Home PCB etching - one for the hobby-ists

[JohnW2]

I have read that tracing paper rather than transparent sheets for printing the pattern gives good results and resolution with inkjet, but never tried it.

I've done that it my time, with satisfactory results; even ordinary thin paper might work. If one does that, it's obviously essential that one has the printed side in contact with the board. One might expect that, by introducing diffusion of the light very close to the board, tracing paper might tend to increase 'undercutting', but I don't recall that having been a problem.

We are,of course, spolit by technology these days, even though the etching process remains more-or-less as messy (for those of us who don't have fancy machines!). When I first produced etched PCBs, over 30 years ago, I had to create the layout manually on paper using 'Letraset' or similar rub-on transfers, photographically transfer the design onto sheet film, then invert (positive/negative) the image, again using photographic film. For simple 'low-definition' one-off boards, one just used an 'etch resist pen' directly onto bare coppper!

Kind Regards, John

 

[danechip]

I find this process ever so easy. I simply went out and bought an 'Etch a Sketch'

 

[flameport]

Unless this is for single one-off boards, it is not worthwhile doing them yourself any more.
Plenty of companies will produce small quantities of PCBs for very little money.

 

[JohnW2]

Unless this is for single one-off boards, it is not worthwhile doing them yourself any more. Plenty of companies will produce small quantities of PCBs for very little money.

True - but "single one-off boards" are precisely what most 'hobbyists' are usually producing, aren't they?

The moment one wants double-sided boards (unless the second side is extremely simple) and/or plated-through holes, one would certainly be crazy to attempt to DIY it these days.

Kind Regards, John

 

[echoes]

Unless this is for single one-off boards, it is not worthwhile doing them yourself any more.
Plenty of companies will produce small quantities of PCBs for very little money.

Agreed, these are one-off boards for hobby projects. I wouldn't try to manufacture anything other than a prototype.
I don't think I'd be that keen to try a double sided DIY board too often either - the fun stops at mis-aligned pads and I can't be bothered tin plating the tracks, let alone plating vias.

 

[mfarrow]

The first and only double sided board I did was a mini triumpth. OK, the pads weren't completely aligned but it was only half a hole's width out, and I think next time I'll probably not etch the holes on one side, and drill from the other.

That said, for convenience I have had double sided ones made. It's still quite expensive though, £40 I think for a fairly small board, so a significant chunk of a project budget. You only get one shot at getting it right, too! If anyone has had them made cheaper I'd like to know about it.

Ashamably these days, when I had a repeat board to make recently, I reached for the stripboard instead of making one up. I even had the acetate from last time .

 

[DetlefSchmitz]

We just had some experimental boards done in china (ebay). About 50 x 100 mm. 4-layer because of technical necessity. We needed two so ordered 5 for total of £40 including postage. Took 10 days and they sent 10 pieces.

Worked great. We wouldn't do our production boards there, but for prototyping we'd be mad to go anywhere else. This way we get to test out all the critical areas before committing ourselves.

 

[mattylad]

Can you PM me the PCB supplier you used for them?
That sounds better than Eurocircuits and I'd like a few boards making.

When etching at home, a fish tank pump and heater can speed up the etching.
You can even get tinning solution be beware the fumes (toxic), this also needs the heater ISTR.

I used to have to clean out a set of MEGA tanks, they were always a mucky job.

Mind you, it did get rid of a wart once... lol

The board I did today could not be done at home so still use main suppliers.

 

[DetlefSchmitz]

Make me a friend and I will...

 

[echoes]

Just an update on this!

Inket + transparency:

Not bad, but artwork not black enough; resulted in some exposure of the tracks (4 - 5 mins UV exposure time), but got a working board out of it. I'm going to try again but exposing through 2 copies of the artwork. Hopefully that will reduce or eliminate the contrast problem.

Will post results, and pics when I'm happy with the result!

 

[JohnW2]

Inket + transparency: Not bad, but artwork not black enough; resulted in some exposure of the tracks (4 - 5 mins UV exposure time), but got a working board out of it.

Interesting. I take it that you used the 'blackest' possible printing preference setting of the printer? Did you try even shorter exposures?

I confess that I nearly always use a laser printer for this purpose, although I thought I'd sometimes used an inkjet. Maybe laser toner is denser than inkjet ink.

Kind Regards, John

 

[Monkeh]

We just had some experimental boards done in china (ebay). About 50 x 100 mm. 4-layer because of technical necessity. We needed two so ordered 5 for total of £40 including postage. Took 10 days and they sent 10 pieces.

Worked great. We wouldn't do our production boards there, but for prototyping we'd be mad to go anywhere else. This way we get to test out all the critical areas before committing ourselves.

I would very much be interested in knowing your supplier, as that's a very reasonable price for four layer. Although they'd have to be dirt cheap to get me to change supplier for two layer. Feel free to PM me.

 

[ban-all-sheds]

http://groups.yahoo.com/neo/groups/Homebrew_PCBs/info

 

[ban-all-sheds]

I'm resurrecting an old hobby

OOI, why did you not post this in the Hobbies forum?

 

[stillp]

I find this process ever so easy. I simply went out and bought an 'Etch a Sketch'

I once worked for a company that had something very similar to an Etch-a-Sketch, that moved a chisel-pointed scraper across a transparent acetate sheet, removing an opaque coating to produce a negative of the intended pcb. It was very good for simple circuits and narrow tracks, but needed great care to produce tracks at any angle other than 90 degrees.