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Discussion Starter · #29 ·
I wonder if I cast it thick enough could I use actual red candy.
probably if you u used a steel frame to strengthen it
I don't know. It's a strong design and I'm thinking of a 1" slab, recast in a GRP/silicone mould. I'd use a traditional candy apple recipe (minus the apple). We have the beginnings of a serious plan to do a silly experiment.
 

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I really like your style ZDP! You have a talent Bud! Excellent work all around. Love the synthetic wood one especially. Flatband
 

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Discussion Starter · #35 ·
Scott (Fork Hunter),

Last night I laid up the camo print for your slingshot in a close equivalent to realtree, as requested in your PM.



The results are very encouraging; it's as good as any I've done before. The polyester resin has solidified thoroughly, there don't appear to be dry spots, voids or bubbles and the press has produced a laminate plate of uniform 1/2" thickness. Moreover, the print came out well without much darkening and without the colours running. The surface texture is lovely too.

I have now trimmed the slab now that it has had 24 hours to fully set. Examination if the cut cross-section looks good. I've just now rescaled the template to your hand size and I'll cut the board them take a piece of scrap the size of one of the forks and use that to determine the laminate's static breaking strain (hopefully more than 30lbs per fork). Only at that point will I truly know whether the process has been successful and I can begin the simple process of actually making your board-cut frame. Don't worry; my back-up plan is just to put a layer on each side of commercially produced micarta, which is what I might do on a production item, but I feel a full lay-up is so much more satisfying.

I'll keep you posted on my progress over the weekend.
 

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ZDP very nice delicious red slingshot you have there. Very skillful. I was wondering those double blue bands, are they by any chance exercise bands. If they are how strong are they. Are they comparable to the hunters bands. what is the draw weight on the blues.
 

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They are precious!


And yes you have total confidence in the materials at the time of throwing? or it only is for slight shots?


Muy Chula la Manzanita! ZDP







Cjepo
 

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Discussion Starter · #39 ·
They are precious!

And yes you have total confidence in the materials at the time of throwing? or it only is for slight shots?

Muy Chula la Manzanita! ZDP




Cjepo
Cjepo, the acrylic really is only for light bands (compared to Hunter Bands, anyway.) The first post showed those light bands punching holes through both sides of a coke can, so they're not really weak at all. Those are exit holes. The front of the can was caved in.



Nevertheless, acrylic (polymethyl methacrylate, Perspex, plexiglass) is no better than wood. It was used in WWII aircraft canopies and still finds use in structural and engineering applications like large aquarium tanks and submersibles. The main problems are that eventually it may snap under sufficient force, and its ability to resist failure can be severely degraded by weathering. Polycarbonate (Lexan, Makrolon) is similar in flexural and tensile strength to acrylic on specification, but when working with it you get the sense that is not as hard and brittle. Acrylic chips out when you drill through it, whereas Lexan does not. When you sand acrylic on a belt sander, it just disappears, whereas polycarbonate leaves big fluffy burs. Acrylic chips also when you cut it, whereas polycarbonate is a dream to cut. I would have said then that polycarbonate is a better choice, though it is expensive, does not come in such a variety of colours and is not as beautiful when polished to a high finish, which is why I picked it for the Candy Apple project.

See this link for reference: http://www.hydrosight.com/technology/polycarbonate_vs_acrylic.php

The carbon fibre was a lot stronger, as was the G-10 FR4 that I used in the Clone Trooper project. It was no surprise that half an inch thickness of G-10 was strong enough; I could use it as a crowbar. Here are the G-10 specs:

http://www.jjorly.com/g10_fr4_technical_specifications_data.htm

The synthetic wood is basically just like wood but without grain. I'd consider it similar to MDF in strength, but with the weathering properties of PVC or Nylon.

In short, yes, these materials aren't bad at all. You still need to understand how things fail and be careful, as you should with any slingshot, especially board cuts.
 

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Scott (Fork Hunter),

Last night I laid up the camo print for your slingshot in a close equivalent to realtree, as requested in your PM.



The results are very encouraging; it's as good as any I've done before. The polyester resin has solidified thoroughly, there don't appear to be dry spots, voids or bubbles and the press has produced a laminate plate of uniform 1/2" thickness. Moreover, the print came out well without much darkening and without the colours running. The surface texture is lovely too.

I have now trimmed the slab now that it has had 24 hours to fully set. Examination if the cut cross-section looks good. I've just now rescaled the template to your hand size and I'll cut the board them take a piece of scrap the size of one of the forks and use that to determine the laminate's static breaking strain (hopefully more than 30lbs per fork). Only at that point will I truly know whether the process has been successful and I can begin the simple process of actually making your board-cut frame. Don't worry; my back-up plan is just to put a layer on each side of commercially produced micarta, which is what I might do on a production item, but I feel a full lay-up is so much more satisfying.

I'll keep you posted on my progress over the weekend.

That looks outstanding !

I can't wait to hear about how it's going as you progress.

Do I understand you right , that you can't get natural forks where you live ?


- Scott ( Fork Hunter )
 
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