Homebrew PCBs

Alan,

I watched the video, an I am convinced that the Oracal works well with 
heated transfer, where the heat melts the toner and (hopefully) gets it 
to stick to the copper.  I get it. By the same token, the process that 
works so well with heat will not respond well to the cold process.

In the cold process, we get the toner to melt using a solvent. The 
solvent needs to be absorbed into the backing medium to release the 
toner.  The process requirement is the same, we need to melt the toner 
and get it to stick to the board.  With a paper backing, the toner gets 
surrounded by the solvent, and melts. The pressure gets it to stick. The 
backing medium needs to be able to absorb the solvent, and hold it in 
contact with the toner. The Oracal is non absorbent, and therefore much 
less suited to the cold process. The success you've had with it probably 
is because solvent gets trapped between the Oracal and the board. With 
enough pressure you might get transfer, but it is hard to believe that 
you could get uniform distribution of the solvent.

When you heat process the Oracal, you peel the vinyl off the board, and 
leave the toner behind. In the cold process, we soak the paper until it 
almost disintegrates, and then we gently rub the excess paper off.  The 
toner does not really separate from the paper in the same manner as the 
Oracal with heat. There have been many discussions about which kinds of 
paper are best for the process. There is a theory that the shinier paper 
is better than regular printing paper. That seems to be true in my case. 
I use the thinnest, glossiest paper that my printer will handle. The 
gloss must not come from a clay coating. Others have had great success 
with very hard papers like baking parchment. I had no success with that 
paper. The common thread here is that the greatest successes are with 
using paper as the print medium.

Just my $.02

Harvey


On 10/7/2016 1:44 PM, alan00463@... [Homebrew_PCBs] wrote:
>
> MIke N., see this video showing the use of this medium:
>
> Toner transfer video using Oracal 651 vinyl:
> https://www.youtube.com/watch?v=FtmJdCBjwXY
>
> I got the drayer and will have another go at TT with this medium.   
> The Oracal 651 comes stuck to a paper backing.    The paper backing 
> peels off.   The vinyl then has a sticky side which you can attach to 
> piece of paper and feed through the laser printer.       I figured out 
> how to do this using EAGLECAD and made a template so I now know 
> exactly where to attach the sticky vinyl to the paper just before 
> printing it.    If the vinyl gives me any trouble, I'll try printing 
> the artwork onto the glossy paper backing before I consider another 
> medium.
>
> 73,
>
> Alan
>
>