Adam,
I'm intersted to see your way of applying the resist. :-)
I agree that applying it is something you need to get the hang of it. I
meanwhile simply use a sheet of typewriter paper onto which I put the
PCB. The laminate is then attached to the front of the paper by pressing
a small stripe onto the paper with a finger. I then lift the film with
one hand and feed the paper with the PCB on it into the laminator. Since
I do it this way, I never had any probelms with air bubbles or wrapped
film etc. It should be said that how well this works in general depends
on the kind of laminator too and that's why there does not seem to be
the "only working method" for getting to good results. It's definately
an area where everyone must experiment a little and find the best method
for his own needs. Factors that have influence here IMHO are:
- the diameter of the rolls (IMHO the bigger the better)
- the amount of pressure the rolls apply (usually this can be regulated
with screws in the laminator)
- the temperature
- the amount of time you allow the laminator to have en even temperature
across the rolls. I usually let my laminator run for at least 15 minutes
bevore I start using it.
Again, never heard of applying it "wet". I'm definately interested to
see the pictures. Tanks in advance for takeing the effort.
Markus
Adam Seychell schrieb:
>
> I use dry film resist all the time too. Over the years I've pretty much
> perfected applying the film onto PCB material for prototyping. I used
> "wet lamination" method where the film is applied with a film of water
> covering copper. I have to make a PCB tomorrow so I'll take some photos
> to illustrate. There's a few tricks to it.
>
> The advantage with "wet lamination" is it virtually eliminates dust
> entrapment, wrinkling, and trapped air bubbles. I gave up on hot roll
> lamination years ago.
>
> The only problem is sourcing small quantities of the film. Standard pack
> size is a box of 2 rolls, each 500' long (152 meters) and a choice of
> 12" or 18" wide. In Australia, price was something like AU$600 for the
> 12" rolls. I got lucky and was given some from a PCB manufacture some
> 5~6 years ago. It still works like new.
>
> Adam
>
> water Markus Zingg wrote:
> > I regularly - or better said - almost exclusively work with dryfilm
> > resist. The problem with Positiv 20 you mention is that you will have
> > problems with applying an even layer of it let alone the problems with
> > dust in the air that will stick to it etc.
> >
> > Dryfilm resist is haveing a lot of advantages not only for doing PCBs.
> > As an example, also make aluminium housings for my projects this way or
> > solder stencils. There are both kind of resists available (positive and
> > negative) even though the negative ones dominate. You find positive
> ones
> > i.e. marketed as solder stop mask laminate.
> >
> > I'm also using a regular laminator. You may have to take off the
> housing
> > or modify it in order to adapt it to the thikness of PCB boards. Some
> > are better suited than others, but with the sheer amount of products
> its
> > close to impossible to suggest a given product cause it's likely not to
> > be available where you live anyways. I simply bought one, tried it out
> > and it worked, but that was four years ago. I thus figure that this
> > given product is no longer available. If it would not have worked, I
> > simply would have put it on ebay and tried another one. The price is no
> > real argument nor are the published capabilites cause you will use the
> > laminator out of its official specs anyways hence the needed
> experimenting.
> >
> > HTH
> >
> > Markus
> >
> > dkosokar schrieb:
> >> I'm looking for a positive acting photoresist I can apply at home.
> >> I've wanted to try Positiv 20 but can't seem to buy it in the USA. Can
> >> it be had anywhere that you folks know of? Is it a decent resist?
> >>
> >> What are you folks using? Yes, I know there are presensitized boards,
> >> but they are very expensive.
> >>
> >> Does anyone use dry film resist? I have a laminator, and wouldn't mind
> >> using it if this type of resist works well. Does a regular laminator
> >> work to apply this resist?
> >>
> >> I've tried Datak negative acting resist, without much luck, and now my
> >> bottle is so old, I don't trust it any more. Anyone use this stuff
> >> successfully? I prefer pos resist because it's easier to print than
> >> negatives.
> >>
> >> How about radical ideas like Diazo compounds used for silk screening?
> >> Would this stuff have fine enough detail and woul it stand up to
> >> ferric chloride?
> >>
> >> Any input would be greatly appreciated!
> >>
> >>
> >
> >
>
>