How do I (again!)

[trialuser]

Firstly, apologies, it seems the only activity I contribute to on here is to pick you brains.
In my defence, I am about 6 months into this malarky and have no formal training, I get by with the help of youtube, books and 'at the bench'
I've just spent a few days up in Edinburgh and looked around a few galleries and am really taken by the style of Grace Girvan.
I'd really like to try and make something using a technique she uses whereby a shallow oval dish is formed, but it has a wider, flat edge, like this. The thickness of the dish material is about half that of the edge.
I'm assuming I can dome the dish with my round dapping punch into a sandbag, but I can't fathom how to form the edge - it's almost like some 'L' shaped strip around the periphery of the dish
If it is bezel strip it's beyond my capabilities at the moment. Can you but pre formed 'L' shaped bezel?
Thanks.
Martyn

[Dennis]

First of all Martin, Don't apologise. Most of us can't wait for another question-it's what the forum is for.There are many ways these ovals with flat rims could have been made.

The ovals:
On an oval stake, or with an oval doming block and oval punches, or as you say with round punches on something.

The flat rims:
By cutting them out of flat sheet and soldering them on; then adjusting the edges. Alternatively you could make them out of square wire on an oval triblet and then rub them down to be flat and thin

If I were making them, I would make the oval domes in a perspex nonconforming die, reinforced with brass, using my hydraulic press. Then I wold make round wire ovals to match, squash them flat between two metal blocks in the same press, and solder them on.

Now lets see what others would do. Dennis

[trialuser]

Thank you very much Dennis.
I had thought about cutting the rims out of flat sheet - but the ones I looked at seemed so perfect I didn't think they were done like that, I suppose that's the difference between a professional jeweler and a beginner hobbiest!
Would you mind elaborating on what is meant by a nonconforming die. I'm visualising a shallow oval depression carved into a block of perspex, into which is pressed a sheet of silver by a matching convex oval 'presser'.
Just making the tooling seems a lot of work unless you are mass producing? How on earth do you get the bits to match perfectly.
I have a 10 ton pneumatic power press from a previous life, so squashing round section oval shaped rings flat should be do-able.
I had a look at oval doming block / punches - crikey, they ain't cheap.
Cheers
Martyn

[ps_bond]

For the hydraulic side, cut an appropriate hole in a piece of perspex, tape your metal to it (optional, but it does make positioning simpler) and lay it on a block of rubber - urethane is the ideal, but solid neoprene works (actually, so does blu-tak in a pinch). Then squish.

As for the rims on those - I'd probably use a small stake and forge them over.

[Dennis]

Hi Martin,

Here is a non conforming die for a shallow round dome, but not reinforced as you would do for multiple use. I have domed a piece of copper, which was taped on, using the neoprene sheet, between two metal blocks.

Neoprene from the Pentonville Rubber Company comes in several thicknesses and sometimes you need them all, according to depth of die and intricacy of outline.
You can also use urethane sheet, but It flows too well to use like this and really needs to be contained in a metal box.

An old book, Hydraulic Die Forming for Jewellers And Metalsmiths, by Susan Kingsley explains it a bit more. Dennis

[ps_bond]

What durometer of urethane were you using, Dennis? I've not had problems using 95 flowing too much unconfined.

[trialuser]

Thanks again chaps. The picture is very helpful, I didn't appreciate it was 'just' an oval shaped hole rather than an oval shaped carved depression, that makes it within my capability - I think.
I have a hunt around for something firmly squidgy and a couple of blocks of steel .
I looked at the Pentonville site but didn't immediately see anything that looked like urethane or neoprene blocks.
.

[Goldsmith]

Hi Martyn, If you are not planning a production line you can also make any type of domed shape easily with a domed hammer on a block of lead. I make many shapes this way.
A while ago I prepared a short photo tutorial for another forum, it shows how I shaped a copper leaf using a domed hammer and a lead block, you may be interested in seeing it so here is the link; http://www.ganoksin.com/borisat/nena...metal-leaf.htm .

James

[Dennis]

.I looked at the Pentonville site but didn't immediately see anything that looked like urethane or neoprene blocks.
.

I haven't checked recently, but it's neoprene by the metre (you can repair shoes with it). I bought a metre each of three thicknesses about 15 years ago and despite giving some away still have lots left. It cuts easily with a knife or scissors. The company is still there.

When you are ready, if you PM me I could send you enough to start you off. Urethane is very difficult to get in this country, But you might find it interesting to look at it, and the Bonnie Doon Press and accessories at Rio Grande:http://www.riogrande.com/ Dennis.

[Dennis]

What durometer of urethane were you using, Dennis? I've not had problems using 95 flowing too much unconfined.

Hello Peter,

I have been too mean to import it and all my efforts to buy some in UK lead to dead ends. So when two years ago a friend of a friend said she could get me some, I was delighted. I got three blocks, 70x70x10 mm, no durometers given, but they are black(hardest), red(medium) and grey(soft).

In use they squish out sideways, but don't move the metal much. So it's back to neoprene, 6.25, 3.0 and 1.5 mm thick. I often start with the thin for good definition at the margins and progress to a thicker piece next. It's cheap and cheerful and long lasting.

You might remember my heraldic brass buckle which I built up in layers, each formed in this way. I append them here for the interest of Trial User, including the reinforced dies. Dennis.