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the Lowes And Walmart airgun
homemade writeup airgun

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#1 Ivan S

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Posted 02 June 2014 - 01:53 AM

This is an easy, low-overhead, and safe airgun build. It uses entirely parts from Lowes and Walmart, and requires only a saw, drill, hammer, pliers, scissors and a screwdriver to assemble(no dremel!). Tony Stark couldn’t just build this in a cave, he could build it in a cave with his eyes closed.
14325236342_e3e5617514_o.jpg

Noob suitability
The ease of build comes from twist fittings and the complete lack of precise cuts. This gun uses twist fittings (technically known as national pipe taper fittings, or NPT) unlike most NIC air guns which use slip fittings and PVC cement. PVC cement is a powerful solvent weld(similar to glue), which has toxic fumes, is totally permanent, takes practice to use correctly, and requires and extra $10 in chemicals most of which a noob won’t even use in this build. Twist fittings are easy, cheaper, and (crucially) you can disconnect them if you mess up.
This gun has an IKEA philosophy, meaning you simply buy the pieces and connect them together. This doesn’t apply to every single step, there are a few times you have to cut pipe and one fitting which needs to be cut in half. But compared to the myriad of cut slots, half pipes, catches et cetera which are common in other builds, this is particularly suited for the noob who doesn’t have a lot of tools or experience slicing up plastic.

Safety
Fear, uncertainty and doubt often surround airguns with regard to safety. This gun uses an over pressure release valve(OPRV) taken from the air max one(aka panther) to ensure that it can never be over pumped to a pressure dangerous to the user or their target. It is true that pvc pipe is not approved for use with pressurized gas in building codes, because if a plastic pipe holding pressurized gas bursts, it can shatter and send pieces flying. However, this gun operates at only 35psi, less than 15% of its weakest fitting’s maximum operating pressure, and less than 3% of its burst pressure[1]. This makes the probability of bursting so remote, that for me it is an acceptable risk.

So enough talk, let’s build.

You will need:
Parts by where to find them:
Walmart
Bell airstrike dual action pump
Buzz bee air max one (formerly known as the panther)
Soft Soap(yup)

Lowes
Plumbing section:
5’ long ½” cpvc pipe
2’ long ½” pvc pipe
1/2” nipple 12” long
2x ½” nipple 3” long
2x ½” female to 1” male bushing
½” npt male x ½” npt female “street” elbow
½” npt x npt elbow
1” npt coupler
3x ½” tee
½” npt tee (all three sockets npt)
½” cap
½” x 3/4” bushing
¾” ball valve
Teflon tape aka PTFE thread seal tape


Hardware aisle:
¼”-5” hex bolt
#6 x ½” sheet metal screws, smallest pack


Specialty hardware drawers:
¼-20 well nut
Bolt cap

Elsewhere in Lowes(it varies, ask an attendant):
JB epoxy weld

Parts by subsystem
Pump:
Bell airstrike dual action pump
JB weld
¾” female to ½” npt male adapter

OPRV:
Another ¾” female to ½” npt male adapter
Buzz bee air max one (formerly known as the panther)
JB weld(the same as before)

Tank/body:
½” npt tee
½” male npt to ½” female npt elbow(aka street elbow)
½” female npt to ½” female npt elbow
½” 12” long nipple
½” 3” long nipple

Trigger:
2x ½” female npt to 1” male npt bushing
1” npt coupler
2x ½” tee
JB weld
½” dia 12” long nipple (a second one)
¼-20 well nut
¼”-5” hex bolt
Soft soap(for the miniature spring in the pump)
½” cap

Barrel/clip:
5’ cpvc pipe
2’ ½” pvc pipe
½” coupler
½” to ¾” bushing
¾” ball valve

Overview
It’s a basic air gun based on 3DBBQ’s madghost[2], with modifications. The main ones are an oprv, a well nut trigger[3] and noob friendly construction. If you’re ever unclear on how everything fits together you can look at this diagram.
14140331498_f6ed8f0261_o.png
The build relies heavily on twist joints, so here’s a guide: You will need a male fitting, a female fitting, and teflon tape. Teflon tape is variously known as teflon tape, thread tape, thread seal tape, or PTFE tape. Wrap your tape around the male fitting 3-5 times. It’s important you wrap it in the right direction, so make sure the end of the tape points in the same direction as the end of the thread on the male fitting.
14140382950_122f786236_o.jpg14140474897_06724905b5_o.jpg
Then put your female fitting on and turn it as much as you can with your hands. Only turn it by the fitting though, because if you turn for example by the end of the pump, it will act as a lever and give you enough force to crack the fitting.
14140474567_cd7544b9fc_o.jpg
Teflon tape doesn’t actually form a seal between the fittings, rather it reduces the friction between the fittings which lets you turn them more times and make a seal that way.

