Etching

[Dennis]

Hopefully Sarah will reply too, but:

Drying of varnish depends on room temperature and how thick the varnish has become after opening, so 2-8 hours. You can apply a sample to scrap and test it with a scriber. It should be crisp.
Maplin and others sell a resist pen for fine work. https://www.google.co.uk/?client=fir...hing&gfe_rd=cr

To get the best out of your solution you agitate and gently brush with a feather from time to time. some use a fish tank aerator.
You remove it when you are satisfied with the depth of etch, or tiny dots are being undermined by etchant. A slower (more dilute) etch is better than a fast one. Dennis.

[enigma]

I used this varnish:
http://www.lawrence.co.uk/shop/Rhind...l#.V8bOSVcbjR0
It dries really quickly once painted on, I can't recall exactly but minutes rather than hours- as Dennis says try a bit on scrap first.
I got the pen but it didn't work for me, I seem to recall that it didn't resist as well, or maybe the nib was too thick, its a while ago so I can't remember exactly why just that I ditched it and went back to the varnish for that job.
I had to apply the varnish for that with a metal scribe as the detail was so fine, very time consuming but most jobs you can do with a brush once you get the hang of it
Make sure you hang pieces upside down in the etching fluid- most items you can just stick strong tape across the reverse side and suspend that way but some you need to be a bit more inventive.
How long you leave them in depends on how deep you want the etch as Dennis says- usually I leave mine for a few hours and check every 1/2hr to an hour.
Be careful not to get the fluid on your fingers or anything else as it does stain.....

[angmc]

Brilliant thanks for all the help and advice guys.

I'm loving this forum already and only been on it a week! Maybe one day I'll have enough experience to impart some advice but for the moment I'm just soaking it all up.

[angmc]

Really sorry I knew there was something else I needed to ask...can you use the same batch of nitrate for silver and copper and can it be stored and used again?

[ps_bond]

No and yes in that order. Not sure what the shelf life of the solution is offhand, but definitely don't etch copper in a solution you've used for silver.

[enigma]

Yes you can use it again but the shelf life isn't great once mixed with water- it seems to weaken fairly quickly.
I just try it in and if its not etching I mix a new batch, its pretty inexpensive on Ebay.

Peter, what happens if you etch copper in a solution thats had silver in, Im curious now?

[ps_bond]

Well, if you wanted to plate the copper rather than etch it... (Note - it won't be pretty and it won't be thick)

I've done something similar by accident - ferric chloride that I'd used on copper I then tried to use to etch steel (forgot it had been used already). The result was pretty, but not what I'd intended.

[enigma]

Thanks Peter! pink steel sounds very pretty LOL

[ps_bond]

It has its uses - a traditional way of marking steel was to use a slightly acidified solution of copper sulphate on it, then scribe through it for layout.