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Check Valve/O-ring Plunger Head

3D Printed Version
homemade 3D printing parts

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#1 Ryan201821

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Posted 05 June 2014 - 03:04 PM

Background:

About a month back, Kane realized we could use the same concept T da B used in his Ported Piston Plunger Head, and create a version that was 3d printed.

Kane then made a version for the Aabow, and it worked very well.

VUrqIBo.jpg

Revolutionizing Plunger Heads

I used almost the exact same thing for the ESLT Blasters.

esltphcollage.jpg

I guess it works slightly different than T da B's, since it relies on the o-ring sealing against the back of the plunger head, instead of covering the holes for it to seal. While it's priming, the o-ring slides to the front of the plunger head, allowing air to pass from the front, to the rear, through the super air channels, bypassing the seal. In this 3d model, you can see the invisible air channels that accomplish this.

plungerheadinternalview.jpg

When the blaster is fired, the o-ring seals against the back of the plunger head, making the holes for the check valve irrelevant, since they're in front of the seal, and the o-ring seals against the back of the plunger head.

These work phenomenally well, and will be used on our blasters whenever possible. As far as I can tell, this gets as good of a seal as anything, and is a hundred times less expensive than a skirt seal. Total cost for one plunger head is less than a dollar including the printed parts and the hardware required for it to work.

Forward-Style Plunger Head

Since most people (p much e'rybody) don't build bullpups, or ESLT style blasters, we figured there would be more of use to everyone else if we made something for most traditional homemades.

pbphcollage.jpg

These are yet to be tested, but work exactly the same as Kane's earlier version, and the current ESLT version. The plunger head is mounted with one #6-32 x 3/4" Flathead screw, which requires a hole in the end of the plunger rod. I designed this one in particular for 1/2" plunger rods, since that seems to be most common. I would do a version to accept 5/8" diameter PRs, but this design won't allow for it with the tolerances needed for the air channels. There is definitely a way to do it differently, and I'll eventually explore this.

========================

Conclusions:

I don't really see any disadvantages to this design, if you have a 3D printer obviously. If you'd like to pad your plunger head (which you should) from slamming into whatever it slams into, just glue/affix/leave a piece of rubber wherever your plunger head hits. If you add padding directly to the plunger head, you'll cover up the check-valve holes, and the whole plunger head will fail at it's purpose. For the ESLTs, I've been using rubber washers that just get wedged inside the plunger tube and rest on the redirect piece.

These so far seem as durable as anything else I've used for plunger heads, but time will tell. We've been using 3d printed plunger heads for over a year now, and haven't seen any problems with them degrading over time. These aren't really too much different from the normal ones we used to print, and in fact are stronger because we decided they might as well be printed with solid infill.

If you want to be one of the cool people who would like to acquire one, they are available pretty cheap on our Sales Thread.

If you want to be cooler and just print it on your printer, here are the files.

File Downloads

Download Stp Files Here

Parts List
ESLT Style
9452K36
90273A151 x2

Forward Style
9452K36
90273A151 x3


Edited by Aeromech, 23 November 2015 - 03:03 AM.

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#2 Drev

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Posted 05 June 2014 - 04:09 PM

I can provide some step files if people are interested, as well as a version for pullback-style blasters.

I'd be interested in both of the files.
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#3 Ryan201821

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Posted 05 June 2014 - 05:25 PM

ESLT Version - Assembly
ESLT Version - Front Piece
ESLT Version - Back Piece

Pullback Version - Assembly
Pullback Version - Front Piece
Pullback Version - Back Piece

To download, right click and "Save link as". Save as an ".stp" file and you should be able to view it in your preferred modeling software.

Updated to first post.
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#4 BuffNerd

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Posted 05 June 2014 - 07:25 PM

What is the durrability of the plunger head like? I don't have too much experience with 3d printing, but I have used some of Kronos's printed wyes and they do break on occasion with stress on the printing lines. I would figure that with the constant abuse of slamming into the front of the plunger tube could result with damage even without dry firing the blaster. But other than that, this looks great and I'm very interested in using this in the future. It might useful to attempt resizing it to much larger plunger tubes, the 2-11 comes to mind.

Edited by BuffNerd, 05 June 2014 - 07:26 PM.

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#5 Ryan201821

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Posted 05 June 2014 - 08:02 PM

What is the durrability of the plunger head like? I don't have too much experience with 3d printing, but I have used some of Kronos's printed wyes and they do break on occasion with stress on the printing lines. I would figure that with the constant abuse of slamming into the front of the plunger tube could result with damage even without dry firing the blaster. But other than that, this looks great and I'm very interested in using this in the future. It might useful to attempt resizing it to much larger plunger tubes, the 2-11 comes to mind.

Forgot to comment about that. I've been using a pad for my plunger heads to slam into, and it seems to hold up no problem. Another huge factor is these are printed with a 0.6mm nozzle which is a lot larger than traditional hot ends use. This means the perimeters are much thicker and stronger. I also do these in solid infill, which basically makes them invincible.

As far as resizing it for other plunger tubes, it would be really easy. That's the beauty of 3d printing.

Edited by Ryan201821, 09 June 2014 - 02:00 PM.

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#6 Thorn

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Posted 05 June 2014 - 10:17 PM

Will you be using this on all of your guns? Are there any guns that would not benefit any more from this then say a U-cup? The fact that this eliminates the need for an external check valve is a huge plus. This looks great, and I'll probably buy one when you start selling them.
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#7 Ryan201821

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Posted 06 June 2014 - 05:12 AM

We will most likely be using these for at least the Aabows, ESLTs, and a future pullback blaster in the works,

I see no advantage to using a u-cup over this. These are six cents each and a u-cup is about a dollar.

Not sure what we will sell these for but they'll be cheap and probably the first printed piece we will have for sale.
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#8 Drev

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Posted 10 June 2014 - 06:18 PM

What are the specifications of the o-rings that you are using on these? Would 9452K79 be appropriate?
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#9 Ryan201821

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Posted 14 June 2014 - 10:08 PM

What are the specifications of the o-rings that you are using on these? Would 9452K79 be appropriate?

That part # would not work. You need to get, 9452K36

Tomorrow I'll update the first post with some new relevant information.
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#10 KaneTheMediocre

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Posted 16 June 2014 - 05:36 PM

As far as resizing it for other plunger tubes, it would be really easy. That's the beauty of 3d printing.


Note that resizing the printed parts for other plunger tubes is trivial and easy, but sizing the o-rings is not trivial and easy. Since these hold the o-ring loosely by necessity, you must find an o-ring that actually fits the plunger tube--stretching the o-ring isn't an option. Given the wide variety of o-rings available at McMaster or even Ace Hardware, this is no problem for any reasonable size. Of course PVC is not made to reasonable sizes, so being able to do this in 1 1/4" PVC pipe is a lucky dimensional coincidence. Other PVC sizes will be more difficult to match to O-rings, but tubes with not-ridiculous inner diameters will be easy.
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#11 Ryan201821

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Posted 17 June 2014 - 02:47 AM

stuff

These are good points, thanks for filling that in.

I've updated the first post with some relevant information and added the McMaster #s.
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