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One Hand Primable Blaster - Writeup

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#1 diamondbacknf1626

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Posted 26 July 2011 - 11:36 PM

Okay, so first things first, this project has been goin’ on for awhile. The idea was to make a blaster that was able to be primed with one hand. The thought behind this being that you could wield two blasters at once. As I’m sure many of you have tried, maybe just in fun, tying a string to the plunger rod of a blaster and then to your shoulder gives you a “one hand primable blaster.” However, an inherent problem with this design is the fact that it requires you to fire the blaster from an arm-bent position, due to the fact that the string is taught with your arm outstretched, and thus wouldn’t allow the plunger to travel forward. Because the arm-bent position is such an awkward way to fire your blaster, I wanted to reverse it entirely. Here is the first iteration of the design:
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The blaster essentially operates by pulling the handle towards your body in order to prime, and pushing it away to return the handle to the forward most position and ready to fire. A strapping system is to be set up to secure the blaster to your shoulder while you push the handle forward, so that the whole blaster doesn’t move forward when you push. This design had a couple issues. 1. I hadn’t developed a viable strap yet. A simple loop would just slip off of my shoulder, causing lots of problems. Also, the blaster was longer than it had to be. The shorter the better, in this case. Thus, the redesign:
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The re-model features a 2” PVC plunger tube, which allows a much shorter plunger tube length, yet yields the same (in this case even larger) air output. There is a carabiner clip at the back that clips onto the strap setup that we’ll discuss later. One of the goals of this design was to step up the PVC to 2” PVC, while still maintaining a standard sized Rainbow catch. One of the reasons for this was because I wanted to be able to mount the catch in opaque pvc. If It was made to fit 2” PVC, it would’ve been difficult to mount it properly in place. In the 1 ¼” PVC, the front edge of the catch is right at the front edge of the 1 ¼” PVC, so it’s rather easy to estimate. Anyway, let’s get to it.

Materials
-2” PVC end cap
-20.5” of 2” PVC (this can vary based on your arm length if you’d like. All that needs to remain the same is where the cuts/holes are drilled with relation to the front end of the PVC). I chose to use opaque PVC for this portion as well as for the 1.25” PVC, simply because it’s much less expensive, and I wanted to show that it could be done with said parts.
-14” of 1 ¼” PVC (See above)
-¾” thick wood (I used poplar board)
-2” PETG (9245k51 from McMaster), or you could probably use 1.5” Thin-wall PVC
-4 3/8” 6-32 set screws (McMaster part number 92311A146)
- 3/16” polycarbonate sheeting (McMaster part number 8574K27)
-¼” polycarbonate sheeting (McMaster part number 8574k28)
(You’ll only need a bit of each of the above, but if you’re starting fresh, you’ll have to buy one 12”x12” sheet of each).
- ~8 ½” of ½” round nylon rod (McMaster part number 8541k18)
- ~5” of [k26] (or [k25] I guess) spring from McMaster Carr (9637k26(25))
-2” of steel rod (McMaster part number 9120k9)
-Spring for the catch.
-Braided polyester cord from your local hardware store
-Some sort of material for a strap (~$20). I used a Camelback, which cost $50, but this is strictly optional.
-3x ½” 6-32 machine screws (McMaster part number 90272A148)
-2x 1 ¼” 6-32 machine screws (McMaster part number 90272A151)
-1x 6-32 Hex Nut (McMaster part number 90480A007)
-Skirt Seal (McMaster part number 9562k51)
-2 times ¼”x¼” round nylon spacers that fit a #6 screw
-1 1” 6-32 thread machine screw. Don’t get this from McMaster, get it from your local hardware store…I never need 1” ones, just for this application.
-A couple inches (this you’ll need to just figure by yourself, because each is different) of: ½” CPVC, ½” PVC, ½” PVC coupler, 1 ¼” Internal PVC Coupler, 1 ¼” PVC, and (2x) 1 ¼” Coupler. Here’s a pic to help:
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All in all, this should come out to a total cost per blaster of ~$39.27, so about $40. This is rather good, considering that half of the cost consists of the strapping material. This could really be replaced by something as simple as an old backpack that you have around, so long as it has a chest strap. Easy peasy.

