations and such, although we were actually doing more-general studies, of deriving various overall methods for arriving at those equations, and comparing them, etc. But I digress...]
ALTERNATIVELY: If anyone knows of OTHER makes/models of paper (or other printable materials) that are extremely easy to remove after TT, any information about them would be appreciated. That also applies to any "procedures or processes" that might make removal/release become easier or better. (Example: One guy who emailed me swears that putting the boards in the deep freeze for 5 or 10 minutes makes removal much easier. But I haven't been able to get the same magnitude of improvement that he has described. Anyone else experience significant results with that?)
Any other thoughts or ideas about improving removal/release of the paper would also be appreciated.
Thanks!! (And I'm sorry to have "blathered-on", for so long, here, yet-again.)
Regards,
Tom
Tom Gootee
tomg@...
http://www.fullnet.com/u/tomg
P.S.
For your reference:
My "Pcb-Making/Toner Transfer" webpage ("as seen on TV", hehe) is at
http://www.fullnet.com/u/tomg/gooteepc.htm
- Tom
----------------------------
ORIGINAL MESSAGE:
----------------------------
Date: Sun, 12 Sep 2004 05:20:03 -0000Show quoted textHide quoted text
From: "grantfair2001" <grant.fair@...>
Subject: Re: Dextrin as release from TT paper
I think that there are many forms of Dextrin. The Pulsar paper is
"amylose" type Dextrin, but from the 'net it seems that there are
several variables which govern the nature of a specific batch of
Dextrin, such as length of polymer chains, viscosity, etc. As John
Kleinbauer noted it's how you work the dough (for pizza).
Finding the right amylose dextrin/process is probably one part of a
solution.
Paper makers use a machine called a "calender" which has rollers to
smooth the paper. The Pulsar paper looks like the surface had some
texture which has been smoothed out, but only somewhat, like the
"moutain peaks" have been flattened, smoothed, and shiney, while the
valleys retain some roughness and are not as shiny and smooth.
So perhaps paper texture and how to smooth it are also important.
The closest thing to the Pulsar paper in terms of "feel" I have
experienced is brown paper tape. When you get the gum side wet is is
slippery, and if you feel it, a bit "slimey". Seems like that might be
closer to the kind of dextrin required.
Time to go work on a PCB.
Grant
--- In Homebrew_PCBs@yahoogroups.com, "Norman Stewart"
<normstewart@a...> wrote:
> Haven't tried this, but would spraying the paper (any paper) with
laundry
> spray starch give a usable surface? Since the iodine test indicates a
> starch (dextrin?), just might be similar enough. And would prepasted
> wallpaper, which you said has a dextrin content, work - printing on the
> paste side?
> Just a couple of late night thoughts while reading the e-mails.
>
> Norm.
----------------------------
END OF ORIGINAL MESSAGE
--------------------------------------
[Non-text portions of this message have been removed]