Hi there I read an article as you do, it said to put copper foil on the back and pack enamels into the voids fire then remove, I've just started this method so I'm super new to it

I have been using fine silver

Hi Gil,
I used copper foil myself. It is important to use only transparents which fire clear on copper without Flux underneath.
More recently I use another support material: the thin ceramic material eletronic hybrid circuits are applied to. There is much less grinding to be done to clean the back of the piece. Unfortunately this works only for flat pieces.
Best regards
Gisela

Any idea what that material is called , where do you get it from??

Hi Gil, Sorry , currently I don't know how it's called in English. i'll find out, however it might Take a couple of days. I get my supply from my Brother. Gisela

Aha yes best way to get it for free !! Thanks no rush I have heard of people using titanium ! Might give that a go too

You can remove the copper tinder with diamond pads from the back of a plique a jour. Diamond pad supplier you can find in the Internet. You must work very careful so that the enamel do not break. After this you can fire the workpiece again. You must a support use, therewith the enamel don't touch any basis. Watch the firing. Remove the workpiece immediately when the enamel surface is shiny.

So as Gisela wrote, you can use an other base to hold the enamel in place. I have used glass fibre mats. Such matts you get in shops which sell material for model making like model-ships, model-planes or model-cars. At the first firing of such mat, they develop a bit smoke. You can firing the mats several times. If the workpiece is ready, you can the vast bulk of the glas fibre remove under running water with a tooth-brush. Don't remove the glass fibre in a dry state.The glass fibre disperse itself in your whole workshop!! This  is very unhealthy.
After removing the fibre, the back of the plique a jour is a bit rough. If you wish a smoth back, fire the workpiece as described before. The glass fibre mats are much more better to handle than the classical Mica.

Edmund

Hi Gill, Here is some info my brother provided: the material is Aluminium Oxide Ceramic (Al2 O3, 96%). Or related to the use 'thick film ceramic substrates. A producer in the US is Coors Tek (www.coorstek.com; http://www.coorstek.com/markets/electronicequipment/ceramics/thickfilm.php). The thin tiles are cast, sintered and cut with laser to measure. From this cutting process there will be scrap. And this scrap is the material I use. The cutting is done by Coors Tek but there are also a lot of 'laser cutting houses' working directly for the customers. So the challenge is to find such a laser cutter willing to send you some scrap. It should not cost much. Here is a potentially helpful site:www.ceramtec.de/substrate I hope this helps a little Gisela

thats thats a great tip and a lot of good info thanks for taking the time x

thanks edmund im going to try a few options see what works best many thanks for taking the time to reply in such depth 

Hello Gill,
at the moment I'm digging over my computer a bit. Here I found an older post in which it comes to the production of enamel chips. The enamel powder is sprinkled onto a stainless steel plate and fired. After firing, the enamel layer jumps quite naturally from the stainless steel plate. That could work well with plique a jour. Best is a stainless steel plate with a high nickel content. Maybe that's worth a try.
I think it goes well with titanium.

Left the popped of enamel-chip, right the stainless steel sheet after the enamel pops off.

Edmund

Thanks Edmund I'm going to try all variables and see where they take me, must be more experimental that should be my new year resolution !!

I use fine silver foil for the back.Not the one for enameling just the thick,the book with 25 pages/25 foils of silver 10x10cm cost around 10E.After the bunk is filled enough I use diamond burrs under water to take the foil from the back side and refire the enamel last time.Silver will not discolour the enamel like copper.

M just strong with this technique and was wondering if anyone one has tricks and tips also the firescale from the copper foil how does one remove it from the enamel ??