Tools that I used:
-Scroll saw
-Phillips head screw driver
-Hex Driver
-Drill/Drill bits
-Rubber mallet
-6-32 tapping bit
-Dremel (Just to cut the spring)
-Tape-measure
-Sharpie Marker (I probably use this more than anything. Red is a good color choice. It shows up clearly on all of the build materials)
-Band Saw
-Belt Sander
-Sand paper

(These tools might not all be necessary, but this is what I used throughout the build)

So anyway, let’s get to work. First things first, cut everything that you need to cut.
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^Each of the rings of PVC that I mentioned earlier.

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^2” of 2” PETG

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^20.5” of 2” PVC, 14” of 1.25” PVC, 8.5” of ½” Nylon Rod

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^3 Polycarbonate circles (Disregard one of the smaller ones). One should fit inside the skirt seal, and two should be just barely larger than the diameter of the bottom of the skirt. I don’t have specific measurements for these, simply trace them out on your polycarbonate sheet, and cut them. One of the larger and the smaller circles should have a ½” hole drilled through them, while the third should have a 5/32” hole drilled through. All should be cut from ¼” polycarbonate. I found that if the inside piece is a bit smaller, you can pinch down on it real nice with the two outside pieces.

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Cut your handle. I used Ryan’s templates found here and modified them as you see.

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Cut 2” from the steel rod.

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Cut 5” of your [k26] spring.

Also cut the piece seen here:
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Also cut the polycarbonate side plates as well as the trigger. You can find templates for both of these in Ryan’s thread as well.

And now to the more difficult bit, machining your catch. We’ll get back to those other parts later, go ahead and through them aside.

By more difficult, I don’t mean to say that it’s actually difficult to do, but it’s just a wee bit more difficult than the other pieces. Get a hold of your templates, found here.
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Cut one set out, and stick it onto your ¼” polycarbonate:
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Before drilling your holes, take an awl (or center punch, as some have mentioned)and tap it with a mallet onto the center of each hole-to-be. This helps to seat your drill bit more centered on the part.
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Then, go ahead and drill each hole with the proper drill bit. The back plate should have a 9/16” hole for the larger hole, and 5/32” holes for the smaller ones. The other should have a ½” hole for the large one, as well as 7/64” hole for the smaller ones and should be tapped.
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Here are some pics of the completed parts:
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A file is your best friend here. Make sure everything is nice and clean, and fit’s the plunger rod nicely.

Here is the catch assembled with ¾” screws:
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Edited by diamondbacknf1626, 27 July 2011 - 03:56 PM.

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QUOTE(TxNerfer @ Nov 13 2010, 12:42 PM) View Post

Hey...I got a crazy idea: how about you stop all that sigging stuff? It's not even my thread and it annoys me.

#2 diamondbacknf1626

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Posted 26 July 2011 - 11:39 PM

Alrighty, now that that’s out of the way, let’s take a step back, and finish some other parts. Grab your plunger rod, and cut your catch notch ~2.5” from the front of the rod.
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This is variable based on what spring you’re using, but that’s what I used for mine. Then go ahead and drill a 3/16” hole through the side of your plunger rod, 1.25” from the back. This is for the steel priming bar. Then, go ahead and drill a hole large enough for whatever sort of string stop you choose to use. This should be .5” from the back, down through the top. Also, drill a 7/64” hole in the front end of the rod, which you should then tap with a 6-32 tapping bit.