Also, some plumbing vocab. Nipple: A length of pipe with male threads at both ends
Bushing: a fitting that wraps around one pipe while being wrapped around by another fitting. They’re usually circle shaped, and can be either slip or threaded.
Adapter: a fitting that connects two pieces whose sizes don’t allow for a bushing
NPT: National pipe taper, aka “twist” or “threaded”. Pipes and fittings which are connected by threads instead glue or friction.

Trigger System
This gun’s trigger is based on thedom21’s WNTS(well nut trigger system), but the well nut is inverted to increase air flow and the bolt is stabilized by a second tee.
First, remove the spring from your soft soap pump with scissors. You can get little springs like that in packs at Home Depot, but this build is limited strictly to Lowes and Walmart, so a creative solution is necessary.
14304230656_d6ed2ae3e2_o.jpg
Drill ¼” holes in the center of two of your tees. Always use eye protection with power tools!
14140382400_e3e7255099_o.jpg
Then cut both sides of a tee along the red line. If you’re using a hand saw, hold the fitting with pliers, because a saw can easily slip on a round fitting like this one.
14326306474_150347e75d_o.jpg
Cut a roughly 1-1/8” stub off a 3” nipple, then assemble the hex bolt, the soap spring, the sawed tee, the whole tee, the nipple stub, a ½”-1” npt bushing(mine is orange, yours will be white), and the well nut as shown. You can also add a screw cap to make the hex bolt more comfortable on your trigger finger.
14140382240_50687e4e8f_o.jpg14140334498_0fcb15293b_o.jpg
Mix equal parts of JB epoxy weld goo with a paper clip for at least a minute. Center the well nut with the hole in the bushing. Apply JB weld between the tees, you can wipe off any excess with your finger(jb weld is non-toxic).
14326309194_f1bc484110_o.jpg14325238472_ee96b8eb8e_o.jpg
Double check that the well nut is centered on the bushing. Once the epoxy cures(12 hours), the well nut will be held centered and keep a good seal. I left mine in a piece of pvc pipe, but you can use a cup or anything that will hold it upright.
14325237412_c73e8d5a71_o.jpg
Add a dab of epoxy on the end of the well nut to seal the threads.
14347188503_c9ce35611e_o.jpg


Over pressure release valve
The OPRV is a device that vents air from the tank to prevent it from going above a given pressure. It prevents your gun from being a shit cannon or a pipe bomb. For noobs unfamiliar with the concept, a shit cannon is an exercise in dick-waving where a gun shoots as far as possible, which is usually dangerous, encourages boring play, and isn’t even useful. Ariguns are famous for being used as shit cannons, but this gun is an exception. I chose a common and cheap gun to salvage an oprv from, and adjusted the tank size so that this gun shoots on the same level as a standard spring powered homemade.(210fps, as measured by 60 frame per second camera)
Unscrew and open up your air max one/ panther. Yours probably won’t have a mediocre paintjob.
14303860646_a34dfaab47_o.jpg
Cut along the red lines to remove the oprv. Be careful not to cut into the cylinder itself!
14140470797_6440fb59c3_o.jpg
Place the oprv in the socket of a ½”npt x ¾” adapter like shown and slather the edges in JB weld. Be careful not to put it in backwards or cover up the hole.
14347191253_9607bf42c2_o.jpg

Pump
Unscrew the nozzle bit from your pump. Sometimes the threads are glued, so you may need to saw at the black part it a bit to get it off.
14140335519_af0e05d065_o.jpg
Apply JB weld around the edges of the socket of your other ½”-3/4” adapter, and around the edges of your pump base.
14347192053_af322e59e3_o.jpg
14140383710_48dc7ff2b5_o.jpg
Insert the pump into the adapter with a twist motion, wipe off excess epoxy, and leave it upright to cure.
14140383670_2746f9941e_o.jpg

