SpudFiles

I have a few questions regarding the construction of a coax cannon.
1) Has anyone attempted to utilize more than one barrel inside the chamber?
2) Do I have to use a coupler and a bushing for the ends of the chamber or is there a way to use a bushing straight into the chamber?
3) If I were to build a coax with a 2" chamber, would a 1 " sprinkler valve be overkill?

Thanks

(1) no, lack of proper fittings has prevented that.
(2) yes, you must use a coupler and bushing. Unless you can find a bushing that fits quite well.
(3) no i dont think it would be overkill. I think it would pilot quite well.

(1) It is possible with copper fittings - there are 22mm -> 2/3/4 x 8/10mm fittings
(2) You dont get (pressure rated) Reducing Couplers where you are?
(3) What mopher said

1) dual barrels would require custom epoxy casting.
2) epoxy casting would work great
3) Pilot valve size is not a matter of over kill its more a matter of performance versus cost. But that would work great for that chamber.

Has anyone heard of or used Starboard? I have a lot of it at work and I was wondering if anyone had used it in a spudgun before. Its made from recycled plastic and I can get it in 1/4 and 1/2 sheets, similar to plywood. So I am thinking of making a coax piston and bushings for the ends out of it.

spudgunnerwryyyyy wrote:1) dual barrels would require custom epoxy casting.

Indeed I often though about doing this but always found it better to just use a single large barrel and use a sabot to fire multiple projectiles.

@hotwired
I think he is talking about a bushing, the ones that go inside the big pipe, not a reducing coupling, though it does seem more practical to use a reducing coupling, given that there are no bushings that actually fit in the pipe, since they have the same OD as the pipe, so require a coupler like he was talking about.

A 3"-2" bushing fits well in 4" pipe, I did that for an unfinshed coax and it worked great.

ShowNoMercy wrote:I have a few questions regarding the construction of a coax cannon.
1) Has anyone attempted to utilize more than one barrel inside the chamber?
2) Do I have to use a coupler and a bushing for the ends of the chamber or is there a way to use a bushing straight into the chamber?
3) If I were to build a coax with a 2" chamber, would a 1 " sprinkler valve be overkill?

Thanks

I believe #1 has been done, I'm not sure though

frankrede wrote:I believe #1 has been done, I'm not sure though

luckythirteen on spudtech had made a twin-barrelled cloud but I don't remember anything larger.

I think I am going to go for two barrels, probably the 1/2 inch CPVC stuff. Since I will be using a piece of plastic instead of bushings I can make however many barrels I want to, however I plan on using a 2inch pipe for the chamber, do you think that with two barrels in it the volume available may not be enough?

even if the barrel's o/d was 1 inch, having 2 barrels in a 2 inch chamber would still give you a C:B ratio greater than 1:1 if your barrel was as long as your chamber, so you should be fine.