Homebrew PCBs

On Sun, 09 May 2004 16:20:28 -0000, mycroft2152 <mycroft2152@...> 
wrote:

> I've been following this thread for a while now and it has intrigued
> me enough to sacrifice a Lexmark Z52 printer to convert it to a
> straight through printer.
>
It's a thermal, i won't recommend it.


> The major issues (IMHO) is in finding a resist that will: 1. flow
> through the printhead, 2. wet out and print well on the copper
> surface, and 3. will not be removed by the etchant.

You can't use acrylic, and most likely you can't use anything else
than water based. You may try alcohol based.

>
> After a visit to my dentist getting my teeth sealed yesterday, I
> started thinking about uv-curable inks. In other words, a 2-step
> process, printing the resist and then curing it.

Yes this is widely used in wide-format printing e.g on plastic.
It would be very good for PCBs.
I could not find a suitable ink. It must be inkjet ink becasue
the ink you get for screenprinting doesn't fit through.

>
> I thought about getting some of the tooth sealer to try, but I
> realised I was missing the obvious. We already have uv curable
> fluids used for pcb making - the photoresists. I had used a couple
> of time years ago and didn't get the results hoped for. I had used
> the spray cans of resist to sensitize the boards.

They are not uv-curable, they are uv sensitive.
they don't solidify when exposed to UV. they are solvent based.

>
> I remember seeing on the web (forgot the link), a range of pcb
> making chemical that were sold in apllicator bottles, like liquid
> shoe polish. Has anyone used these? Any thoughts?

As said, no better than laquer, they are no uv cure, only uv sensitive.

>
> Myc


If you want to try your printer you should start with aluminium foil.
You have disposeable cartridges so no harm done if it doesn't work.

Get some alcohol based marker ink, and try it.
You must clean your cartridge good before trying it.
smell if it is ammonia (water based). try to flush all old ink out with 
water,
maybe add windex (ammonia cleaner). then flush again to get pure water in 
it.
(print a lot of black pages).

when you are confident that it is pure water empty it, and fill with 
alcohol
(methylated spirits or something). let run a bit to fill all the head with
alcohol and get all water replaced.
the fill in permanent marker ink, diluted with alcohol 1:1. You may also 
try
the metalworking blue, if it is alcohol solved.

then try printing. the alcohol will have a lower boiling point, but maybe
it is in the range that works. What may happen is that the heat of the 
head makes
the nk clog, because only the alcohol is vaporized. then you are doomed 
;-) .


Again, i do not think it is possible to use a thermo-jet. do not try 
acrylic floor
polish, i tried it and it doesn't work.

ST