Now, all those rings of PVC and PVC couplers stack together like so:
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Be sure to orient them all correctly. The ½” CPVC should get hammered into the ½” PVC, and then put into the whole smorgasbord of PVC. Wrap some e-tape around dat whole chunk and then put it into the 2” PVC endcap. This will help you mark and drill a centered 5/8” hole in your endcap.
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Slather the top side (the side with CPVC protruding) with plumbers goop and feed the CPVC through the hole.
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Now, use a vice, clamp, mallet, or whatever means of superpower that you so please, to get the other bit of ½” PVC onto the protruding cpvc. This will lock everything together and allow the goop to set while still continuing work.
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Okay, let’s finish up the handle. Your handle should be about 2” across on top. Try to maintain this even when sanding. DO NOT over-sand the handle. You need to make sure you leave enough room for the screw holes. What you want is to equally space the screw holes while leaving just enough room on either side so as not to split the wood. A good split is ½” between each (edge-½”-hole-½”-hole-½”hole-½”-edge). Here is what I did:
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Now, once you have that, drill the same pattern on your priming slide. You’ll need to also drill some clearance holes on top for your screw driver. I use 3/8” holes for that bit. Also, what you’re going to need to do is countersink the bottom holes. This is a bit tricky. I use the same 3/8” drill bit for this portion. Take said drill bit, and set your drill on the lowest setting so you have the most control over it. You don’t want it ripping through the bottom hole. Just lightly grind out the inside of the 2” PETG/1.5” thin wall so that there is room for the head of the screw to fit in. If there are any stubborn bits of PETG sticking up, never fear, the screw head will squeeze those down when you put them in. This should look like this:
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Now that that’s done, go ahead and secure the handle with some 1 ¼” wood screws:
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Super sturdy.
Now, to the rear portion of the blaster. First is the worst…slots. They’re not too bad if you do them this way, just a tad time consuming. Start out with two straight lines, one on either side your 1 ¼”
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The lines should start about 2 ¾” from the front, and be 4” long. Now, trace the lines, and drill lots of 3/8” holes into the PVC. Here’s how it should start to look:
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Let’s pretend that they turned out like this after taking a scroll saw to them and completing the slots:
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Heehee…

Now let’s work on mounting the catch. The catch will be mounted in the rear portion of blaster, the 1 ¼” PVC. One of the goals of this design was to step up the PVC to 2” PVC, while still maintaining a standard sized Rainbow catch. One of the reasons for this was because I wanted to be able to mount the catch in opaque pvc. If It was made to fit 2” PVC, it would’ve been difficult to mount it properly in place. In the 1 ¼” PVC, the front edge of the catch is right at the front edge of the 1 ¼” PVC, so it’s rather easy to estimate. Anywho, do your standard Rainbow catch mounting. Stick it into the end of the 1.25” PVC, drill 4 holes into it with a 7/64” drill bit, remove the catch, and tap both pieces separately:
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The above picture is from a later step, but that’s the basics of what it looks like once it’s in there.

Now we’re just about getting to that step though…
Go ahead and take the ¾” segment of 1 ¼” PVC coupler from before, and stick it over the front end of the 1 ¼” PVC, where the catch is. You can just glue this, screwing it in place isn’t really necessary. Really, glue isn’t really necessary.
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See that dot? That dot is meant to correspond with the bottom of the catch, right where the screw will go for the sliding portion of the rainbow catch. It should be 3/8” from the front. Go ahead and drill out that hole with a 5/32” drill bit. Make sure to stop drilling before f’ing up your catch. It’s not really that hard, but it’d be a bummer if you f’d it up, so I’m warning you now. Now, wrap most of the 1 ¼” coupler segment with e-tape, avoiding the portion where the catch screw goes. This will simply keep the rear piece centered in the front piece:
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Okay, now go ahead and slip your handle onto the 1 ¼” PVC. Make sure it slides nice and smooth-like.

Also, now would be a good time to make your plunger head. Stick one large and one small circle on, followed by the skirt, and then followed by the third circle, which should be tightened heavily onto the rod with a 1 ¼” machine screw. (Please DISREGARD any rubber biznis you see on the front of the plunger head from this point forward. It was an attempt at a check valve in the plunger head that is still going through development. I abandoned the project temporarily, and actually built a new plunger since these pictures were taken.) So now, feed the spring onto the rod, and then the rod through the catch, and then the 2” steel bar through the slots and the rod. Should look like this:
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I know it looks a little crooked…that’s because it is. That’s because it’s not really contained by anything yet, and is free to bend back and forth.

