SpudFiles

The cannon is actually a coaxial: http://www.spudfiles.com/forums/blowgun-and-1-modified-sprinkler-valve-t23595.html

After fixing it with the piece of steel, it seems the threads are in a condition they are reusable.

It is possible I could put a large O-ring at the end of the screw fitting, and ...

Unscrewing the coupling is important to be able to service the piston.

I managed to fix the threads enough to be able to smoothly screw and unscrew the reducer bushing into the coupling. I did this with an angled piece of steel which I forced through the channels in order to press the bad threads ...

It's not cracked, the threads are a little broken. There is perhaps 80% of good thread holding it on, but there are really bad flat / double threaded spots on either side.

However, unless I can get it to thread back into the original threads somehow, it's not coming back from this one...

Hey Guys,

I recently added a sprinkler valve to pilot my 50mm piston cannon. It made an awesome difference, and I was looking forward to getting some epic shots out of it.

Unfortunatly, when I first screwed the new 50mm reducer in, I over tightened. This partially broke the threads inside the PVC ...

I would suggest a 3/4" pipe nipple, and then you cover the thread in epoxy, and screw the pipe nipple in.

The subject is all about overpriced spudguns that are available for sale

Not just manufacturing cost, but actual cost to the general public.

I wish it were that simple... The blowgun valve is broken to the point where air coming from the 1/8" side will leak out the valve lever. Fortunatly, I managed to salvage the valve enough that the 1/4" side was air tight.

I need to add the shraeder to the sprinkler body, possibly in a hole below ...

Consider these the prelimary pictures...

Okay, after filling the equalisation hole on the sprinkler valve's diaphragm with epoxy, and redrilling to 0.7mm (I drill a lot of PCBs, and have all sorts of small drills :-D ) the cannon now works great.

When I drilled out the blow gun to try to increase flow, I ended up drilling into a valve ...

That $3.5k cannon looks like the are over charging... I dont think that PVC sheet would be cheap, but I still reckon $3.5k is too much. Good that he's using the right valves though. I'm sure I've seen some for sale cannons with a solenoid sprinkler valve for the main valve...

Anybody reckon they know the most expensive spray and pray sold in a store?

I'll start the bidding at $1000NZD ($750USD) for this: http://www.testntools.co.nz/potato-gun-and-fishing-line-launcher-p29910.html

It doesn't have metered propane, a mixing fan, fancy ignition or any cool features. This ...

The blowgun is a cheap one from mitre10 that came in this kit: http://www.mitre10mega.co.nz/shop/powertools/air_tools_compressors/medalist_20_piece_air_tool_accessory_kit_260684/ except mine is a smaller kit made by the same people (16 accessory instead of 20)

I will try reducing the hole to a ...

The piston activates fine with a 1/2" ballvalve. The fit between the wall is close enough that I can actuate the piston using my mouth (Mmmm, CRC..!)

I think the problem is that the blowgun isn't piloting the sprinkler valve fast enough. However, this seems strange since a solenoid can open it ...

I've done something wrong here. Standard blowgun (1/4" in 1/8" out) onto a modified sprinkler valve (has a spring inside) I bought from Mr Crowley. I pressurise to 50PSI or so, and then the blowgun lets all the pressure bleed out without actuating the cannon.

As a test, I replaced the blow gun with ...

Are you not at all worried about the 11PSI rating on the valve..?

There are other QEV on eBay, but to get one with a useable rating you have to pay more. They don't come in that awesome black package either...

@AircannonSweeden: You could make a semi auto gun with a sodastream tank. Using a QEV ...