Barrel and clip
This is a basic RSCB clip and cpvc barrel, that you'll find on most guns without internet parts these days.
Cut a 1” stub of pvc pipe and a 12” length of cpvc pipe.
14140381030_ed06d1f6e3_o.jpg
Ream(increase the inner diameter of) the pvc stub with scissors until the edge of the cpvc fits into the edge of the pvc.
14140472707_2a5f8a2168_o.jpg14323665841_b27f67a9dd_o.jpg
Use a hammer to force the cpvc the rest of the way down the pvc stub. Once you do this, ream the open end of the pvc so darts can slide into the barrel. Whoops, my pvc stub changed color. Ignore that please.
14303856726_e384ab9d65_o.jpg
Connect your newly made barrel, a tee, a 12” length of pvc pipe, the ½”-3/4” bushing and ball valve together like this.
14347187903_0c931e16f6_o.jpg14140330459_9cf9366039_o.jpg
Cut two 1.5” stubs of pvc pipe and use one of them to connect the barrel assembly to the trigger assembly. While you’re at it, use the other stub to connect a cap to the other side of the trigger. Drill 1/8” holes in these two places and screw your sheet metal screws into them. This will keep your barrel from swinging around while running.
14140380090_e4d7fcbfd8_o.jpg

Final assembly
Now that you’ve got all your subsystems together, all that’s left is to use the remaining fittings to connect your subsystems. In case the diagram isn’t clear, from the trigger it goes: 1” coupler, 1/2”-1” bushing, 12” nipple, twist elbow, 3” nipple, street elbow, twist tee, pump and oprv.

Use
Use is pretty straightforward. Open the ball valve and drop in darts until the pvc pipe is full then close it, that’s your clip. Put the butt against your dominant shoulder with your non-dominant hand on the pump and your dominant on the trigger. Tilt the gun down slightly and pump six times. At the end of the sixth pump you’ll hear a slight hiss, that’s the oprv signaling the tank is at max capacity. Then just aim down the barrel and press the hex bolt to fire.

Any questions, please ask. If its past the statute of necro limitations shoot me a pm.

Sources:
1.http://www.engineeri...ures-d_796.html
2.http://nerfhaven.com...showtopic=21427
3.http://nerfhaven.com...showtopic=21530


Edited by Aeromech, 23 November 2015 - 02:59 AM.

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#2 PBZ

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Posted 02 June 2014 - 12:50 PM

Based off of the MadGhost, have you seen the american version, the WNTS?
Quick question to double check- is the second T in the trigger section just to stabilize the trigger bolt? By flipping the well nut I would think it wouldn't be necessary since it i think would seal a lot easier?
Ranges? FPS? Usability? You don't have any info on how the OPV affects these. Wondering if people that build this are going to drop it in favor of borrowing a blaster.
Great write up, good job on finding a way to get an OPV in there!
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#3 Phree Agent

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Posted 02 June 2014 - 02:15 PM

I made a Mad Ghost (Similar design to this) and the trigger pull was pretty difficult since it is essentially counteracting all of the pressure in the tank. What kind of force does your require? I was planning on creating a lever to aid my trigger pull similar to the one used on air hose nozzles, but never got around to it.
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#4 Ivan S

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Posted 02 June 2014 - 02:56 PM

Based off of the MadGhost, have you seen the american version, the WNTS?
Quick question to double check- is the second T in the trigger section just to stabilize the trigger bolt? By flipping the well nut I would think it wouldn't be necessary since it i think would seal a lot easier?
Ranges? FPS? Usability? You don't have any info on how the OPV affects these. Wondering if people that build this are going to drop it in favor of borrowing a blaster.
Great write up, good job on finding a way to get an OPV in there!

I covered most of this in the write-up, but I'll reiterate. This gun draws heavily from the WNTS, it is referenced and cited. Speed is 210fps as measured by a 60 frames per second video camera. Usability is simple, just tilt, pump, aim, and fire. The opv/oprv is designed to limit FPS to a safe level, but doesn't effect usability at all.
The well nut is inverted to increase air flow out of the tank. The hex bolt has less than a third of the cross section of the well nut, so this way it restricts airflow less. You are correct, the second tee then serves to stabilize/center the well nut, which can move more without being held in place by it's end inside the bushing. It's also worth noting that the original WNTS required an o-ring for seal, probably because the wellnut wasn't held flat against the bushing by anything. An o-ring the perfect size would be hard to find at Lowes, and this build eliminates that.
What specifically makes you think someone would drop this for a loaner? It shoots as far as most springers and is easy to use, so I consider it competitive.
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#5 Ivan S

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Posted 02 June 2014 - 03:01 PM

I made a Mad Ghost (Similar design to this) and the trigger pull was pretty difficult since it is essentially counteracting all of the pressure in the tank. What kind of force does your require? I was planning on creating a lever to aid my trigger pull similar to the one used on air hose nozzles, but never got around to it.