Now, drill 2 holes in your T. These should be the same size as the one you drilled through the top of the plunger rod. These will be for your string stop. Make sure you’ve allowed enough clearance for the 2” PVC to but up against the T. Here’s a quick look at what it’ll look like eventually:
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Now, feed the string through one hole in the T, through the plunger rod (this bit could take some coercing, just work with it), and out the other hole in the T. Then shove the T onto the end of the 1 ¼” PVC, wrap it with enough tape to fit slightly less than snug in 2” PVC, and you’re done with the rear part of the blaster! That’s most of the work, so you’re actually almost done.
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QUOTE(TxNerfer @ Nov 13 2010, 12:42 PM) View Post

Hey...I got a crazy idea: how about you stop all that sigging stuff? It's not even my thread and it annoys me.

#3 diamondbacknf1626

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Posted 26 July 2011 - 11:41 PM

Now for the plunger tube. The beauty of this design…or, well, one of the beauties of the design, is that the plunger tube is also the sheath for the priming slide. This means that the whole blaster is just one uniform size, which makes it look nice and clean. First off, cut off just a small bit of the 2” PVC, just enough for the handle to slide through. Super easy to do, just slide it along through the bandsaw:
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Now go ahead and drill two holes in your plunger tube. One, which should be 3/8” from the end of the slot, is to be 5/32”. The other, 2” from the slot, should be 7/64” and tapped.
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Now go ahead and drill and tap a 7/64” hole through the small square block of wood, and screw it onto the plunger tube like so:
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(I did it backwards, countersinking a hole in the plunger tube, and then running a screw in through the top. This way is probably way easier.)

Once that’s done, mount the rest of your trigger, and slide the back piece containing the plunger into the front piece. Now, screw in your catch screw w/ spring, put the endcap on the end, with your super duper telescoping bushing set-up, and hoorah! You’re done. Well, almost. Go ahead and put a screw into the back end of the 2” PVC, the 1.25” T, and the 1.25” PVC just to hold everything together.
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Yayay, applause applause. To be honest, it probably took you longer to read this writeup than it will to make the blaster.

Now, for the most important part of the whole design. The strap. Here are some pictures of the way I currently have it rigged:
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The blaster is first primed to put some slack into the string stop.

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The carabiner clips onto the string and then clips onto the camelbak (or whatever sort of strapping system you choose to use):
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Again, this is just my current setup. As soon as I get access to a hand drill, I'm going to drill a hole to fit the carabiner just below the bottom hole for the string stop. The carabiner will then be fed through there, and will thus be fixated in one position, rather than be able to move backwards and forwards a bit like it does currently. That is the way that this should be done, building your own. Like I said, I just don't have access to a drill right now.

This video gives an overview of the strap system utilized, as well as potential alternate strap systems. I used a camelbak, but as I discuss in the video, there are much cheaper alternatives that will achieve the same effect:

http://www.youtube.com/watch?v=n0IjfPF_7ZM

Let me know what y’all think, and wish me luck!

Edited by diamondbacknf1626, 27 July 2011 - 11:48 AM.

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QUOTE(TxNerfer @ Nov 13 2010, 12:42 PM) View Post

Hey...I got a crazy idea: how about you stop all that sigging stuff? It's not even my thread and it annoys me.

#4 mysterio

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Posted 27 July 2011 - 01:01 AM

Wow, great job. Long writeup though.

How about slam-fire? [insert troll laughter.]

Anyways, ranges?
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If two powerful is a problem then just go with one powerful. I guess this style of hopper will work even beyond three powerful..


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#5 Buffdaddy

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Posted 27 July 2011 - 01:04 AM

Again, awesome. As stated in chat by people unnamed, the one handed priming isn't necessarily a big thing for most nerfers. But the dual wielding........

WIN
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#6 taerKitty

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Posted 27 July 2011 - 01:07 AM

Wow, great job. Long writeup though.


