Improved Throwline Cannons (Better than APTA)

sinthome said:
and tampering with it is "at your own risk".
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If your going to sell these without speaking with a lawyer first, I think I would change this line to "use at your own risk". Not because I think there is a design flaw, but because you just never know what can happen, or how someone else may treat their tools. Each time it gets tossed on the ground or in the truck could remove some of the cycles to failure. When pressurized air goes bad, there's potential for it to go really bad.

Btw, I have built 2 similar tools myself. One with a valve that used a push button trigger requiring 3-9 volt batteries to power the actuator. So I'm all for it, just make sure to cover yourself.
 
Pile can still shoot themselves in the face bring dum and or drunk.


Autocorrect on a phone, in a hurry, without proofreading, probably.

They can still shoot themselves in the face being 'dum' and/or drunk, or stoned.
 
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sinthome said:
Hi folks, I'm excited there seems to be a lot of interest. I plan on making a video next weekend. Not to drag out the suspense, I'm just busy until then!

An HDPE pressure chamber is a good idea, but it would probably have to be custom made. I've not come across HDPE pipe and fittings or a small tank that is rigid enough to work effectively.

The launcher I am using is made entirely from pipe and fittings rated to a safe working pressure (at normal temperatures) of at least 200psi. Burst pressure is much higher than that, obviously, but any launchers for sale will still include a pressure gauge and safety pop valve that opens at 150psi and tampering with it is "at your own risk". Additionally, in the unlikely event the chamber was ever overinflated to failure, there is a rubber gasket in the main pressure valve that would tear long before the metal would burst.

A better safety comparison would be paintballers, who run around with co2 and hpa tanks of an equivalent volume and that are often holding thousands of psi pressure. TBH this terrifies me, but also makes me respect the strength of metal.

Lightweight aluminum pressure tanks, if they can be safely modified and sized properly for the application, make for an ideal launcher chamber and have been used successfully for tshirt launchers, etc. If I tinker around with a different chamber, it'd be using an HPA tank.
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You may want to consult a local commercial plumbing contractor, at least take a look at HDPE it is brutally strong! Your components could simply be glued together, reducing manufacturing cost by a mile!
 
IMHO the strongest material isn't the way to make it safe(er). The better way is to use materials properly rated for the pressure, and stay below that pressure by design. Anything can be over pressurized. Some fool will hook it to a nitrogen supply or some other unacceptably high pressure vessel. There is a huge world wide industry that uses metal storage for compressed gasses. Unless HDPE is both cheaper and easier to work with, I'd skip it for a limited production run.

However, I would add a design feature that functions to limit overall pressure. The compressed air tanks you buy at a supply house all have relief valves that blow off above the intended use pressure but below the full rated pressure. These valves are designed for flow, so they are rated so they will blow off faster than the fill mechanism will allow the device to be filled. It takes a pretty small valve to blow off more than an automotive type schrader valve can fill. The final user would have to tamper and modify the device to defeat the safety. They also cost under $10.

In short, don't overbuild it. Instead, add an automatic safety device for the most likely dangerous misuse.
 
adaycj said:
IMHO the strongest material isn't the way to make it safe(er). The better way is to use materials properly rated for the pressure, and stay below that pressure by design. Anything can be over pressurized. Some fool will hook it to a nitrogen supply or some other unacceptably high pressure vessel. There is a huge world wide industry that uses metal storage for compressed gasses. Unless HDPE is both cheaper and easier to work with, I'd skip it for a limited production run.

However, I would add a design feature that functions to limit overall pressure. The compressed air tanks you buy at a supply house all have relief valves that blow off above the intended use pressure but below the full rated pressure. These valves are designed for flow, so they are rated so they will blow off faster than the fill mechanism will allow the device to be filled. It takes a pretty small valve to blow off more than an automotive type schrader valve can fill. The final user would have to tamper and modify the device to defeat the safety. They also cost under $10.

In short, don't overbuild it. Instead, add an automatic safety device for the most likely dangerous misuse.
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HDPE was a suggestion, it handles pressure very well, does not require welding. Pressure vessels require rating either way you go. This device won’t be legal to sell without one.
 
Stephen Moore said:
HDPE was a suggestion, it handles pressure very well, does not require welding. Pressure vessels require rating either way you go. This device won’t be legal to sell without one.
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I'm sure HDPE is fine if properly executed. But using it simply because it is "stronger" isn't the entire solution. That was my point.

The legality varies by state, and intended market. ASME ratings are also a complicated beast. There isn't a blanket "it's illegal vs legal" in these cases.

I hope the product turns out to be safe and useful. I don't envy entering this type of market. These conversations are always useful because they are a reminder that certain projects require caution. Ones with pressure vessels are an example.
 
