Have you verified that the material is actually Delrin? I’m surprised that settings that work for other folks are bubbling up in your material. You should at least verify that it’s not PVC by subjecting it to the flame test.
This is what I bought:
Amazon.com: BuyPlastic Black Delrin/Acetal Copolymer Plastic Sheet 1/2" x 6" x 24" : Industrial & Scientific
As far as the link you gave me, which one on that list IS delrin?
JSM
They don’t seem to have Delrin (acetal) on that list, but in any case the important thing is to verify that it’s not PVC, which the flame test can help you with. The supplier you linked to seems to get good reviews so it’s probably okay, but you can always verify if you want to be sure.
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My friend who owns a machine shop has delrin and he is going to give me a scrap piece of that to see how that lases in comparison to the stuff I have.
JSM
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Ok, now I have it. Speed 700, power 100, LPI 225. Three identical passes. Yes, the recessed areas are textured, but as pointed out, those might not even show. If they do, there is enough recess for me to lightly coat those areas if I choose. But I think I am going to stamp with this one and see what happens. Check back in a day or two if you’re interested. Got to get me a press. 
I appreciate the help.
JSM
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While presses make everything easier - do know that you can get beautiful stamps with regular clamps 
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Thanks for that. Do you guys wet the leather and then press? Also how long do you press for?
JSM
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Wet and then I left it overnight. The leather was still damp when I pulled them out, but dried the rest of the way after they were out.
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Is there a minimum time or is overnight about the only option?
JSM
Haven’t the foggiest. I did it overnight because that’s the time I was working on it. I’m sure it could be done in less, especially with an actual press, but it was simpler for me to do it last and then deal with it in the morning
If you test and come up with times you should definitely share that with the forum!
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I plan to
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Ok, the first stamp is done. Used a Harbor Freight 6 ton press ($79) and left the stamp for 8 hours. It now has to dry so I’ll take more pictures once that happens. I can see what may be some of the texture from the recessed areas of the stamp, but I can’t say for sure as the sample piece itself had blemishes that looked like scratches in it as well. I think it’s just that. Either way I am happy with the detail.
JSM
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Oh man, that look brilliant! I think the little scratches work with the design, but with just a bit of cleanup to remove the worst background ridges, it looks like you could get a really clean version.
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i guess this is part of why i didn’t have much success, i never left it that long. but my HF press won’t “lock” (unless i can jerry rig something). now i’m going to have to think about how to jerry rig it.
ok, nm. i found where it’s supposed to lock. something to play with this weekend.
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Same with me. Now, I foresee another lesson in patience awaiting me when I try this again.
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i basically see it as a “set it overnight” thing. just clamp it down before going to bed and check it out in the AM.
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Only us pedantic makers would see anything wrong with that.
Have to remind myself every time I’m picking faults at something I’ve made. The general public just goes “oh how freaking cool!”
(Literally had that happen with a piece I’d made for, and gave to, my daughter at a sushi place one evening. Every server and even the chef had to come check it out. Meanwhile I was biting my tongue because of obvious-to-me boo-boos…)
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Of course, you’re right. Easy peasy.
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A couple of other test runs. I’ll say there are still tiny flaws, but nothing I can’t live with. The Rockabilly badge was a tough one to sort out. My intent was to outline the pin up girl but instead engraved the insides of the figure. It looks opposite of the way the rest of the badge looks (like the Rockabilly text and her body are competing) and now the car and the girl look out of place. I’ll adjust on the next attempt.
By the way these are only 6-7 hours 6 ton presses on wet leather. I am considering trying some shorter runs which I can get initial pictures for, but will have to let them sit probably close to a week to see if they look detail over that time. I’ll keep you posted.
JSM
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Wow…I can’t believe how clean and detailed your stamp is. You said you had some flaws, but all I see is a beautiful impression.
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