How'd they do that

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KenB259

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I'm sure we've all seen blanks and scratched our heads on how some blanks are made. I have seen these patriotic blanks, like this one and the wavy red and white stripes. Not that I want to make them, but it bugs me that I can't figure out how these blanks are possible, made so perfectly. Does anyone know?
Blank.jpg
 
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jrista

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I suspect...but don't know for sure...that there is a mold they do the initial pour of the blue into. That mold would be round (or round-ish), like the blank (probably larger in diameter), but would have the star shapes protruding inward from its edges. So the blue would harden with the spaces for the white stars. Then the white stars would be filled in.

I picked up a couple of patriotic blanks...oh, I forget who actually manufactures them. I'm pretty sure they were made that way, but they were not then subsequently rounded. They are...octagonal or something in shape, and you can fairly clearly see the layering of the resins. I figure the round blanks like this, are probably rounded after the fact to take off the outer layers of white for the star resin, to show the actual nature of the stars in the blank. In the case for my blanks, I really cannot say what the stars look like (or, for that matter, the stripes in the red blank) because its still just the rough "cut".

It could also be that the blanks are poured round at the desired size, with the star shapes (or line or wavy line shapes, or whatever shape) extruded inward from the inside edge of the mold. Then a hold could be bored through the center of the blank, and then filled from the inside out with the secondary color to fill in the initial voids. In either case, the shapes would be a part of the initial mold, and then would be filled in after the base resin was removed from that first mold.
 

KenB259

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I suspect...but don't know for sure...that there is a mold they do the initial pour of the blue into. That mold would be round (or round-ish), like the blank (probably larger in diameter), but would have the star shapes protruding inward from its edges. So the blue would harden with the spaces for the white stars. Then the white stars would be filled in.

I picked up a couple of patriotic blanks...oh, I forget who actually manufactures them. I'm pretty sure they were made that way, but they were not then subsequently rounded. They are...octagonal or something in shape, and you can fairly clearly see the layering of the resins. I figure the round blanks like this, are probably rounded after the fact to take off the outer layers of white for the star resin, to show the actual nature of the stars in the blank. In the case for my blanks, I really cannot say what the stars look like (or, for that matter, the stripes in the red blank) because its still just the rough "cut".

It could also be that the blanks are poured round at the desired size, with the star shapes (or line or wavy line shapes, or whatever shape) extruded inward from the inside edge of the mold. Then a hold could be bored through the center of the blank, and then filled from the inside out with the secondary color to fill in the initial voids. In either case, the shapes would be a part of the initial mold, and then would be filled in after the base resin was removed from that first mold.
Maybe they have the stars as an extruded shape and somehow place them in the mold and then fill in with blue??
 

howsitwork

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maybe a mould with the extruded stars passing right through it. You then fill the mould with blue resin, pressurise to make sure it fills ( or use really thin resin ) and let it set? That way no matter how deep you cut you still have your stars?
 

KenB259

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maybe a mould with the extruded stars passing right through it. You then fill the mould with blue resin, pressurise to make sure it fills ( or use really thin resin ) and let it set? That way no matter how deep you cut you still have your stars?
Yes, it seems like they must go all the way through.
 

howsitwork

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Going to take a while to set it up but if you’ve got a star extruded or moulded length it’s really only cutting and placing , as you do so eloquently Ken.

Hows pup doing ?
 

KenB259

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Going to take a while to set it up but if you’ve got a star extruded or moulded length it’s really only cutting and placing , as you do so eloquently Ken.

Hows pup doing ?
Nope not planning on making anything like it, just curious on how they do it. Pup is great :)
 

jrista

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Maybe they have the stars as an extruded shape and somehow place them in the mold and then fill in with blue??
they would be a part of the mold itself. They would be extruded from the inside edge of the mold, towards the center.
 

crokett

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I'm guessing 1 of 2 ways. First, the star shapes are extruded and cut into lengths, then they are affixed to a 2 piece mold and the main color is cast around them. The other way there is still a 2 piece mold but the stars are part of the mold. The main piece comes out then is recast with the contrasting star color.
 

KMCloonan

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Fox Lake, Illinois
I'm guessing 1 of 2 ways. First, the star shapes are extruded and cut into lengths, then they are affixed to a 2 piece mold and the main color is cast around them. The other way there is still a 2 piece mold but the stars are part of the mold. The main piece comes out then is recast with the contrasting star color.
I'm gonna say the latter is likely the case. They probably use small core pins to form star shaped cavities on the initial molding, then the core is placed in another mold where the white color of the stars is molded around the core, filling the star cavities. Then the unit is trimmed, removing the white color, except for what is in the star-cavities.
 

jttheclockman

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There are different versions of these out there. These are most likely made in China. The person is a member here or at least has been here selling her wares. If I can find the posts. She is on FB too. There also someone who casts these and I know Ed was selling them as well as these. I bought some years ago. What I found was the inside was cast first with the white and then the blue cast over them They were octagon shaped. Not as small stars and not as sharp. But the blanks were good for larger kits. Somewhere I made one but I can not find a photo.

Here is a past thread from Ed on these. I know it probably the same vendor he got them from and heard stories about that vendor.

https://www.exoticblanks.com/patriot-blank-stars-on-blue.html
 
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