Making PCBs with a pen

[Top Cap]

http://www.cricklewoodelectronics.co...=search&page=1

A bit pricey at £4 but is it the one you want?

[Biggles]

That's an interesting point about polishing the board, K. I had been using an abrasive rubber block to clean the board before I drew the tracks on. Maybe this is too aggressive. I may try a test board using something like metal polish to clean it, to see if this produces better results. Ed, I have toyed with the idea of circuit design and pcb layout software for many years. It may be time to take the plunge and start using what's available. If it's free, all the better. The thing is, most of my projects don't need a board, but I like the idea of being able to make one easily if I need to.

Just tried that link Top Cap and I couldn't see a pen, which presumably is what you meant?
Alan.

[Nickthedentist]

Search for ERP1 on their site. Looks like the real deal!

[Top Cap]

Link works here and takes you to the ERP1 and also to another, possibly a cheaper but inferior brand.

[Nickthedentist]

Link doesn't work here though, Les. But I think you've found what's wanted!

[Top Cap]

Have attached a screen shot in case anyone else is having problems with that link, it stopped working for me after 4 successful attempts.

[Radio Wrangler]

If you use computer software to lay out your board and it has the facility to output Gerber files, there is always the option of sending the board to one of the prototype board manufacturers. But find out first what their costs are for various constructions. They run them through with a lot of different people's designs on one panel where they're all the same construction and their prices fall quite a lot if you don't want fast service. You can get double sided boards with plated-through holes this way, or even multilayer. Silk screened component layout marking is available.

If you design something which turns out to be popular, you can dust off the files and get a load more made.

It's more expensive than pens and etching your own, but the densities you can do and you can handle awkward parts which are only available in tiny packages. These firms are worth bearing in mind for a special job where you want a professional finish.

There are several firms, the one I've used for work is PCBTrain. Boards turned up on time, despite the -train part of their name.

David

[Mike Phelan]

I never had any success with the Dalomark pens but that was a few years ago, so are probably better now.
The ferric chloride tended to eat through the painted lands when the parts you wanted etching were completely devoid of copper.

At one time, I either used plain paxolin sheet and Cir-kit, or iron-on resist marked with lines, corners, valve bases et al.
I got it from a company in Stockport where it was made.

We sneer at Veroboard but it does have its uses if you're not too far up the RF spectrum.

[Biggles]

That looks like the real deal Top Cap. Sorry for the delay, I had to bale out last night and get off to bed for an early start at work this morning. I have some more bits and pieces I need so I may add a dalo pen to the list. I must admit, they used to work in the past, with a little bit of care not to over etch. Radio Wrangler, I had never considered using production companies for boards, assuming they would cost too much. It may be worth inquiring but in reality the "slow" home method works for the one or two boards I need. I have used plain veroboard for RF up to VHF with wire links successfully, but most of my PCBs have been for audio or low frequency RF work. I use SRBP sometimes as it has a certain period look.
Alan.

[jay_oldstuff]

I have used nail varnish for pcb etching for many years, it works fantatically well. My method is to coat the pcb with masking tape draw the tracks on the masking tape then cut them out with a scalple, i then romove the masking tape where you want the copper to remain then paint over with the nail varnish, allow to go off then pull away the remaining masking tape and then etch as normal then use nail varnish remover to get the nail varnish off. the results can look very good.

Jay

[SiriusHardware]

I was at a Newcastle technical college for a couple of years in the nineties and they were then using a PCB design package on Acorn Archimedes(s) to drive a plotter which drew the finished design directly onto copper PCB using etch-resist pens. It was reasonably successful, but where the potter drew over a track several times to fill it in, if the first layer of quick-drying ink had already dried then the second pass by the pen often scraped through it instead of adding another layer.

Experience also taught me to keep the tracks thick and not to try to pass them between IC pins, because tracks which were thin enough to do that usually got eaten away before the main mass of copper had properly etched, and that may well apply to designs drawn by hand with an etch resist pen as well.

My first home made PCBs were indeed made using the famous DALO etch-resist pens - the ink had a certain (almost certainly toxic) pleasant smell which I've never forgotten.

