In my medium sized city in Minnesota it is not classified as a firearm because it does not use a cartridge. It is however, regulated as if is a firearm because it can launch a projectile by the process of compressed gasses.

So I don't use it in the city limits.

I didn't see anything on that page that would indicate that bell reducer has a PW rating. The 2" socket in particular looks a little shallow.

Yeah, the pics don't tell the whole story. The 3 that I have all say 429-420, NSF pw PVC1, SCH 40 D2466. Spears manufacture. These are 4" to 2" bell style ...

starman wrote: Jmeyer, make the effort to find some SDR 21. Yeah, it's rare but it is available. Check your local Tractor Supply Center.

Found mine at Menards, special order 1-20' stick, don't recall the price but it was less than $1 per foot last fall.

Good luck.

flexpvc.com, part number 429-420. 4"to 2" bell reducer,pw, Spears manufacture. Much nicer than any of the stuff at Lowes.

Do you guys know if the two 90 degree fittings used to turn the corner for the barrel will restrict the expanding gases in any significant way?


How much is significant? How can it be satisfactorily measured?

If you are thinking of using a 4" barrel then you would probably use a pair of 4 ...

My 1.75 C:B combustion (over-under) goes bang very nicely without any projectile. Static Guard spray, non-fan, bbq twin spark. Wait until the wife is gone, give a 4-6 second spray, and watch the flames. Even with ear muffs it is loud.
I don't do it in the basement anymore, my brother reminded me ...

In my spray and pray with a BBQ igniter powering 3 sparks I get consistent results with .050" to .060" each. Metric I assume would be 1.2 mm to 1.5 mm each. Good luck!

I've had good luck with flexpvc.com on pressure rated 4 to 2 bells (spears parts).

use the wires it comes with and hook them up to a spark strip.

It doesn't take a rocket scientist to figure out how to hook them up, just use that big pink blob in your head that god gave ya :wink:

HA HA! You are correct, I had it coming. Never did like English class back in school anyway, guess ...

Hopefully I didn't miss the point of these posts, flexpvc.com has pressure rated "bell" reducers. 4" to 2" schedule 40 and 6"to 4" schedule 80. Last shipment had a problem and within a week I had the correct part with a prepaid envelope for the return. Good place.

$16.88 before sales tax at Wal-Mart in St Paul MN. How are you guys attaching them on your cannons?

Gotta be some less stinky alternatives that would give as much power. How about Heet gas line anti freeze, 99% Methanol, or starting fluid.

A dab of pvc glue on the inside of the barrel at the muzzle, topside.

[quote

I do think a short, squat cylindrical chamber with the same volume will out-perform a long, skinny chamber of the same volume, as well.[/quote]

Is that a practical thing to do? A 4" chamber would be tiny and a 6" chamber would take 2 and 1/2 men to lift it.

I use Isopropanol 99% (rubbing alcohol) in my mini cannon. It works really well, and very powerful if you atomized it.

The yellow container of HEET gas line anti freeze is pure methanol, works very well atomized with a small shot of Static Guard to ignite it. Make sure to drain the chamber after ...