Saturday, August 20, 2011

SGN-8T : Modular PVC Turret Design - Build Guide!

This was a side project that i worked on back in 2010, i completed almost 90% of it, but ended up shelving the parts 'cos i shifted my focus onto other modding projects.

Recently, i've been modding a few blasters which came in single barrel designs, they have great performance but with all the new blasters available nowadays with much higher ammo capacity and RoF, single barrel blasters tend to be at a slight disadvantage in Nerf games, so i resumed working on modular PVC turret designs to further improve the effectiveness of those single barrel blasters.

Some modders may have also seen the excellent 8-shot turrets made by SorrowX at the NerfHaven forum, he used a 3D printer to create his turret parts and the result is nicely made parts... though unfortunately the parts creation process itself is largely inaccessible to most of us modders.

My modular turret design aims to achieve a similar goal, except that it does not require a 3D printer, just PVC pipes and epoxy glue. :)

Here is the process...

Step 1:

These are the basic materials and tools that you'll need.

- 13mm / 16mm / 20mm SingaPlastics PVC Pipes (Thinwall Versions)
- 1/2" PETG Tubes (.528" ID / .572" OD)
- 2-Part Epoxy Glue (I use Selleys Super Strong Epoxy Glue)
- Pipe Cutter

Note that all the pipes and tubes i use are able to nest within each other. This turret design is built around those material specifications.

Its also possible to make this turret with non-nesting pipes and tubes too, you'll just have to adapt the parts to fit and align with each other.

Step 2:

We will start with the barrel spacers first.

For each barrel spacer, cut 8 x 1cm length 13mm PVC pipe and 1 x 1cm length 20mm PVC pipe. Ensure that the cuts are even and matching, avoid making angled or uneven cuts.

Use the pipe cutter's reaming tool or a hobby knife to trim off any sharp bits sticking out, so that the barrel spacer ports have a smooth surface.

Position the smaller pipe rings in a balanced circle around the central large pipe ring, then fill the space in between with epoxy glue. Constantly make sure that the parts are all aligned properly.

I did the gluing process in stages. The glue is applied in successive layers, each time the glue is properly cured for a few hours before the next layer is applied. After 3-4 layers, the space will be filled in nicely and forms a very tough bond between the parts.

Do this twice to create 2 x barrel spacers.

Step 3:

Next will be the PETG barrel assembly.

In my example, i use 1ft length barrels.

Cut 8 x 1ft PETG tubes and slot them into the barrel spacers, check that they are all aligned.

Do NOT glue the barrels in yet! We still need to mount the barrels onto the main turret assembly later.

Step 4:

This is the main component of the turret system, which comprises of the connection and turret rotation points.

Cut 1 x 4.5cm length 16mm PVC pipe, 1 x 2cm length 20mm PVC pipe and 1 x 2cm length 16mm PVC pipe.

Epoxy glue them together vertically, make sure they are aligned with the barrel spacer positions.

Step 5:

Build up the rest of the turret fitment parts.

Note that i design my turret connection point to connect to 20mm pipe couplers which i use in all my modded blasters, if you use other kinds of couplers, you'll have to adjust accordingly.

Cut 1 x 2cm length 20mm PVC pipe (as the connection point), 1 x 4.5cm length 13mm PVC pipe (to slot into the main nozzle to reduce deadspace), 1 x 5cm length 16mm PVC pipe (as the barrel spacer holder and rotation point) and 1 x 1cm length 13mm PVC pipe (as a base for the bottom turret "barrel stopper", explained later).

Epoxy glue everything in.

Step 6:

Prepare the turret system.

Cut out a suitable sized ring of foam padding and attach it on the top nozzle for the turret seal, put a rubber o-ring around the middle rotation point (i used a Nerf Stampede o-ring, apply grease to it so that the rotation is smooth) and stack some foam inside the bottom section along with a dome shaped stopper (i used a plastic button from a coat).

The dome shaped part at the bottom acts as a "barrel stopper", when the turret turns, the stopper will be pushed back and compress the foam behind, then when the next barrel is in position, the stopper pops back forward and locks the barrel in place.

My earlier designs used a toothed clutch system, but i found that too troublesome to make (alot of tedious precision cutting of the PVC sections needed), and they were not really required since there isn't an integrated auto-rotation mechanism anyways.... the system just required something simple to hold the barrels in place.

Step 7:

Connect the turret system to the barrel assembly.

I used 1 x 1cm length 16mm PVC pipe as a fastening collar to secure both components together, bolted on with 2 x machine screws. This also facilitates easy changing of parts if required.

The fit of the fastening collar is very important, make sure it secures the parts tightly (but still allowing smooth rotation with the o-ring), this keeps the barrel assembly constantly level with the air exit nozzle at the top section. This is essential to achieve 100% turret air-seal.

