I plan to make a working Tetrap net launcher with air power, using this air powered potato gun as a start to the design.


Working out how big the prop is hard enough, but making it & putting it together is even more difficult.

I started off with 2" PVC for the rings on the main tube, the main tube being 1 1/2".



I couldn't find any PVC parts to bridge the small gap between the 1 1/2 & 2" pipes, so I cut slivers of a thin wall 4" drain pipe to fill the gap.



I took a level cardboard template to cut the right size of PVC to fit in the section pieces of 2" pipe. Then I heat them up & glued them into place.



BUT! The thin wall pipe is still too thick to insert the 1 1/2" pipe, SO, I'm going to have to go threw all my pipes on my drill lathe & softly grind them down with my drimel. If I'm not careful, I'm going to have to tare or grind out the spacers & cut more to try again.

Great start! Your one will be considerably more authentic than my one. I wish I had the patience to spin plastic tubing to do it but alas, I took the easy way out :-D

Quote from: davidnagel on Mar 09, 2023, 12:15 pmGreat start! Your one will be considerably more authentic than my one. I wish I had the patience to spin plastic tubing to do it but alas, I took the easy way out :-D

For me 3D printing isn't easy. You have to draw out accurately sizes diagrams with a complex & confusing software, convert the image into a file for your printer to understand, set up your printer with it's overly sensitive settings, aliening the nozzle, temperature settings, distance from the printing platform, cooling speed, then theirs removing the little rods that hold the print up, & finally sand & glue the prop together.
Compared to me, YOU, are a GENIUS.

Just wanted to let you know, I'm having trouble making time to do more of this project, manly because of my mother's day to day routine. She has bin forgetting things lately, she has to be watch every minute.

But I like to share with you a diagram of how my air Tetrap gun will work, to keep interest going for this topic.

Fill air from the back threw the one way valve, it pushes the silicon plunger against the out flow pipe. Meanwhile it leaks around the plunger filling up the sealed outer pipe around it, aka the air tank. Pull the valve trigger on the handle & it lets al little air out pulling the plunger back, letting out all the air in the air tank. 

The 2" coupler is for the peace's on the end barrel which are larger than the 2", that comes later. The Coupler tab has to be ground down to slide the entire coupler on the 2" pipe.



The back end needed a coupler peace too, along with a dremeled down disk to plug the end of the pipe & add an air line, aka the hole in the center of the disk.The coupler had to be cut down to fit the size of the prop & the center lip left intact for the disk plug.



Now for the side pipes on the tip of the gun. 1/2" SCH 40 & 11 size fits perfectly, with a little brute force to slid them in. Marking out the cut lines, cut & finished with this part.



I tried making the inner piston pug for the air gun part. I did it all wrong. I got the wrong type of silicon, I didn't know I had to emerge the silicon in soapy water & need it instead of just applying a generous coat to the pipe mold, & I didn't now it was going to stick to the cocking sheet I put underneath it.
I glued the pipe to the cocking sheet & once it was firmly solidified, I had to tear every little pace off of the silicon touching the cocking sheet.

After I was done with all of that, I had to replace the bolt holding my drill lathe chuck to my drill because it was off center. The bolt on the chuck is not a standard bolt & had to go threw the process of taping the bot hole on the chuck & somehow lathe the bolt to fit in the drill chuck.
Put it simply, I had to put allot of work in my drill lathe & got it fixed. Eventually.

Quote from: elkad on May 09, 2023, 10:44 pm

Now this is what I wanted to do but couldn't find it in me, this looks lovely!

I finally got a little time to do some work on this prop.
Drawing out the stencils out of poster board for stability, then stenciling on to 4" PVC irrigation pipe.



I don't know how I'm going to attach this, but I'm trying to fit a air compressor blow gun valve to let out the air & launch the confetti.

Making a one way air compressor valve, which can work as a trigger if, I can't get my handle trigger set up & working.
Its made of an air compressor connector, mip connector, cap, nail & a notepad binder spring.



I'm using a square gasket I bought at Lowes for the gasket on the nail. I drilled a hole in the gasket, stuck the nail in, cut off the excess, & ground down to fit.



I marked down the end of the nail were it pokes out the tip of the air connector, leaving just enough to press it like an air release. The pic's are just me having fun trying to catch a random spark from dremeling the nail



I drilled a hole in the cap to let the air out. I know I should have just go a compression nut for this so I wouldn't have to drill the hole, but I didn't think of it at the time.

I just got the tubing for the air gun & even with angle peaces, it wont fit in the handle aria, (I'll get pics later), so I bought a 6v solenoid valve.

It just wont look right with a tube sticking out the top, so I'm going for something smaller. This dose mean I'll need a 6v battery pack or one of those rechargeable lipo battery.

I used a hole saw to cut a 4" disk, but I didn't have a saw blade for a 2" pipe hole, so I cut it with a 1 1/2" & Dremeled the rest to fit. With a combination stencil, which I should have used first to get the hole close as possible when grinding.



I cut a slot in the side emitters to fit on the barrel disk. I plain to drill a hole in the disk to fit the copper pipe in & lock the emitter in place like a, well, locking pin.



I'm also changing the cap end where the air go's in so I can unscrew the cap to get at the plunger valve. I expect everything to go wrong, so I'm taking no chances with a permanently glued together pipe.



I needed tabs to stretch out the disk to fit in the pipes. Not, an, easy, job. I need to cut a slit in the disk so the tabs will fit. Measuring & slowly grinding down the tab to fit in the tube. Along with a starter drill hole until I get all my piping together. I need more copper tube.



A quick preview look at the barrel tip, without all the other rings on it, & the side emitters.

The tip with it's rings.



I put a half a plastic hemisphere on the 2" pip & pushed the 1 1/2" pipe against the sphere & marked off where it touched. I then cut a large enough hole to get my Dremel threw & ground down to the line, slowly little by little til the 1 1/2" pipe pops threw. Then I glued it.



I still got a long way to go. I still need to make the spacers for the inner pipe & drill holes or gaps to accommodate the air tubes below the barrel. Along with making the handles & wiring up the 6v air release valve.

On top of that, I have being going threw a nasty cold for the past two days, Hacking & Sneezing. It hasn't bin fun feeling like hot needles are attacking my throat every time I cough. 

Now I measure out a strip for the handle & use my heat-gun to fold the PVC in the shape of the handle. It's not easy without a wood mold to cool on. This is all held in place with gloved hands. (VERY HOT PLASTIC)



I cut a hole in the side for the trigger switch I glued a mounting panel on top, also cutting a hole in it to accommodate the electric contacts from the trigger switch.



Now the handle top. I tried just folding a single piece but it was to difficult to hold the limp plastic when I went to heat another section & it unfolded on me. So I started with the line up & down sections, just having to cut little pieces off at a time, then, the oval pars with the heat-gun, using the edge of the panel as a mold guide before gluing it to the panel itself.



I marked & cut out the handle tab points & drilled mounting points for the handle panel. Inside is a few mounting points inside with blocks op cut PVC.



Now connect the two parts, lining up the slats & tabs. (Tab A Go's Into Slot B)



Because of the mounting blocks on the top part of the handle I had to cut gaps in the fins on the top, not only to fit, but makes a good guide to align the screw holes.



The trigger switch wasn't align properly & need to go back over it with some extra PVC to make a straight hole for the mounting holes & switch.