Thanks for bringing this up, I've also experienced that problem with the mad ghost. But, when you use a well nut trigger instead of a check valve trigger, the trigger pull becomes unbelievably easier. To say why would be speculation, but I've built several of both and it's definitely the case.

Edited by Ivan S, 02 June 2014 - 03:02 PM.

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#6 Sam-underscore

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Posted 02 June 2014 - 04:06 PM

Nice writeup! Have you tried making a hoppered version?
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#7 Nerf Gra

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Posted 02 June 2014 - 04:28 PM

This write up is pretty great. Cool blaster.

For me the best part is the diagram you made. I could build the thing just on that one picture. Its perfect. The NIC needs more of that sort of thing. I'm going to build one of these tomorrow.

Edit: this might be silly but how do you actually hold it with your trigger hand? It looks like it would be uncomfortable/ slightly difficult to hold.

Edited by Nerf Gra, 02 June 2014 - 04:32 PM.

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QUOTE(VelveetaAvenger @ Dec 6 2010, 12:14 AM) View Post

Maybe there's no Mcmaster, but you could make the first coconut airtank.


#8 Draconis

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Posted 02 June 2014 - 04:35 PM

This would be very easy to convert to a lever trigger, if the pull were too heavy for you.
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#9 Nerf Gra

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Posted 02 June 2014 - 05:02 PM

I'm not worried about the Tigger pull but merely in hand comfort. I just don't know if there's enough there for my fingers to hold onto
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QUOTE(VelveetaAvenger @ Dec 6 2010, 12:14 AM) View Post

Maybe there's no Mcmaster, but you could make the first coconut airtank.


#10 MAV13

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Posted 02 June 2014 - 08:45 PM

I'm not worried about the Tigger pull but merely in hand comfort. I just don't know if there's enough there for my fingers to hold onto


You could actually shape this ergonomically with different pieces of pipe and fittings, both the air tank and air outlet can be in any configuration you'd want since it's just PVC. I'm debating making one of these but just shaping it like a Mad Ghost myself.
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#11 PBZ

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Posted 03 June 2014 - 03:49 PM

I covered most of this in the write-up, but I'll reiterate. This gun draws heavily from the WNTS, it is referenced and cited. Speed is 210fps as measured by a 60 frames per second video camera. Usability is simple, just tilt, pump, aim, and fire. The opv/oprv is designed to limit FPS to a safe level, but doesn't effect usability at all.
The well nut is inverted to increase air flow out of the tank. The hex bolt has less than a third of the cross section of the well nut, so this way it restricts airflow less. You are correct, the second tee then serves to stabilize/center the well nut, which can move more without being held in place by it's end inside the bushing. It's also worth noting that the original WNTS required an o-ring for seal, probably because the wellnut wasn't held flat against the bushing by anything. An o-ring the perfect size would be hard to find at Lowes, and this build eliminates that.
What specifically makes you think someone would drop this for a loaner? It shoots as far as most springers and is easy to use, so I consider it competitive.


Please excuse my first questioning if it wasn't clear or you thought it rude.
A collection of responses and notes on your other responses:
I asked about the WNTS because it's only cited once in the write up and I missed it the first time through, so it may be heavily based off of it but it's not heavily referenced or cited (you could have put it upfront instead). Great idea on turning the well nut around, you are correct about not having to push against the pressurized tank to open the valve. The original WNTS well nut valve used an oring because the well nut did not have the surface area to seal on the face of the fitting, it sealed in the end of the pipe, and it was held shut both by the trigger spring and the pressure of the tank. Finding an o-ring that fits for the WNTS build was literally as easy as finding one that fit around the well nut, but flipping negates that completely, well done again.
I am familiar with how to use this type of blaster, I have several WNTS's. I was asking about stuff like ranges, fps, etc being affected by the OPV because even if its a super easy build, if its still outclassed by 20 feet at every turn its going to be replaced with a loaner during competitive wars. Do you have any comparison data to this blaster's stats if you do not have an OPV at the same number of pumps? I understand that would be like building a WNTS, but with the well nut turned around it may probably outclasses the WNTS capabilities due to increased airflow. And you still havent answered on the ranges- can you get them?