The barrels can now be glued in permanently if you wish... but in my case i leave them secured by friction fit, i've test fired hundreds of shots and they all still stay in position (just adding an extra layer of tape on the looser barrels did the trick), so i can also have the option to change the barrels anytime if needed.

Every barrel has been tested with 100% turret air-seal, the plunger stops mid-way when the barrel is blocked and it can even vacuum load foam darts too. :)

Completed SGN-8T : Modular PVC Turret!

Here is an example of the Modular PVC Turret fitted on a modded PAS with a 20mm coupler connection... i call it PAS-8T.

Rear loading ammo slots, 3 on each side = 6 rear loading slots in total.

The turret can be easily swapped between blasters with compatible coupler connections. :)

Demo Video!



  1. Ahhh, the turret has the same rotating design as a tek 3

  2. Hey SG,

    Can you get me the specifications for the

  3. soloz1,

    The o-ring i used is approx. 25mm OD / 21mm ID.

  4. Can you get me the english measurements to do this? Also I am not geting how you attach the back part to the barrels. Where did you put the screws?

  5. Also, where did you get that foam(mha?)? The tips don't look like traditiional dome or slugs(duh!). Could they be shmees gumdrop heads?

  6. Isaac Zeh,

    English measurements? Most of the measurements i post are already in metric... and for the inch figures, just convert them to metric for reference.

    The fastening collar is secured with machine screws installed into the sides of the collar, you can see the head of one of the machine screws in the close-up photo of the fastening collar (look in between the PETG tubes).

  7. soloz1,

    The red foam i use are custom made hollow foam rods and the tips are custom made and weighted silicone rubber tips. They were sourced from inf0rm3r at the OzNerf forum.

  8. babydragon1236,

    The blaster shown in my turret fitment example is a modded version of the ERTL Pump Action Shotgun (aka PAS).

    You can read my review of the stock version of it here:

  9. Do you get the thin-walled UPVC from Poh Hong hardware as well?

  10. do the blasters you put them on get better ranges?

  11. AD MAN,

    Well, for my turret design, the ranges are the same as if a single 1ft length PETG barrel was used... the difference is that it enables the blaster to fire more shots before requiring ammo to be reloaded (and also allows for quicker and easier rear loading of ammo too).

  12. What type/kind of foam padding did you use

  13. attackthekid,

    I use soft foam padding that are designed as bumper material to protect household furniture, similiar in density and texture to craft foam.

  14. Isn't this supposed to go in DIY blasters? And also, what happened to DIY blasters?

  15. qazwsxedcrfvtgbyhnujmikolp,

    Well, the turret is designed to fit on existing blasters, so i categorize it under blaster mods. :)

    You can still find the DIY Blaster site at its original URL:

  16. hey sg, would this work with a titan thats been couplered, as i want to build this, the coupler size is 25 mm

  17. Shaun2233,

    Possible, this design can be adapted to any coupler size, just build it using a matching connector point.

  18. Sorry for having to ask, but what are the ID/OD measurements for the PVC you used? I'm trying to order supplies online and I don't want to buy the wrong thing.

  19. TheWiredDJ,

    For the SingaPlastics brand PVC pipes that i use, here is a link to the manufacturer specs:

    Note that there can be variations in the PVC pipe dimensions (even within the same length of pipe), so i'd usually recommend users to physically test out each batch from the suppliers to make sure they can fit and nest properly within each other.

  20. Just one last question, on the link you gave me, the 13mm PVC converts to 3/8", and yet it sleeves over 1/2" PETG?

  21. Nevermind my last post, I didn't analyze what exactly the chart on the website was saying.

  22. TheWiredDJ,

    Yeah, thats the thing with PVC pipes, their parts labels don't usually reflect their actual dimensions. :)

  23. Well thought I would throw this out there for everyone: uPVC isn't available in the US. And it costs upwards of a few hundred dollars to order some from overseas.

  24. TheWiredDJ,

    Yup, it's better to just use similar pipes and parts that you can source locally, no need to go through all the extra expense to import such materials. :)

  25. what are the ID and OD of the petg?where can you find that specific dimension of petg?and do you need to request to the shop person for that kind of petg?thanks

    1. somebody,

      As already mentioned in the guide, the PETG tubes dimensions are .528" ID and .572" OD.

      Those PETG tubes are one of the most popular barrel materials used for Nerf mods, you can usually get them from other Nerf modders who have them for sale on Nerf forums.

      Most hardware shops would not have that exact PETG tube dimensions though, it is a very specific material.

      If you are in Singapore, you can get them directly from hanzo at the NerfSG forum, he usually has spare stock of those PETG tubes.

  26. Hi SGN, Do you have a writeup for the pas's stock mod?

    1. Anonymous,

      You can check out how its done in my shoulder stock modding guide for the modified ERTL Rapid Fire Shotgun (aka Doomsayer):