# Build Log - Acrylic slingshot rifle >:-)



## jayw81 (Dec 11, 2011)

Hey guys, embarking on a new project.. Estimated time until completion 2-3 months.

I'm going the use a sheet of 28mm acrylic I was given in return for a promise of a slingshot (not this one...)

Here is the concept sketch:









I have cut the rough shape of the two parts and commenced stock removal/shaping on the 4" belt sander. 40 grit really rips into it and does a great job of getting there quick. Have completed about 25% of the shaping process so far. Some pics below:

















Further details to follow









Jay


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## Hrawk (Oct 25, 2010)

And so it begins !!!

If I can make one recommendation, cover the acrylic with masking tape while you work on it, otherwise you tend to scratch the crap out of it.


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## Btoon84 (Nov 22, 2011)

this is gonna be amazing! I CAN"T WAIT


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## Hrawk (Oct 25, 2010)

Btoon84 said:


> this is gonna be amazing! I CAN"T WAIT


Yeah man, this is dripping with pure awesome already!


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## jayw81 (Dec 11, 2011)

Hrawk said:


> And so it begins !!!
> 
> If I can make one recommendation, cover the acrylic with masking tape while you work on it, otherwise you tend to scratch the crap out of it.


Yeh the mask it had already was scratched up from the jigsaw so I took it off for the pics...


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## Danny0663 (Mar 15, 2011)

Crazy build!
Looking forward to it.


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## JLS:Survival (Dec 8, 2011)

WOW, nice


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## cedar hunter (Dec 31, 2011)

Cool can't wait to watch all come together.


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## Jesus Freak (Dec 31, 2011)

Cant wait to see the finish product!


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## Scrambler84 (Dec 8, 2011)

This is going to be cool when you finish it sure wanna see how your trigger mechanism works.. look forward to the progress on this ..


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## XxDollarBillxX (Apr 28, 2011)

and this is what the follow topic button was made for, looks good so far keep the pics coming


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## e~shot (Jun 3, 2010)

That is a cool project, can't wait


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## tokSick (Jan 25, 2012)

That one is gonna be great, hope it will be finished soon.


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## face.xD (Dec 28, 2011)

Good idea!


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## Charles (Aug 26, 2010)

Like the others, I am really looking forward to seeing the finished project!

Cheers ...... Charles


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## f00by (May 18, 2010)

Oooh. Can't wait!

f00bs


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## jayw81 (Dec 11, 2011)

Technical Discussion:

So, here are some more details regarding the plans for this baby...

Weight: Acrylic is pretty heavy, especially in this thickness. I will update with exact weight figures when I measure it but yeah.. It's heavy. Weight reduction will be a focal point and will likely take the form of either hollowed out areas covered with aluminium plate or a skeletonised stock (tubular stock extension with adjustable acrylic butt). The tubular stock would be useful for ammo storage. Also to consider is that the rifle balance must be kept right.. Trial and error will determine the sweet spot for that one. Last consideration for weight is the need for aesthetic appeal, it's gotta look sweet!

Strength: Not having had much experience in working with acrylic I'm gonna go kinda overboard with strengthening the major stress points on the rifle. The weakest point I can see is the barrel section. The plan here is to maintain reasonable thickness of material (in this case 28x28mm) and reinforce the barrel with two lengths of 25x12x3mm aluminium angle. This will be bolted/screwed to the barrel at regular intervals of approx 100mm. All bolt holes and through holes present a concern for strength reduction as well. These will be reinforced by inserting a section of stainless steel tubing and secured with epoxy resin. These will also prevent a large amount of the compressive forces from the bolts being transferred to the acrylic directly. This makes me feel better since I don't know the compression strength of acrylic.

Firing Mech: My plan it to use a slotting drill bit to do some lo-tech milling to create a space for the trigger and release mechanism. More details on this later with accompanying drawings.

Aesthetics: Still not sure what the final design will look like but I will be looking through a bunch of rifle pics and adjusting it to resemble the ones I like best. I expect the acrylic to look quite striking when the piece is complete and plan to contrast the clear plastic with satin finish aluminium and stainless where reinforcement is required.

Size/Dimensions: As previously stated, the main construction material is 28mm acrylic, leading to the thickness of the finished piece naturally being 28mm. The height of the piece is approx 125mm or 5 inches. Finished length anticipated to be 100cm. Finished draw length approx 90cm. Dimensions are not yet set in concrete (except I can't cut stuff bigger) and finished length will depend on the style of stock used.

Ammo Storage: There are two ways I was thinking of storing ammo on the rifle. The first is by inlaying a series of small magnets (20 or so) along the underside of the barrel for storage of steel ammo balls. For lead ball storage I am intending to utilise either a tubular stock or a storage hole drilled into the stock. Again with capacity to store about 20 balls.

Sighting: My plan at this stage is to build a top rail and include a homebrew sighting tube. Can upgrade to dovetail mounted optical sight in the future if warranted.

These are my thoughts so far. Suggestions or improvements welcome.. Can't wait to see it progress









Jay


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## Hrawk (Oct 25, 2010)

I don't think strength will be an issue. I have been using 20mm for years in very high power sub boxes and only experience minimal flex over large sheets. We're talking up to 4000 watts of subs and baffles as large as 1400x600mm.

Do you have access to a router for rounding the edges ? This would probably be the best way to cut your slots if you don't have access to a mill.

Ammo storage is a neat feature. Perhaps a spring loaded magazine tube with a strong magnet catch on the end. This would look awesome inside the clear acrylic.

If you really wanted to add some wow factor, add a battery recess and use a cheap laser module for sighting as well as a few coloured LED's to give the stock a glow effect.

Jaycar sell a small 1mw laser module for about $15. It's fairly easy to make these adjustable to zero them in. Or you could go crazy and add the 10mw green ones they sell, these are considerably more expensive though.

Don't forget the front rail for tactical flash light and bipod attachment


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## jayw81 (Dec 11, 2011)

Ooh I like the bipod idea


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## zhop (Dec 6, 2011)

thats going to be awsome


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## cheese (Nov 16, 2011)




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## jayw81 (Dec 11, 2011)

Hi guys, just an update









We are in the new house now and as soon as everything is unpacked, progress will resume!

Looking forward to moving on with this project and bringing it to completion..

Jay


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## rockslinger (Nov 16, 2010)

*Looking forward to seeing the progress







*


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