Hydraulic Die Forming Discussion Group

Stacking urethane

Michael Andrews
michael@thelindsaycollection.com
Wed May 13 '09

After researching the threads, I am unable to find an answer to my question.
I saw on the threads the following information:
4 Basic Rules For Using Urethane for Forming in a Hydraulic Press:
• The harder the urethane, the better the details
• The thinner and softer the metal, the better the details
• The thinner the urethane the better the details
• HOWEVER, never press more deeply than 2/3 of the depth of the urethane. The urethane should be twice as thick as the tool.

I am using 1/4” to 1/2” matrix dies in a 4” round container (like the example in Susan Kingsley’s book, pg. 33 ex.8). If I understand the above information correctly, a 1/4” die would need a 1/2" thick pad. If this is true, would I need to use a single 1/2” pad or could I use four 1/8” pads, or two 1/16” pads plus one 1/8” pad plus one 1/4” pad. Does stacking various pad thicknesses change results in a formed object?
Thanks in advance,
Michael Andrews

Re: Stacking urethane

Phil Poirier
poirier@newmex.com
Thu May 14 '09

Michael,
Also know that soft urethane develops more volume than hard urethane. You'll often use multiple hardnesses of urethane to develop volume then detail.
Stacking urethane is very effective with silhouette dies especially if you lubricate between the sheets of urethane.
I recommend when pressing a tool into soft urethane (like a brake bar or dapping punch) no more than 1/2 it's thickness and when using hard urethane only 1/3 depth. When using a formbox with silhouette dies and soft urethane 1/2 depth is rarely needed.
BTW, you will find that the square formboxes are much easier to use with homemade plexi silhouette dies than the round urethane containers. The round contained urethane is designed for use with bracelet forming dies and mushroom formers, whereas the square formboxes are designed for square plates of die material which is much easier to make and use.
I typically use two 1/2" thick urathanes in my formbox with silhouette dies.
Understand that if you cut urethane with anything other than a shear or scissors you'll be creating a very toxic gas, do not cut urethane with a saw.
I would highly recommend that you attend a workshop with a well qualified instructor such as Cindy Eid or David Reynolds.
Hope this helps,
Phil

On Wed May 13 '09, Michael Andrews wrote
----------------------------------------
>After researching the threads, I am unable to find an answer to my question.
>I saw on the threads the following information:
>4 Basic Rules For Using Urethane for Forming in a Hydraulic Press:
>• The harder the urethane, the better the details
>• The thinner and softer the metal, the better the details
>• The thinner the urethane the better the details
>• HOWEVER, never press more deeply than 2/3 of the depth of the urethane. The urethane should be twice as thick as the tool.

>I am using 1/4” to 1/2” matrix dies in a 4” round container (like the example in Susan Kingsley’s book, pg. 33 ex.8). If I understand the above information correctly, a 1/4” die would need a 1/2" thick pad. If this is true, would I need to use a single 1/2” pad or could I use four 1/8” pads, or two 1/16” pads plus one 1/8” pad plus one 1/4” pad. Does stacking various pad thicknesses change results in a formed object?
>Thanks in advance,
>Michael Andrews
>