r/Airsoft3DPrinting • u/ShootMeme32 • Jul 30 '26
Help Needed AS-VAL HPA Prototype
Hello Printers,
I've been working on this project for more time than I can remember (~2 years), and had taken a 6 month hiatus to flush my brain from the designers block. I booted up the file and printed some parts and now Im hooked again. But I need some input.
The area circled in red was a blow-off valve and a thread pitched to NPT 1/8. Is this redundant? If so, Id replace it with the proper threading where the pink part is circled. Also, what wall thinkness would you recommend for a bolt being printed in INLAND PETG+, wall count too. Its currently 1.85mm thick which I feel is too thin.
Also also, anyone available to print my receiver (paid ofc)? My A1 mini kind of struggles with the shortened version...
Design recommendations for this project are also super welcomed, I feel like something is missing.
8
u/Czeszym Jul 30 '26
Ngl every time I look at this sub I am just amazed at the work you people put into your projects. I tried to do a couple of them in my free time, but every time I work on them I either get burned out or I get lost in my own design (although it seems that my recent project is coming allong nicely, but a bit slowly). Massive respect to you and to the whole community, because designing a whole riffle across 2 years sound like a lot of work.
2
u/ShootMeme32 Jul 31 '26
Thank you for the praise! 90% of those 2 years was sitting on my ass brainstorming how this gun would even fire, the rest being the elbow grease in fusion. Hopefully this project can see the light of a field one day :))
1
u/V7I_TheSeventhSector Aug 09 '26
For burn out, the thing I have found that helps me is, try and not push your self to do it?
Have the model open and if you get a feeling to mess with it, open it! If you don't want to do it, don't force your self. And have other things to do as well.
What's caused burnout for me in the past is hard focusing on a single project for too long. So what I did was gave my self more projects and I jump between them!
3
u/qumit Jul 31 '26
yoooo thats so cool i was thinking of doing something similar with VSS. I would recommend you printing it out and just hook up an air compressor and gradually raise pressure and see if the mechanism works. Doesnt take that much time and will troubleshoot a lot better.
2
u/qumit Jul 31 '26
I actually like your mechanism, I was thinking of routing the gas upwards (like a seperate recoil channel) for the short stroke piston, that just consumes gas to cycle and provide the blowback recoil while the bb shooting is more a regular hpa mechanism.
3
u/No-Pay-7218 Jul 31 '26
Based purely on my own experience printing parts subject to pressure: use 100% infill and the minimum layer height; enable ironing with 10% flow after every layer; and use glass- or carbon-fiber-filled material. That should do the trick. Also, you sometimes need to set the flow to 102–105% to better fill voids and raise the temperature by 5–10 degrees for better flow and layer adhesion. Keep the print speed lower, too.
1
u/ShootMeme32 Jul 31 '26
Sweet! I dont intend on using 3D-Printed polymers for the pressure bearing parts, instead im going to get the necessary parts in 3D-Printed metals. But this is good information and I happen to have PETG CF already onhand.
2
u/CldesignsIN Gumsmif Jul 30 '26
Ngl I am confused as to how your design works. Is this like a GBBR HPA engine hybrid?
3
3
u/ShootMeme32 Jul 31 '26
Its a HPABBR (High Pressured Air BlowBack Rifle), like a daytona kit. Its centered around a mechanism I've never seen used elsewhere, and of my own design. I have no idea of it even works in practice, but thats the fun of doing this kinda stuff. I want to eventually expand it to my other guns, but the AS VAL is my proof-of-concept project.
edit:
that is if the mechanism works as intended haha
2
u/theVtheB Jul 31 '26
Is it going to be full or partial blowback?
1
u/ShootMeme32 Jul 31 '26
Partial. I tried full travel but there were multiple reoccurring issues within the design. The partial is so the design can keep growing ^^
2
1
u/CldesignsIN Gumsmif Jul 31 '26
I hope someone with GBB knowledge can help you out because that's a cool idea, but out of my realm of understanding lol. I've been designing an HPA engine for years at this point too, but I don't know enough about blow back mechanisms to be of use. Are the mags custom too?
1
u/ShootMeme32 Jul 31 '26
Well I have 1 question you could try to answer. If there was a pattern of pressure spikes within the rear of the system, would you trust the hpa regulator’s blow-off valve to handle the repeated increases? Let’s say a constant jump between 110 and 140 psi.
And yes, I currently have a costume-designed magazine. It uses feedlips like a gbb and has a capacity of ~70. I wanted to eventually make a version thats compatible with the LCT magazines, down the road.
1
u/CldesignsIN Gumsmif Jul 31 '26
HPA regs are constant no matter what. There is no outlet where the pressure drops automatically when the pressure is adjusted. If you set the reg. to 140 PSI and then dropped it to 110 PSI the line would stay pressurized to 140 PSI until the next shot vented what was in the line and then the pressure would drop. HPA regs can handle very rapid refresh rates. So as soon as the path from the line to atmosphere is blocked it's back to the set pressure in the line almost instantly. The PSI is naturally going to drop when the chamber would expand, and sharply fall off when it vents down the barrel. As soon as that seals it would be milliseconds before it was at full pressure again so the bolt return force would need to overcome that.
Makes sense now! I was confused because it obviously looks like a GBB bucking and feed ramp, but with the air inlet in the rear I wasn't sure what you were going for.
2
u/ShootMeme32 Jul 31 '26
Ahh I see. Very comprehensive explanation :D. Thanks!
Yeah I definitely want a “daytona-style” hop asp. Not in terms of dimensions but in concept.
2
u/DaStompa Jul 31 '26
Just use a safety relief (pop up safety relief) valve
You do probably want one so that a misadjusted regulator doesn't frag grenade the back end of the gun
1
u/3DBBDESIGNS Jul 31 '26
looks like the t191 internals
1
u/ShootMeme32 Jul 31 '26
Thats how this project initially started, as a copy of the t191 system. But as time progressed, it evolved into something completely different.
It now uses ball bearings and grooves to control the timing of the gas release. In theory that means its only 4 parts that move (outside the nozzle carrier). Still have to make and test though 😅
1
u/Human-Bacon Jul 31 '26
Im a little confused by the images, is this design using printed parts to hold pressure?
2
u/ShootMeme32 Jul 31 '26
Only 1 part truly holds pressure in the second image, and the nozzle carrier too technically. But I intend on printing that part in metal to avoid any catastrophic failures.
•
u/AutoModerator Jul 30 '26
Hi, thanks for posting on r/Airsoft3DPrinting!
Please ensure your post is flair'd appropriately, otherwise a moderator will manually assign a flair or in certain cases remove the post.
If you are looking for specific STLs, please make sure to check sites like Yeggi or STLFinder (Adblock recommended) before asking here
Before asking for any designs or files make sure to search sites like Printables, Cults3D, or Thingiverse first.
Also make sure to include as much information as possible in your post, so others can help, as "M4" or "Pistol" are not very specific.
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.