Side note, from reading through the write up a few more times- you mention not buying glue because "it requires an extra $10 dollars in chemicals that are [negated through this build]". Good job on not needing the glue, but what makes it "hard to use" for a newcomer, and what makes twist fittings any safer? I understand that if you get a bad glue joint it would leak; and with the OPV in the system, you won't reach pressures high enough to blow a joint. The only places I have ever broken my WNTS's is actually the twist in fitting, sometimes while pressurized...
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#12 Ivan S

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Posted 14 July 2014 - 01:07 AM

Sorry to get back to you guys late, classes etc.

Nice writeup! Have you tried making a hoppered version?

Thanks! It works just fine with a hopper, I use an RSCB in the writeup purely to avoid requiring a wye.

You could actually shape this ergonomically with different pieces of pipe and fittings, both the air tank and air outlet can be in any configuration you'd want since it's just PVC. I'm debating making one of these but just shaping it like a Mad Ghost myself.

Definitely, there is a lot of flexibility in layout. I prefer the tee shaped handle as opposed to the elbow because it's easier to drill a straight hole in a tee than an elbow, but either can work.

This might be silly but how do you actually hold it with your trigger hand? It looks like it would be uncomfortable/ slightly difficult to hold.

Good question, I hold it like this:
Posted Image
It's comfortable for me, but if you want more hand room you can make the stub between the tee and cap longer. Fill it with hot glue if you're worried about dead space.

I am familiar with how to use this type of blaster, I have several WNTS's. I was asking about stuff like ranges, fps, etc being affected by the OPV because even if its a super easy build, if its still outclassed by 20 feet at every turn its going to be replaced with a loaner during competitive wars. Do you have any comparison data to this blaster's stats if you do not have an OPV at the same number of pumps? I understand that would be like building a WNTS, but with the well nut turned around it may probably outclasses the WNTS capabilities due to increased airflow. And you still havent answered on the ranges- can you get them?

I took some readings without the oprv and with the same number of pumps, muzzle velocity is the same.
I haven't done range tests, but if you want to match up velocity with range, you can look here and here. The chart shows 210fps is pretty standard for competitive guns; it matches to about 80 feet when fired perfectly level, which is roughly equivalent to the 100 foot claim people give with a slight(often unintentional) angle. If you want more range, you can always make the tank and barrel bigger.

Side note, from reading through the write up a few more times- you mention not buying glue because "it requires an extra $10 dollars in chemicals that are [negated through this build]". Good job on not needing the glue, but what makes it "hard to use" for a newcomer, and what makes twist fittings any safer? I understand that if you get a bad glue joint it would leak; and with the OPV in the system, you won't reach pressures high enough to blow a joint. The only places I have ever broken my WNTS's is actually the twist in fitting, sometimes while pressurized...

Twist fittings aren't safer, but they are better for noobs because they aren't permanent. For example, if you pvc cement your OPRV subsystem to the tank only to find out that it leaks, then the whole assembly becomes useless. But with twist fittings, you can just replace the bad subsystem with a working one.

Edited by Ivan S, 14 July 2014 - 01:09 AM.

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#13 Nerf Gra

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Posted 14 July 2014 - 06:50 AM

It's comfortable for me, but if you want more hand room you can make the stub between the tee and cap longer. Fill it with hot glue if you're worried about dead space.


Twist fittings aren't safer, but they are better for noobs because they aren't permanent. For example, if you pvc cement your OPRV subsystem to the tank only to find out that it leaks, then the whole assembly becomes useless. But with twist fittings, you can just replace the bad subsystem with a working one.


Thanks that actually helps a lot I was worried about it being supper awkward but that doesn't look too bad.


Threaded fittings also happen to make it modular. For example.
You could make 3 different oprv pieces to make it tuneable for more power.
You can have multiple blasters with slightly different sized tank volumes.
You can have different ammo type/size assemblies.
And you could use the same trigger and pump assembly for every combination of parts.
That is actually my favorite part about this blaster.
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QUOTE(VelveetaAvenger @ Dec 6 2010, 12:14 AM) View Post

Maybe there's no Mcmaster, but you could make the first coconut airtank.




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