Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Simao Cardoso 
<simaocardoso@...> wrote:
>
> Hi,
> 
> Although i don't have experience in direct print pcbs i wish to 
share
> some thoughts about it.
> 
> If you print shirts maybe your are using sublimation ink. This ink 
is
> glycerine and Polyethylene Glicol (PEG) with pigments and much 
water. It
> polymerizes with heat and becomes a plastic film.

This is incorrect. 

Sublimation is the process of a solid into a gas, or gas into a 
solid, without a liquid state between.

Sublimation ink works by vaporizing from the paper carrier when 
heated. The gas soaks into a polymer, which becomes porous when 
heated. It then cools and is a permanent part of the polymer.

It only works on polymers. Fabrics must be polyester or contain 
polyester. There are pretreatments for cottons that just spray a 
polymer into the fabric. Plastic items are made of polymers, so as 
long as they can withstand the heat, they can be sublimated to.

But all nonporous surfaces must be coated with a clear or white 
polymer, or nothing will be transfered. Ceramic mugs and tiles, metal 
mugs, all these things must be coated. But the coating itself 
prevents etching, the sublimation does nothing to allow or prevent 
sublimation.

http://www.polyphoto.com/tutorials/bulkinksystem/InkjetFAQ.html

Steve Greenfield