Long writeups are good. This writeup is good. Ugh. Caveman like.
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#7 RedShot

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Posted 27 July 2011 - 08:27 AM

Very nice! I am going to look into making one now! It doesnt sound TOO overly complicated either so yay!
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#8 Phree Agent

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Posted 27 July 2011 - 09:24 AM

Ahh, I remember the ancient prototype plans we looked over one night on the IRC! It is even prettier than I imagined. Great to see it come through its various stages of production, and the write up was excellent.
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#9 diamondbacknf1626

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Posted 27 July 2011 - 11:55 AM

Wow, great job. Long writeup though.

How about slam-fire? [insert troll laughter.]

Anyways, ranges?


Thank you. Yes, it is quite long...I wanted to be thorough. As for ranges, I discuss them in the video. I still need to toy around with dart barrel fit. It has the potential to shoot as far as the top springers in town, soon as I find the proper barrel.

Again, awesome. As stated in chat by people unnamed, the one handed priming isn't necessarily a big thing for most nerfers. But the dual wielding........

WIN


Thank ya :) Yeah, the idea is to dual wield these blasters. Or, if you do not have two, you can wield a pistol with your other hand, and use it to fend people off while reloading.

Long writeups are good. This writeup is good. Ugh. Caveman like.

Agree on both counts. Nicely done, db


Thank you to you both.


Very nice! I am going to look into making one now! It doesnt sound TOO overly complicated either so yay!


It's really not difficult to make at all. Most of my time was spent figuring out the proper dimensions to use for each piece, which I've already done for you. The build itself is rather simple.

Ahh, I remember the ancient prototype plans we looked over one night on the IRC! It is even prettier than I imagined. Great to see it come through its various stages of production, and the write up was excellent.


Haha, yeah, way back. Thanks man, I appreciate it.

Anyway, I updated the third post of the writeup with pictures and a bit of description regarding the current setup to attach the blaster to the strap. As written in said post, this is only temporary until I get access to a drill. Doing it this way is close enough that it gives a very good idea of overall function (it will actually be even better once I get that drill).

Edited by diamondbacknf1626, 27 July 2011 - 11:56 AM.

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QUOTE(TxNerfer @ Nov 13 2010, 12:42 PM) View Post

Hey...I got a crazy idea: how about you stop all that sigging stuff? It's not even my thread and it annoys me.

#10 Buffdaddy

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Posted 27 July 2011 - 02:21 PM

The more I think about it, The better this becomes. If I'm thinking right, then by all means this is probably the most stable platform yet. You can support it with your shoulder and off arm, and then cock and shoot with your main arm, kinda like a bolt action rifle. You can be aiming the whole time!
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#11 diamondbacknf1626

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Posted 27 July 2011 - 04:44 PM

The more I think about it, The better this becomes. If I'm thinking right, then by all means this is probably the most stable platform yet. You can support it with your shoulder and off arm, and then cock and shoot with your main arm, kinda like a bolt action rifle. You can be aiming the whole time!


This is very true. The blaster is totally usable with two hands, and actually excels in that area. You are quite right in that its very, very stable.
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QUOTE(TxNerfer @ Nov 13 2010, 12:42 PM) View Post

Hey...I got a crazy idea: how about you stop all that sigging stuff? It's not even my thread and it annoys me.

#12 Themeekus1

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Posted 10 October 2011 - 09:59 PM

Can I buy your prototype? Im in the continental U.S so shipping wont be much of a problem. Name a price

#13 HasreadCoC

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Posted 11 October 2011 - 07:51 AM

Can I buy your prototype? Im in the continental U.S so shipping wont be much of a problem. Name a price

Not attempting to backseat mod here, but it might be better to PM him rather than post here, as this is an older topic. He'll be more likely to see it if it's in his PM box that way.
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#14 Langley

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Posted 11 October 2011 - 06:36 PM

This is what PMs are for. I'll abstain from closing the topic for the remote possibility someone may want to add something worthwhile to it.
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You can poop in my toilet anytime champ.

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#15 Themeekus1

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Posted 12 October 2011 - 06:24 PM

Not attempting to backseat mod here, but it might be better to PM him rather than post here, as this is an older topic. He'll be more likely to see it if it's in his PM box that way.


Thanks for the tip, I'll make sure to correct it in the future.


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