Photo Etch Results

It isn't perfect, but after four actual etches and a few aborted attempts I'm pretty chuffed with this one. The first two also-rans used photocopy transfer methods, the second two used photo-etch spray from Maplins, meant for making PCBs. Developed in dilute NaOH and then etched in Ferric Chloride for three hours. It has had two layers of gloss black enamel and needs one or two more, then a damn good polish.

Neil

This was what I used as a starting point - my letters are fatter because of the way I processed the picture.

Edited By Stub Mandrel on 30/04/2012 20:14:33

Edited By David Clark 1 on 04/05/2012 11:42:08

Looks very good to me Neil, nice job on it.

JD

Looks very good.

What did you use for the negative or is it positive? How did you expose it? With a UV lightbox?

Russell.

Hi Russell,

I used the same method I use for PCBs, except I used spray-on etch resist instead of pre-coated board. I use a home-made light box and prepared the positive artwork using a HP laser printer at 1200dpi and scotch 3M film. The artwork was made from the lower image, using corel photo-paint to match the prionter resolution.

Some earlier attempts using the iron-on technique were less good, as was one almost right photo etch where the film was sprayed too thick so a couple of letters etched poorly.

Neil

What material are you etching, Neil. Brass?

BTW, I've tried both the toner transfer and photosensitive methods on PCB's. I've read where some swear by the toner method and describe the photo-method as "difficult to do"

I, on the other hand, have never made the toner-method (in any of its forms) work worth a pinch of coon do-do. Yet to me the photo method is trivially easy ... and pretty tolerant of conditions.

Edited By Sid Herbage on 04/05/2012 01:48:10

Hello Sid Herbage,

What are you using for negatives please.

In Oz ortholith film is difficult to obtain in modest quantities, for use at home

Graham

Very interested in this as would like to learn more, methods, costs , but why is all the text going under adverts and impossable to read!!!

It is not under the adverts on my computer.

regards David

It is not under the adverts on my computer.

regards David

It is on mine David, ie8 on XP sp3 so nothing unusual. I suspect the dodgy software is reserving width for the full size of the first image.

Andy

Hi There

Is that ok?

regards David

Spot on David, Thank you

Andy

Sid,

it's ~0.5mm brass sheet. I have had some success with toner transfer (see the plates in the crane & norden pictures in my albums). I find that it works best if you heat the brass well above iron temperature - heat to where it will singe paper, then allow it to cool a bit and rub the photocopy against it with a bit of wood. But it's dire compared with photo-etching.

I've tried a lot of things over the years - I once made a double sided PCB using a Dalo etch resist pen in an old X-Y plotter.

John,

Ortho film is a bit twentieth century isn't it? These days a laser printer (with quality film) is the best way. I used to use an inkjet with the special film, but you don't get the density and sometimes get streaks.

Neil

Edited By Stub Mandrel on 04/05/2012 19:49:35

Neil, thanks for the material spec. I hadn't appreciated that ferric chloride would work on brass as well as PCB copper. Big light bulb! (and lots of possibilities).

John/Graham, All I've done is to print the pcb artwork (magazine scan or supplied pdf usually) onto overhead projector (transparent) film with a laser printer. (My primary printer has been laser for years - inkjet is just too expensive for regular use). I don't doubt you could use the same technique with inkjet and the appropriate film though.

I sandwich the sensitised board and artwork between a piece of hardboard and a sheet of glass and hang it a few inches below one of the fluorescent fixtures in the shop (I have a wireform shelf permanently hanging there). It's very exposure tolerant - as long as you have the minimum. Developing is straight forward until the excess copper is removed.

For the occasional board rhat I make, I just purchase pre-sensitised boards.

Hello Sid, thank you for your reply.

Neil, I have used ortho film to etch this builders name plate at 7/8" outside diameter and to etch a cliche to pad print the vacuum gauge dial onto a bone china disc at 5/8" outside diameter.

I find my Samsung laser printer is unable to print a 0.002" wide line dense enough to be a satisfactory negative.

Graham

Sorry I seem to be having trouble with pasting the photo.

Graham

Just as an aside, when I use spray on photo resist I use a spinning turntable (made from an old small motor and aluminium plate) and find this gives a very even coating. By altering the spin rate you get different coating thickness, although slower is better for a decent thickness. Bung the treated board into a metal tin to keep the light out and stick it in the oven at lowest setting (about 60-70 degrees C ) for 15 minutes and after cooling the board is ready for use.

Doug

I was jesting John, I'm sure ortho film is still the best possible option for us. Apparently Diane Carney uses an intaglio process with 'silly resolution', but I expect she needs spot on results first time every time

Neil