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trialuser
12-02-2013, 08:42 PM
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 (http://www.gracegirvan.com/ourshop/prod_2245953-Pale-grey-Concave-Stud-Earrings.html). 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
13-02-2013, 12:43 AM
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
13-02-2013, 01:14 AM
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
13-02-2013, 06:58 AM
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
13-02-2013, 03:03 PM
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
13-02-2013, 03:28 PM
What durometer of urethane were you using, Dennis? I've not had problems using 95 flowing too much unconfined.

trialuser
13-02-2013, 08:48 PM
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
13-02-2013, 09:33 PM
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/nenam/how-to-make-metal-leaf.htm .

James

Dennis
13-02-2013, 10:12 PM
.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
13-02-2013, 10:40 PM
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.

trialuser
14-02-2013, 11:46 PM
This ebay seller (http://stores.ebay.co.uk/Silver-Tool-Shop/Hydraulic-Press-accessories-/_i.html?_fsub=5046255015&_sid=48186935&_trksid=p4634.c0.m322) has urethane. Would any of them be suitable?
Seems a tad pricy but that may be the going rate, particularly if it's hard to source.

ps_bond
15-02-2013, 06:50 AM
It is a bit; I've not been able to find sheets reasonably priced in the UK. I've got some of that seller's urethane (65 & 95 duro); it works well, although I wasn't hugely impressed with the combined shipping costs IIRC.

Dennis
15-02-2013, 10:32 AM
At Pentonville Rubber you can get SBR rubber and also neoprene for approximately the same price per metre as one of those littltle squares of urethane.

For occasional use three metres of different thicknesses would last you fifteen to twenty years. Unfortunately you can only order on the phone: 020 7837 7553. Dennis

ps_bond
15-02-2013, 11:20 AM
I've got some 3mm neoprene sheet I can spare a chunk of if needed.

trialuser
15-02-2013, 02:01 PM
Thank you to everyone for the advice and offers.
I have some neoprene on the way now - I might sus out the ebay blocks also.
Oxford is my local town and we have a work standby point literally 100 yards (old units especially for Dennis and Peter :-) )away.
Although looking on google street view I'm not to hopeful about picking up in person.

Exsecratio
01-06-2013, 11:07 PM
Neoprene, Urethane,Hypalon and most of the rest of that family can be gotten from Gill Curry Industrials, (theplasticshop(dot)co(dot)uk

They often have offcuts available for pennies in small sizes of most stuff.

best wishes

Dave

Patstone
02-06-2013, 06:45 AM
James, you make everything you do look so easy. Mere folk like me would struggle to do this sort of thing, I struggled the other day to make an oval that was dished and eventually used a big round doming block, but it didnt look right so I abandoned the idea and did something else. I didnt even realise you could get oval doming blocks.



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/nenam/how-to-make-metal-leaf.htm .

James

Goldsmith
02-06-2013, 07:35 AM
Pat, if you do have a lead block and a hammer with a slightly dome face, you can dome any shape quite easily. I always advise anyone to experiment with sheets of copper scrap to perfect the method of hammering and as I have said before I always make copper patterns to check whether my ideas work, such as in the leaf tutorial. This same method works well for me when shaping flower petals, leaves and even bird's body parts. I wouldn't be without my lead blocks and home made doming and shaping hammers. I buy standard ball pein and cross pein hammers then grind or file them into shape. You can see some of my home shaped standard cheap hammers in this photo, you can buy reasonable hammers suitable for re shaping for under a fiver online.

James

4794

Wallace
02-06-2013, 09:26 AM
Given the recent discussions that included lead as a major toxic player in the game of life, would pewter (lead free) be a suitable replacement? I know it is a little harder, but surely safer to use and to keep around the house, animals, children, etc?

You could melt it easily enough in an old bean tin and pour it into a small aluminium container, I would imagine? I use and old bit of wood with dinks in it, but may try and do a pewter block as I need space.
Just a thought.

Patstone
02-06-2013, 10:37 AM
I thought that lead was only dangerous when it was holding drinking water as in a lead water pipe, not just touching occasionally when doing doming work. Dogs cant reach my bench anyway, and no kids visit, so should be ok. I have probably had more than my fair share of lead anyway as until about 20 years ago have lived in houses older than 300 years so most of the water pipes were lead.
Next question is where can I get a chunk of lead.