Harvey,
You make a lot of sense. The etchant will become "used up" sooner but should
do the job.
I'm playing with etching text into copper. Having a bunch of little dots
would not looks so good.
Never heard of "green foil". A search turned up plenty of foil that is green
but I doubt that is what you are suggesting.
One thing I'm playing with now is the use of 3M Blue painter's tape to hold
on the artwork. It releases a lot easier than 3M frosty Scotch tape.
However, the toner does not fuse into the metal after 10 passes through the
laminator if this blue tape is over the top. This time around I'm only using
on the perimeter. David talked about wrapping the edges of the artwork
around the board. That would avoid the problem of tape over the top of the
artwork.
Another thing I am trying right now is to take the sample out of the
laminator after 5 passes and press it between two blocks of smooth aluminum
with a big chunk of steel on top. I left it there for 1 minute and then put
it in the freezer for 15 (not 30) minutes. The toner did not fuse at all. I
will now repeat the test with 10 passes, press, and freezer for 15 minutes.
Rick
-----Original Message-----
From:
Homebrew_PCBs@yahoogroups.com [mailto:
Homebrew_PCBs@yahoogroups.com]
On Behalf Of Harvey White
Sent: Tuesday, July 30, 2013 10:16 AM
To:
Homebrew_PCBs@yahoogroups.comSubject: Re: [Homebrew_PCBs] Re: Easy Fast Laser Print DIY Circuit Boards -
Dave's toner-transfer freezing technique
On Tue, 30 Jul 2013 09:30:35 -0700, you wrote:
>I'm not "there" yet but am getting close. The silicone based parchment
paper does give up most but not all of its toner after 10 cycles through the
laminator and 30 minutes in the freezer. I think my main problem right now
is toner density. The artwork is not a solid black. So any thin spots in the
artwork appears as thin spots on the copper. However, where there is toner,
it solidly fuses to the copper which is great.
>
>So now I am waiting for the laminator to heat back up so I can run a better
print through it. If this does not work, I will go to a positive artwork
format so only black letters are present on a white background. Less toner
so probably it will be darker. That will mean more copper to etch which
means longer etch time. The longer the time, the higher the probability that
the toner will breakdown.
I think that the "more copper" argument has little effect on the total
etching time. If you have enough etchant flow, I'd simply expect the same
"density" of etchant on each square area of the board, and if it etches, it
won't be at a different rate. In etching different sized boards, I haven't
seen all that much difference in etch times. It's more related to etchant
strength and temperature than otherwise.
The problem with most xerox process copiers is that charge tends to
congregate at the edges of the black area. They've come a long way in
fixing that problem, but it still exists. A large black area of toner will
almost inevitably be thinner at the center.
One way to "fix" the problem is to use a crosshatch fill with very small
dots that still shields (mostly) what you want to shield, but the laser
printer sees as a series of small lines with a lot of edges.
That is also a trick to control board warpage, since (at least they used to)
warp with large areas of copper. That may be a definite case with older
paper based single sided boards.
You may also want to consider green foil or the like to "seal" the top of
the toner, which may help a lot in making the board a bit more rugged as
well as eliminating some of the holes.
Harvey
>
>Bottom line: David's process is showing a lot of promise even though I am
taking liberties with the paper.
>
>Rick
>
>-----Original Message-----
>From: Homebrew_PCBs@yahoogroups.com
>[mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of Rick Sparber
>Sent: Tuesday, July 30, 2013 7:58 AM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: RE: [Homebrew_PCBs] Re: Easy Fast Laser Print DIY Circuit
>Boards - Dave's toner-transfer freezing technique
>
>The test has begun. I printed out some artwork using Microsoft Word and my
HP laser printer. I'm using silicone based parchment paper. The artwork is
mostly black with white letters so the letters should etch out. I used the
"WordArt" feature inside Word to mirror image the text.
>
>I cut out one of the four test coupons and taped it at the ends on a piece
of thin copper plate. I'm using 3M Matte Finish Magic Tape.
>
>I then ran it through my laminator 10 times. It is now in the freezer with
21 minutes to go.
>
>One mistake I think I made was to not tape it all the way around. Before
placing in the freezer, I saw places on the side where the artwork lifted
up. If this is a show stopper, I will clean off the copper and use another
coupon.
>
>Using the laminator is pure genus!
>
>Rick
>
>-----Original Message-----
>From: Homebrew_PCBs@yahoogroups.com
>[mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of David Pickering
>Sent: Tuesday, July 30, 2013 1:07 AM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: Re: [Homebrew_PCBs] Re: Easy Fast Laser Print DIY Circuit
>Boards - Dave's toner-transfer freezing technique
>
>That's the one Robin
>As I said it does come in rolls and its quite thin so you will need to
>flatten it out, if in no rush just put it between some books for a
>couple of days, if urgent just run it through the laminator a couple of
>times
>
>
>________________________________
> From: Robin Whittle <rw@...>
>To: Homebrew_PCBs@yahoogroups.com
>Sent: Tuesday, 30 July 2013, 8:05
>Subject: Re: [Homebrew_PCBs] Re: Easy Fast Laser Print DIY Circuit
>Boards - Dave's toner-transfer freezing technique
>
>
>
>
>Hi Dave,
>
>Thanks - I ordered this material:
>
>http://www.ebay.com/itm/170900415631
>
>A4 10Pcs Sheets Heat Toner Transfer Paper For DIY PCB Electronic
>Prototype
>
>1,677 sold. It cost AUD$2.21 including shipping from Hong Kong from
>seller http://myworld.ebay.com/shcfstore.
>
>- Robin
>
>On 2013-07-30 4:39 PM, David Pickering wrote:
>
>> The paper and supplier that I have been using is on the page you sent
>> marked dib-bid and the suppliers name is shcfstore.
>
>
>
>
>[Non-text portions of this message have been removed]
>
>
>
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>
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>
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>
>
>
>
>------------------------------------
>
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>
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