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Anyone try a PVC Rocket?

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: jackssmirkingrevenge » Sun May 25, 2014 7:42 pm

If you tell me the volume of one of your launcher's chambers I will be more than happy to talk you through the math :)
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Re: Anyone try a PVC Rocket?

Unread postAuthor: BowerR64 » Sun May 25, 2014 10:44 pm

oh man home work? that ruins all the fun of this.

It changes depending on if i shoot from the outside or inside. Ill go with outside first.

3-1/2" outside dia, 3" inside dia, 18" tube length so about 45-46 cubic inches?
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Re: Anyone try a PVC Rocket?

Unread postAuthor: jackssmirkingrevenge » Mon May 26, 2014 7:17 am

For an empty tube, that's 127 cubic inches, 2080 cubic centimetres. We want 4.2% propane for an ideal burn, so (0.042 x 2080) gives us 87 cc. Head down to the drug store and buy yourself one of these:

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Jam the nozzle into a propane burner like so:

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Open the valve until the plunger reaches the 85cc mark

Remove the syringe, slowly squirt the content deep inside your chamber and you're good to go.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: BowerR64 » Tue May 27, 2014 5:58 pm

What about the refil butane things for lighters? i dont have a propane tank handy.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: jackssmirkingrevenge » Tue May 27, 2014 8:13 pm

Butane works well too, but you need less of it. It's butane that I use in the syringe fueling video.

For the chamber you mentioned, you need around 65cc.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: BowerR64 » Thu May 29, 2014 1:47 pm

jackssmirkingrevenge wrote:Butane works well too, but you need less of it. It's butane that I use in the syringe fueling video.

For the chamber you mentioned, you need around 65cc.


Whats its burn rate?

I find carbide burns fast like say 4F powder quick and its over. The hairspray is very slow like 1F its more of a push then a quick flash. It works good for the rockets

Something inbetween would be ideal, a little more power then the hairspray
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Re: Anyone try a PVC Rocket?

Unread postAuthor: Boomer58cal » Thu May 29, 2014 4:39 pm

BowerR64 wrote:
jackssmirkingrevenge wrote:Butane works well too, but you need less of it. It's butane that I use in the syringe fueling video.

For the chamber you mentioned, you need around 65cc.


Whats its burn rate?

I find carbide burns fast like say 4F powder quick and its over. The hairspray is very slow like 1F its more of a push then a quick flash. It works good for the rockets

Something inbetween would be ideal, a little more power then the hairspray


Someone please correct me if I'm wrong here.

Using your black powder analogy... hairspray=F, Butane=FF, Propane=FFF and Acetylene=FFFF

This isn't the most accurate of analogies, But it shows their burn rate in order.
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Re: Anyone try a PVC Rocket?

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Re: Anyone try a PVC Rocket?

Unread postAuthor: BowerR64 » Thu May 29, 2014 8:25 pm

Boomer58cal wrote:
BowerR64 wrote:
jackssmirkingrevenge wrote:Butane works well too, but you need less of it. It's butane that I use in the syringe fueling video.

For the chamber you mentioned, you need around 65cc.


Whats its burn rate?

I find carbide burns fast like say 4F powder quick and its over. The hairspray is very slow like 1F its more of a push then a quick flash. It works good for the rockets

Something inbetween would be ideal, a little more power then the hairspray


Someone please correct me if I'm wrong here.

Using your black powder analogy... hairspray=F, Butane=FF, Propane=FFF and Acetylene=FFFF

This isn't the most accurate of analogies, But it shows their burn rate in order.


I shoot black powder revolvers also and just from what ive found between the 2 the hairspray seems way slower and sometimes will blow out threw the touch hole where i put in the point and flame igniter and its only a 3/8" hole compared to the 3" opening on the oposite end. I dont think ive found anything good yet locally ive had the best luck with some old rave 3X stuff my friend had from the 90s everything ive found newer just seems like a dud. The best is static guard wich is newer ive found.

