UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Micro-Porous film for PCB masks

Oldcodger · 30th Aug 2019, 2:35 pm

David on undeveloped ,yes ,using negative resist . It took ages for the resist to dissolve. On the plus side this was using Hobbycraft acetate and the image left was clear with sharp edges.
In my earlier years I used to draw my circuits free hand using either a Dalo or Permanant marker pen. I've tried transfers but left a bit of sweat on the boards and it didn't help etching
I ( as I've mentioned ) use Express PCB ( with my own custom PCB symbols as I feel that the standard ones are ok for firms with expensive kit, but a bit small for us home brew merchants. I've found an easier way of making a negative mask- I use the default colours to design the PCB, then go into options and invert the colours . Problem then is that Express is only designed for a positive mask, so I set the board outer colour to black and copy into a photo program. I use an old MS2000 PHOTODRAW to paste the mask onto the size of film I'll be using ( using the custom paper option) and then the resize option to get the overall board size right. Print onto a bit of plain paper to check some component sizes as a secondary check on the board dimensions and then print the acetate.
All I've go to do now is get the exposure time and develop time right and I'll be there.
I've found that laying down a .1x.1 inch matrix ( as in a bit of vero) with .08 tracks helps me to position components.
Mr B - on the topic of using carbon paper - years ago ( more like two score ) I made the xylophone as in the 70's Practical ?? . The component layout I did freehand, but I used the PCB layout in the mag. Photocopied I stuck this over the board with carbon paper between and used a pencil to mark out the keys.
Swimbo coated this with a coat of clear nail polish and I removed the gaps between keys with a nail. Made a far btter PCB finish than the tracks I'd done with the DALO pen.
Later Swimbo told me she'd seen nail polish pens advertised, but we never found any. She suggested it would be perfect for PCB work.
However I've noticed nail art pens on Amazon at a reasonable price. gel coat- so perhaps we might need Swimbo advice on using these

30th Aug 2019, 2:35 pm	#15
Oldcodger Nonode Join Date: Oct 2014 Location: West Midlands, UK. Posts: 2,181	Re: Micro-Porous film for PCB masks - Homecrafts closing down! David on undeveloped ,yes ,using negative resist . It took ages for the resist to dissolve. On the plus side this was using Hobbycraft acetate and the image left was clear with sharp edges. In my earlier years I used to draw my circuits free hand using either a Dalo or Permanant marker pen. I've tried transfers but left a bit of sweat on the boards and it didn't help etching I ( as I've mentioned ) use Express PCB ( with my own custom PCB symbols as I feel that the standard ones are ok for firms with expensive kit, but a bit small for us home brew merchants. I've found an easier way of making a negative mask- I use the default colours to design the PCB, then go into options and invert the colours . Problem then is that Express is only designed for a positive mask, so I set the board outer colour to black and copy into a photo program. I use an old MS2000 PHOTODRAW to paste the mask onto the size of film I'll be using ( using the custom paper option) and then the resize option to get the overall board size right. Print onto a bit of plain paper to check some component sizes as a secondary check on the board dimensions and then print the acetate. All I've go to do now is get the exposure time and develop time right and I'll be there. I've found that laying down a .1x.1 inch matrix ( as in a bit of vero) with .08 tracks helps me to position components. Mr B - on the topic of using carbon paper - years ago ( more like two score ) I made the xylophone as in the 70's Practical ?? . The component layout I did freehand, but I used the PCB layout in the mag. Photocopied I stuck this over the board with carbon paper between and used a pencil to mark out the keys. Swimbo coated this with a coat of clear nail polish and I removed the gaps between keys with a nail. Made a far btter PCB finish than the tracks I'd done with the DALO pen. Later Swimbo told me she'd seen nail polish pens advertised, but we never found any. She suggested it would be perfect for PCB work. However I've noticed nail art pens on Amazon at a reasonable price. gel coat- so perhaps we might need Swimbo advice on using these