Homebrew PCBs

Ted Bruce KX4OM wrote:
> Jim,
> I found the same problem with residue in the space between the traces
> as you did, using clay-coated inkjet paper and glossy photo inkjet
> paper.  (Good tip on the laundry detergent; I'll have to try that, as
> glossy paper's fast pull-off is easier than rag-content paper's
> rub-off process).  I switched to catalog paper, non-glossy, from the
> Harbor Freight mailed catalog, in fact.  I have to tape it to regular
> printer paper to get it to travel through the machine unwrinkled. 
> Some examples are in the Ted-KX4OM photo folder.  I'm using a
> high-heat Brother HL-2040 (213 degrees C, 415.4 F) that does not do
> well with Press and Peel Blue, so I've done experimentation with
> various other methods.  The last photo, of the simple flash AVR
> programmer, gives a good idea of the resolution achievable.  Check out
> the text on that one.  
>
> I start ironing at about 325 degrees F, with the temperature
> increasing, and iron with moderate pressure for about 2 minutes on an
> EAGLE Cad 3 x 4" board.  I put a paper towel, the blue industrial
> kind, between the iron and the PC board/paper transfer medium.  It
> seems to spread out the heat and offsets the steam holes on the iron
> problem.  By the way, my thermometer is a digital one with an armored
> cable to the probe, which is designed for sticking into meat.  I lay
> the probe tip and shaft under the iron to check the temperature.  I
> bought it for $16 at Harry's Market here in the Atlanta area.
>   
In that the toner I use softens at 230 degrees F , when I need a higher 
resolution, I will get my steel block to 270 degrees F and clamp it over 
the cover paper/image paper/pcb stack to tack the image to the pcb then 
I lay the image paper/pcb (stuck together) on my hot plate and bring the 
temp up to 360 degrees F to melt the toner (without pressure) so it 
sticks well to the pcb ... this I have found reduced the image spread 
... I use a multimeter with a thermocouple input to measure temp ... and 
I use DipTrace to lay out the pcb (DipTrace has a very responsive Yahoo 
group ... you will get an answer to your questions within hours ... it 
also has a very good "Copper Pour" function for building large copper 
areas / ground plains ... and you can do a image flip  and copy and 
paste and pannelize a small pcb to make multi copies on one page ... and 
print ... and a slightly limited version is free ... but the complete 
version is reasonably priced) ...
> The problem I still have is fibers from the paper remaining in the
> space between the tracks.  It amazes me that loose single fibers can
> act as a resist, leaving copper wisps on the board after ferric
> chloride etching.  I usually either scan the board at 600 DPI, or go
> over it with a loupe after etching to check for shorts.
>   
I did an experiment using just plain (no coating) paper ... only 
cellulose fibers for the toner to stick to ... after the bulk paper 
removal, I soaked the transfered image/pcb in the enzyme boosted dish 
washing solution ... a large percentage the cellulose fibers was removed 
but in their place was (lots of) pin holes so I concluded the thick clay 
coated photo paper worked best because the toner was attached to the 
clay and not the cellulose fibers and the enzyme boosted laundry  powder 
solution did a good job of removing the residual clay particles
> I have a better description of the P n P Blue issue and my current
> methods, along with board photos, on my site at www.kx4om.com. 
>
> Good luck with your efforts with with your toner transfer efforts. 
> It's well worth it.
>
> Ted KX4OM 
>   
I like your web site and will visit it from time to time
... thanks for your inputs
Jim KI6MZ
> --- In Homebrew_PCBs@yahoogroups.com, Jim Hutchinson <jhutch17@...> wrote:
>   
> --snip---
> the common thread in the 
>   
>> TT process is difficultly in cleaning the paper residue from the bare 
>> copper after soaking and prior to etching ... the traces I make are 
>> usually 0.015 or larger and spacing is 0.015 or larger and the residue 
>> removal has been the most difficult step ... recently I was talking
>>     
> to a 
>   
>> chemist friend about this problem and he suggested using some enzyme 
>> boosted washing powder (either automatic dishwasher powder or cloths 
>> washing powder) they have enzymes that convert oil to sugar, dirt to 
>> sugar and cellulose to sugar ... the clay coating on the paper I think 
>> is close to dirt and the paper fiber is cellulose ... I used Tide 
>> clothes washing powder (1 tsp to 1 and one half cup of water) at room 
>> temp ... after the initial soaking (in warm water) to remove the bulk 
>> paper and the rubbing of the residue with my thumb to remove as much of 
>> the residue as possible I now soak the PCB in the Tide solution and 
>> after about 5 minutes, almost all the residue in holes and between 
>> traces can be easily scrubbed off with a tooth brush ... an additional 
>> soak may be required for some real stubborn areas ... I now can be 
>> etching 30 minutes after image transfer ... I found the dish washing 
>> powder was too aggressive and would cause small pin holes if the soak 
>> was too long (it works but the timing in more critical ) I would
>>     
> like to 
>   
>> hear from someone that has tried this  ... it really seems to work for 
>> me   .   the toner I use is the toner that comes with my HP1022 laser 
>> printer ... it softens at about 230 degrees F and melts at 310
>>     
> degrees F 
> ---snip---
> 47 
>   
>> lb ... it is coated on both sides (I buy it at Frys Electronics) ... I 
>> have had good results with the TT process on small boards and with the 
>> enzyme soak to remove the residual paper/clay it is also a fast
>>     
> process ...
>   
>> Jim KI6MZ
>>     
> --snip---
>
>
>
>
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