This....Is....SPARTA!! New embossing plates for use in leatherwork.

[Nicolas Silva]

This....Is....SPARTA!!
This is my latest pair of embossing plates of a male and female warrior for use in leatherwork. Just the results are shown since the plates themselves are rather unimpressive looking. These are probably my most favorite ones I've done to date, probably becuase I love all those old Greek movies and shows (the 300, Atlantis, Hercules, etc). Each is 3x6" and took 5 hours each to cut. It's cut into delrin plastic in a negative profile. I go straight for a finishing cut at a 4% stepover which is why it takes so long. But I don't have to do anything else to them when its done. The embossing process itself is done with a 12 ton shop press and a piece of rubber underneath the leather so that it pushes it up into the plate. Cheers!photo.JPGphoto 2.JPGphoto 1.jpg

[Keith Outten]

Nicolas,

Those are really nice. How about sharing a picture of your press and the setup?
.

[Bruce Page]

Beautiful work! I would love to see your process.

[Nicolas Silva]

well not a lot to show. Here is my shop press beside the arbor press. The shop press was from Weaver Leather, although it originally only came with a 3 ton bottle jack which I upgraded to 12. The arbor press is a 1 ton from harbor freight. Pretty much set and squeeze in both cases. The CNC is the 60th anniv. model from rockler.
photo.JPG

[Nicolas Silva]

I'm using Aspire to make my own 3d models or I buy them on eBay and Vectorart3d.
The two limiting factors are height and direction. As for the direction the model must be made into a negative (subtracted from compenent) so that in the end the embossing is raised. The height is the other problem. Anything over 1/8" is useless. There is almost no way to press it hard enough to get the leather to raise over that (in one piece. i'll explain). In traditional leather hand embossing, you can work the leather from the back side to really stretch the leather. But in my case the only thing pressing from the back side is a piece of rubber or thick leather. To really get a high embossing I'd have to create a positive of the model so that it would really press and stretch the leather when brought together with the other piece. But I really don't want to work that hard. So I settle for a max of 1/8" for the height. All this is important because when you flatten an existing model to 1/8" you often lose a lot of detail. Using the embossing feature of Aspire does help in some cases.
After that, like I said, it is just set it in the press and squeeze. The rubber has enough give to push the leather up into the stamp. I wet the surface under the faucet, but only the top. I don't see any need to have it sopping wet since I am not working the leather for a long time. Only about 10 seconds in the press.
Hope that helps. Cheers!

[Bruce Page]

Thanks for the info. I am surprised it only takes 10 seconds in the press.

[John McClanahan]

This is quite interesting. I work in the printing trade, and embossing/debossing dies are used sometimes. I have a DIY CNC router at home and this delrin plastic has got me thinking....


John

[Nicolas Silva]

Well Delrin has a pretty good hardness which is what makes it so machinable. But while it is hard and holds up well in solid pieces, real thin lines don't hold up very well.
So small details under a lot of pressure are always suspect. I find lines of at least 1 point wide is the minimum safe thickness for leather embossing.

But to give you an idea on the hardness, I was cutting a piece on the table saw and it got pinched between the fence and I got a kickback. It bent one of the teeth on the sawblade. and FYI, I always use my saw guard. It took a chunk out of the plastic, but nothing flew out and hit me or anything behind me. All fingers still in tact. Cheers!

[Perry Holbrook]

Nicolas, have you tried using Lexan (polycarbonate) for the die. I emboss copper sheet using a similar process to yours. I use Lexan, urethane rubber to press into, and a much larger press. (120 ton, 2 stage hydraulic pump). The Lexan holds up well for fine details.

Perry

[John McClanahan]

Nicolas, any pictures of your process you could share with us?


John

[Nicolas Silva]

many things will work for this. It only has to be harder than leather. I use Delrin because it has a higher melting temperature which is important when laser engraving.
-nick

[John McClanahan]

Sorry Nick. I ment to direct the question to Perry.

John