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!
>>
>>
>
>