I should try butane beofre i judge its speed i guess.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: jackssmirkingrevenge » Fri May 30, 2014 4:53 am

I'll make a small morning beverage analogy sine that's what I have in my hand at the moment:

Using hairspray is like shaking a jar of contaminated sugar randomly at your coffee and hoping that it will be the correct amount for your perfect mug.

Metering the fuel on the other hand is like carefully measuring the correct amount of teaspoons of pure sugar which you know will be exactly to your taste ;)
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Re: Anyone try a PVC Rocket?

Unread postAuthor: Boomer58cal » Fri May 30, 2014 11:10 pm

Using hairspray is like shaking a jar of contaminated sugar randomly at your coffee and hoping that it will be the correct amount for your perfect mug.


Hahaha I love it

Some people also forget that you have to treat air like contaminated oxygen.

Take butane and propane for example. With butane you need a slightly lower percentage then propane, well this gives you slightly more oxygen in your chamber, it also gives you more contaminants.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: BowerR64 » Mon Jun 02, 2014 3:58 am

Boomer58cal wrote:
Using hairspray is like shaking a jar of contaminated sugar randomly at your coffee and hoping that it will be the correct amount for your perfect mug.


Hahaha I love it

Some people also forget that you have to treat air like contaminated oxygen.

Take butane and propane for example. With butane you need a slightly lower percentage then propane, well this gives you slightly more oxygen in your chamber, it also gives you more contaminants.


HAve you starte on your carbide setup yet?
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Re: Anyone try a PVC Rocket?

Unread postAuthor: Boomer58cal » Mon Jun 02, 2014 9:01 am

BowerR64 wrote:
Boomer58cal wrote:
Using hairspray is like shaking a jar of contaminated sugar randomly at your coffee and hoping that it will be the correct amount for your perfect mug.


Hahaha I love it

Some people also forget that you have to treat air like contaminated oxygen.

Take butane and propane for example. With butane you need a slightly lower percentage then propane, well this gives you slightly more oxygen in your chamber, it also gives you more contaminants.


HAve you starte on your carbide setup yet?


I just haven't had time. My Dad has been in and out of the ICU of our local Hospital for the last few weeks. Family first.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: BowerR64 » Mon Jun 02, 2014 3:52 pm

Ahh yeah my dad has been in a nursing home for a few years now. He smoked for about 60 years of his life and it all caught up with him. He still has his mind but he cant do much any more. He is almost completly paralized very little use of his hands left.

i sort of stole this design from that cheapcarbide.com site. His have a simmilar stand but thats about it.

This whole setup runs about $12. with the $1. grill igniter from walmart. Then a cut in half 9mm shell for the load. Ide say it sounds about like a 357 mag type bang its a sharp not to percussive bang and not alot of kick.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: jimmy101 » Tue Jun 03, 2014 3:39 pm

Boomer58cal wrote:Take butane and propane for example. With butane you need a slightly lower percentage then propane, well this gives you slightly more oxygen in your chamber
Ya, but the difference in the amount of oxygen (between propane and butane) is just 1%. Since few parameters for a spud gun are known to that level of accuracy the result is that propane=butane, at least based on the amount of O2 in the chamber.
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Re: Anyone try a PVC Rocket?

Unread postAuthor: Boomer58cal » Thu Jun 05, 2014 5:01 pm

jimmy101 wrote:
Boomer58cal wrote:Take butane and propane for example. With butane you need a slightly lower percentage then propane, well this gives you slightly more oxygen in your chamber
Ya, but the difference in the amount of oxygen (between propane and butane) is just 1%. Since few parameters for a spud gun are known to that level of accuracy the result is that propane=butane, at least based on the amount of O2 in the chamber.


Agreed, you would need a chronograph to tell the difference. Your variations in power from shot to shot would probably be greater than the difference between the two fuels as well.
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