Just to clarify, I am not doing any welding on the aluminum pipe. It is Schedule 40 rated pipe with threads. I think this is also the case for the APTA, which makes it easy for anyone with basic plumbing knowledge to repair, modify, rebuild, etc. It is a good way to go. Imo, pipe weldng is great for steel but kinda a pita for aluminum.. although I'd prefer either to huffing pvc pipe cement fumes.
 
sinthome said:
Just to clarify, I am not doing any welding on the aluminum pipe. It is Schedule 40 rated pipe with threads. I think this is also the case for the APTA, which makes it easy for anyone with basic plumbing knowledge to repair, modify, rebuild, etc. It is a good way to go. Imo, pipe weldng is great for steel but kinda a pita for aluminum.. although I'd prefer either to huffing pvc pipe cement fumes.
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That may be more of a problem? Modification of a pressure vessel might not be preferable in their eyes?
I like your idea, I’m not a huge fan of rubber bands either. I hope this works out for you, the major stumbling block will be certification particularly for sale in other countries and maybe even other states?
I was contemplating making a similar thing myself, I think many of us have had the same thought.
 
The weekend got rained out, lol. Here's a photo of my 1-1/2" valve version. In the photo, I was messing with some stuff and took off the trigger mount, but this is basically what it looks like. I get 90ft on 60psi or 12 pumps of a bicycle floor pump. I also have a version with a 1" valve which is actually more work to build and not really cheaper, but the valves are sometimes easier to find. The concept is pretty straightforward, but for anyone that needs more convincing I'll make a video when things dry out in this here rainforest.

I'm not trying to get certified to commercially sell anything let alone internationally, lol. I think this thread went pretty far beyond what I intended and I have no particular delusions of grandeur when it comes to building a better potato gun thing.. but this design is still the best way of getting a line set in a tree, imo.
 

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sinthome said:
The weekend got rained out, lol. Here's a photo of my 1-1/2" valve version. In the photo, I was messing with some stuff and took off the trigger mount, but this is basically what it looks like. I get 90ft on 60psi or 12 pumps of a bicycle floor pump. I also have a version with a 1" valve which is actually more work to build and not really cheaper, but the valves are sometimes easier to find. The concept is pretty straightforward, but for anyone that needs more convincing I'll make a video when things dry out in this here rainforest.

I'm not trying to get certified to commercially sell anything let alone internationally, lol. I think this thread went pretty far beyond what I intended and I have no particular delusions of grandeur when it comes to building a better potato gun thing.. but this design is still the best way of getting a line set in a tree, imo.
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Well ok then , in that case when you get er dialed in I'll take one!
 
39Buick said:
Lol, somehow I can see you running out to the shop and engineering one of these the “Stu” way! Just popped into my head when I read your comment! Had to laugh!
Let us know how it turns out! :sisi::sisi::sisi:
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Ah, am I that predictable? LOL. I was actually just working on a mapp gas fired version last night! I saw some youTubes of a propane fired golf ball launcher and also potatoe cannons. Of course it was obvious one of these could be adapted to fired throw bags. I started making one out of copper instead of the weaker PVC. It might end up being rather heavy so would not be convenient on a long hike through the woods, but as long as one can park not too far from the tree I think it might prove useful. My daughter says it will look quite steampunk, whatever that means. Anyway, will get some photos and video of it when it is ready for testing.
 
Hey y'all sorry playing catch-up after all the rain. I'll get a video up this next weekend. Burrapeg, there are several options you can pm me and I'll give you the details on all the best valves.
 
Personally, love the idea and have been at it myself as well as I could see spending 200 for a APTA even if they were in stock. That being said, it looks like the folks at J&J sporting goods in Marietta Ohio have it figured out
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Update, I called JJ Paintball today to inquire, and not only was Frank Casto happy to share the information with me, he also mentioned that he has built the exact cannon we are all seeking, for the United States Forest Service for measuring Sequoia's. You can find him on Facebook at Frank Casto or JJ Paintball. I have no affiliation, I am just stoked to hopefully have solved this problem permanently. As even he said we dont need polished aluminum barrels, get the can and trigger assembly from him and add your own barrel. I still am not sure how much it will run me but when I get the invoice Ill let y'all know. He also was more than willing to sell the parts, but when you realize that 350 in parts sells for 400? For me it was an easy decision.
Sinthome, I was not intending to rain on your parade and hope that you understand I am just like you. Looking for a easier way, that is also more reliable than pvc and less costly than the 22 blank gun. My time to put the parts together that would be lost with my girls is worth the 100 bucks I would save doing it myself.
 
W^3 said:
Personally, love the idea and have been at it myself as well as I could see spending 200 for a APTA even if they were in stock. That being said, it looks like the folks at J&J sporting goods in Marietta Ohio have it figured out
91cV0aZhHkL._SL1500_.jpg
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I have found the 12g CO2 for
$.40 a piece to use with my APTA.

I still like this however. Thank You.
 
sinthome said:
Yikes! Ok, looks like there is sufficient interest in this design, I will get parts together to make a few more of these and get y'all some photos/video. At this point I have no intentions of making more than a handful of these and compensating myself for r&d plus parts/assembly. It'd be great if an arborist company adopted some of my design features into a launcher at some point, but until then I am just happy to get the perfect TIP, quick and easy and safely.

Here is a link to a basic breakdown of valve types for "spud guns".
http://www.spudgunner.com/spudgun-valves.php

As described, I am using the "Quick Exhaust Valve (QEV)" and they work excellently for this purpose.
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i have made a few air cannons in my day, i always wanted to go all out and make one with a co2 or compressed air tank like a paintball gun with a valve and pressure guage so u can fine tune the amount of pressure and reload faster, add a laser or red dot sight and make it come apart for storage/travel and your design would be sweet, but pricey
 
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