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by Moonbogg
Mon Dec 28, 2020 2:41 pm
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Re: stainless steel tube burst pressure

Disaster averted? Also, you need to know the yield strength to make a calculation. Without knowing the grade of steel, assume it's the weakest stainless in existence, plus the weld seam.
by Moonbogg
Wed Dec 30, 2020 3:16 am
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Re: stainless steel tube burst pressure

If I had the money, I'd make 3 of every cannon I have and test two to failure under different conditions. That way I'd really know the safety factor in a practical way and discover the weak spots and failure mode. Unfortunately, you could buy a nice car for what all that would cost, so it is what it...
by Moonbogg
Sun Jan 31, 2021 9:03 pm
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Re: ElectroThermal Cannon

How much pressure are you going for? What will you be shooting out of it and what velocity are you going for? If the answer is "maximum power to shoot a bullet-like thing", then there's really only one formula I can think of that makes sense: 4140 (or similar strength alloy), burst disc, big bottles...
by Moonbogg
Wed Feb 03, 2021 3:30 am
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Re: Regarding the Legality of Hybrid Spud Guns in the USA

That's a great response from the ATF. I don't understand and never will why some countries treat spud guns as if they were literal nuclear weapons and the people who build them as if they were literally a dangerous and violent war lord in need of immediate imprisonment. It baffles me why any governm...
by Moonbogg
Wed Feb 03, 2021 3:45 am
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Re: "In the world of spuds today"

Get crackin! Feed us pics and vids.
by Moonbogg
Wed Feb 03, 2021 2:59 pm
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Re: Regarding the Legality of Hybrid Spud Guns in the USA

Don't beat yourself up over it. Bad things happen. That's why we try to be careful, but bad things still happen sometimes. We all have our stories and experiences. You shouldn't feel shame for what happened. It was an accident. They happen. Maybe try lead pellets instead? Steel tends to be pretty bo...
by Moonbogg
Wed Feb 03, 2021 3:03 pm
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Re: ElectroThermal Cannon

I'm pretty sure Larda holds the record for highest mix, at least the "public" record. 190X was totally insane.
by Moonbogg
Fri Feb 05, 2021 7:39 pm
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Re: Regarding the Legality of Hybrid Spud Guns in the USA

I almost blew my head off one time. I never considered the risk of it and no one ever mentioned it, but one day I walked out to the firing line to shoot a pistol and forgot to put my ear muffs on. So, I put them on with a LOADED PISTOL in my hand. I basically pointed a loaded gun at my own head whil...
by Moonbogg
Fri Feb 19, 2021 6:12 pm
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Re: Mechanical detention valve for high mix hybrid

People have had success using a spark plug connected to a stun gun at 10x. I use a cheap stun gun and it's been reliable. I used one of those super cheap step up voltage thingies and it broke. It just stopped working. I think I even tried a second one if I remember right, and it broke too. Not sure ...
by Moonbogg
Wed Feb 24, 2021 12:47 pm
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Re: Adding Multiple Sparks In Combustion Chamber

I have been using PVC potato cannon for about 2 years and I decided I wanted to make it shoot further. I use a grill igniter/spark plug wired up to 2 screws inside the combustion chamber to ignite the hairspray. One way I knew would make it shoot further was to wire a certain way with more screws t...
by Moonbogg
Thu Feb 25, 2021 10:51 pm
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Re: Victorian "Air Cane" brought back to life

Beautiful work. This thing is cool. The spacing issue between faces reminds me of the headspace of a rifle; it has to be just right. I like it.
by Moonbogg
Thu Mar 04, 2021 12:35 am
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Re: Unusual Ammo and Barrel Construction

You could make a combustion cannon and toast those bagels on their way out! Just kidding, that's probably a terrible idea. Honestly, I think the best option is to build something different. I'm thinking go watch the slingshot channel on youtube and get some rubber-powered ideas to launch the bagels....
by Moonbogg
Wed Mar 24, 2021 8:23 pm
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Re: Caselman air machinegun

I missed this before. This gun is awesome. Legit full auto rather than a constant airflow with a tube stuck in the middle of a container full of BBs.
by Moonbogg
Thu Apr 01, 2021 10:25 am
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Re: Pressure rating for Coaxial cannons

See link with external pressure ratings for PVC. They call it "critical collapse" pressure ratings. You can compare the critical collapse rating with the internal pressure rating. Critical collapse ratings: https://www.usplastic.com/knowledgebase/article.aspx?contentkey=777 Compare those figures to ...
by Moonbogg
Sun Apr 04, 2021 6:44 pm
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Re: Pressure rating for Coaxial cannons

What do you mean by buying an air tank and punching holes through it? Making a PVC cannon this large makes me especially uncomfortable.