[Biggles]

That's an interesting technique Jay. I might do a bit of experimenting. I've ordered a proper Dalo pen so we'll just have to see how it goes. The thing is, I'm going to have to make some more boards and I don't need any at the moment. Maybe for the electronic ignition project for my bike, but that's well down the list. I too spent a bit of time at Newcastle Tech in the early eighties Sirius. Plenty of happy and sometimes bizarre memories from there!
Alan.

[Wendymott]

Hi Alan. Just been browsing the CPC catalog and find that PCB "one off" art items are still available.. Ref PCB Etch resistant Transfers Cat number PC00022 to, PC00027, And art penPC01467, all relatively low cost.
CPC is open to all, hobbyist and professional.
Regards
Wendy G8BZY

Originally Posted by Wendymott

To be honest I found the only reliable way is to laser print onto clear acetate.. UV expose onto Photoresist material

Well worth the investment in a UV box and developer if you make more than a few PCBs. I have done PCBs with 1/2mm pitch (thats 0.25mm pads) using this method, they are harder to solder than make.

Free PCB software is also available.

[David G4EBT]

I uses a homebrew UV light box with 4 x 8 Watt UV tubes and a built in timer that I made from a magazine article about 30 years ago, but for anyone wishing to use UV techniques without going ot the considerable expense of a light box, these days you can make a far simpler and economical UV exposure unit. At the link below to ‘Joe’s Hobby Electronics' – the website of Joe Farr - is the basis for a simple but effective UV expose unit that does not need mains voltages or UV tubes, and can be built for around £15 if you do some shopping around for the parts. It uses UV LEDs, which used to be expensive, but now are not so. These LEDs are available from several sellers on EBay at a fraction of the cost from the 'big name' electronic component outlets. (The designer paid £9.99 for 100 including P&P for and says that they were perfect).

The parts list to make this useful project is:

1 x Piece of Vero / Strip board. Size depends on the size of your final UV exposure unit really but this design uses 64 holes x 41 tracks.
99 x 5mm UV LEDs (400 to 405 nm, 2000 mcd)
33 x 56 to 68 ohm resistors *see text
1 x 12v DC 1A Power Supply Unit
Some 22swg solid core tinned wire (or equiv. size)

http://www.hobbyelectronics.net/con_...sure-unit.html

Rather than using pre-sensitised boards, I spray my own boards with UV lacquer because that way, if I under or over expose the boards, or if the developer is too strong, all I need to do is wipe the PCB with meths and re-spray it for another attempt. It's not an exact science and over the years, I've found it a bit hit and miss at times, especially with larger more complex boards.

Never had any success with Dalo pens and the like - I either use a UV mask, or for simple one-off boards, rub down transfers from ESR Electronics. (Hopeless trying to use a Dalo pen for IC pads etc).

Hope that's of interest.

[Ed_Dinning]

Hi Alan, UV light box and etch tank over here if you want to borrow

Ed

[Biggles]

Thanks for the help everybody. Next time I'm on with PCBs I might try the UV photo resist method. I must admit my PCB efforts only come into play if I can't get away with Veroboard so they tend to be one-offs or if I see an interesting project with a board design in a magazine, and most projects seem to require a chassis rather than a board at the moment!
Cheers.

[Anthony Thomas]

I used to use an ordinary felt tip marker to draw the circuit out on a clean piece of copper laminate, I then painted over this with a small paintprush and car touch up paint as this was often cellulose and quick drying. Etch and clean off the paint with thinners.

A now silent key (lived in Bergen) used to draw his circuit and then use a dremmel with dentist drillbit ("bur" I think is the term for them) and a clever little home made straight edge to "router away" undesired copper. He made the smallest of circuit boards for surface mounted components, some the size of large postage stamps. His circuit boards were all straight lines and rightangles, very neat too.

I activly dislike using chemicals to etch away copper.

Tony

[jim_jobe]

If you use Dalo or similar, I always found it to be imperative to leave it for sufficient time to dry, i.e overnight. Any attempt to etch too soon inevitably led to failure. I still have some Dalo pens which must be getting on for 15 to 20 years old and they are still useable.
Jim.

[Bazz4CQJ]

Originally Posted by jim_jobe

I still have some Dalo pens which must be getting on for 15 to 20 years old and they are still useable

Yes, the fact that these pens still work after decades in storage shows that the solvent in the ink is not very volatile, and that being the case, they certainly need appreciable drying time in use. Presumably, this could be speeded up with a gently blast from a hair dryer / heat gun.

B