What did i just buy?

[Just1ofgod]

sweet score i had plans to build something alot like this

[Alex345]

I'm jealous. That's one cool valve, hope to see it on a ~200PSI cannon in the near future

I guess because it is all o-ringed and what not, actuating the piston would decrease the (atmospheric) pressure in that middle bit if you blocked the hole, thus creating a small vacuum. If that is indeed what happens, just leave the hole open and don't worry about it as no chamber or pilot pressure should reach that middle area.

I'd recommend hooking up the fill line to both the chamber and pilot but with a ball valve to close off the chamber from the pilot when it comes to firing the cannon. Basically means you have a safety valve on the cannon too since triggering the pilot valve probably wont actuate the piston valve if the chamber line is still hooked up to the pilot.

Oh it's gonna make one heck of a cannon if it works! I was thinking about making a line from the tank to the valve as well, i wonder if i would re-route the pilot air into the second hole, would that cause a faster opening time? Or would it be barely noticeable?

ah...



you'll need to loop the pilot into the middlesection for it to pop open ..
Or..take out the bottom center O-ring and THEN plug the side.

I was thinking about that to accelerate the opening time, but i'm pretty sure the vale would also function if the pilot air would simply be vented into the atmosphere.

[MRR]

you'll need to loop the pilot into the middlesection for it to pop open ..
Or..take out the bottom center O-ring and THEN plug the side.

It doesn't look like it is necessary to pressurize the middle section. If you use a 3-way valve on the pilot and loop it to the chamber, it would work like a chamber sealing piston valve.

[Alex345]

I'm going to try and visit some specialized stores today for the right pieces, and i might have a lead on an old compressor tank to use as a chamber! I will take the valve with me, maybe some of the store owners can tell me what it is exactly and what it would cost new

[Alex345]

Ok, i found the downside of owning a big valve; big pipes! The valve is 6/4 which is just a tad smaller than 2" pipe, which as i found out, is not cheap :p I went to over 3 stores today and they all had the pipe in blank form but no means to thread it...

Finally they sent me to a specialized heating system installer who are going to cut the pipe to size and thread it... This is so NOT going to be cheap.

The lead on the tank was a dead one as well, it was thrown on a pile of rusting scrap metal exposed to the elements. And yet the owner did not want to part with it... It had a 2" thread on the outside, just ONE adapter piece away from a perfect fit directly to the valve 0.0

Anyways i'm going to drill a hole into an old compressor tank i normally use in my car for my horn, and have someone weld a 6/4 nipple to it so it screws directly onto the valve!

If i want to re install it back into my car i can simply crew a cap over the nipple with some teflon and done :p

I still got the most expensive part of this to-be cannon for dirt cheap so i'm still 100% behind this project, and i'm sure that when i shoot it for the first time, my feelings about the high price of the barrel and the bad luck with the other tank will disappear

[MrCrowley]

Ok, i found the downside of owning a big valve; big pipes! The valve is 6/4 which is just a tad smaller than 2" pipe, which as i found out, is not cheap :p I went to over 3 stores today and they all had the pipe in blank form but no means to thread it...

I assume that's 1.5" nominal bore pipe thread (probably BSP)? Do your hardware stores not stock galvanised iron pipe and fittings at all? I know other people in Europe don't seem to have a problem finding them. 40mm galv. iron fittings are fairly cheap too, only a few dollars a piece. You should hold off on going to the specialised heating system installer until we work out why you can't find any galv. iron pipe or fittings.

[Alex345]

The pipes are plentiful in most common hardware stores but only to about 1" dia. A specialized store i often visit has slightly lager pipes but nowhere near 6/4 which was 48mm i think. They do stock 6/4 fittings and even larger ones but not the pipes themselves.

Believe me iv'e tried to find it in a normal store, but such sizes of pipe are rarely used in normal home construction, but in large heating systems built by specialized companies. Thus the average Joe rarely needs pipe this size, at least that's my theory :p

[MrCrowley]

nowhere near 6/4 which was 48mm i think

I assume we're talking about 6/4 nominal bore and not the real diameter?

A 6/4" nominal bore fitting = 1.5" nominal bore = 40mm nominal bore, which I think has a ~42mm inside diameter and ~48mm outside diameter in galvanised pipe and fittings.

While hardware stores in NZ are similar and don't stock galvanised iron pipe and fittings above 1", there are plenty of more specialised stores that do. A plumbing merchant or a bathroom store that has a trade section should stock galvanised pipe and fittings (look online or in your yellowpages for a place like like Reece plumbing, which we have in Aus/NZ). An air fittings/pneumatic/air compressor store may also stock galv. iron pipe above 1" (example: Ash Air). You could also check a hose fitting store, an example of what I'm talking about is a store we have called ENZED and they stock a wide-range of galv. iron, brass, and hydraulic fittings and pipe.

You could also try to order online from some UK websites, eBay, or other European sites.

They do stock 6/4 fittings and even larger ones but not the pipes themselves.

You could try to make a chamber from barrel nipples, which are technically fittings but are really just short (~20cm>) lengths of pipe with threads at both ends. Just use a couple of those and join them with couplers.

What size chamber are you after anyway? If you can get a 1m length of pipe made and threaded for you for not too much, then you may as well do that as you can already buy the necessary fittings and adapters to connect it to the valve. If it's going to cost a lot, there are cheaper ways of making a chamber for this valve (such as: finding a store with pre-threaded pipe, using multiple barrel nipples and couplers, or using a different material for the chamber).

[Alex345]

The chamber will be an old compressor tank (15l i think) and i will use the pipe purely as a barrel. I ordered a threaded piece of 2m, the price is around 17€ per meter so about 34€ for the barrel, problem is the labor cost for threading the pipe. I have no idea what that will be.

I'm from Belgium, and 50€ per hour is not unusual :p I think the pipe is also named as 1 1/2... So many sizes :p

[MrCrowley]

I'm from Belgium, and 50€ per hour is not unusual

Yeah that sounds about right. That's a very expensive barrel though. Does the galv. iron pipe have a seam or is it seamless? You definitely want seamless pipe.

I paid about the equivalent of €25 for a 48mm (i.d.) stainless steel pipe 2m long and then I paid a local welder the equivalent of €10 to weld a 50mm galv. iron threaded nipple to one end. I also paid about €15 for a 1.5m long 66mm (i.d.) steel pipe (with 3mm walls) and another €10 to get a fitting welded to it. I've also bought a 1m length of 44mm (i.d.) aluminium for about €15 and epoxied my own brass fitting with threads to it. Using stainless steel or aluminium means your barrel might be significantly lighter than if you used galv. iron.

I bought those from a NZ auction website and postage wasn't too much since the sellers were located in my city. It might be more difficult for you if you can't find anyone locally who is selling cheap pipe by the metre.

Sorry if i'm annoying you, just letting you know that there may be other, cheaper, options available to you

[Alex345]

Why is everything so cheap there? :p For me it's 17€ for just 1m of steel pipe with seam and not even galvanized...

Believe me, i'm open for any other options :p And all help is appreciated Maybe i should contact a small plumber instead of a large company?

[MrCrowley]

Why is everything so cheap there? :p For me it's 17€ for just 1m of steel pipe with seam and not even galvanized...

It's really expensive if you buy from a store so that's why I buy most of my stuff secondhand from people online. Basically, we have a site like eBay but only for people in New Zealand.

The stainless steel pipe was from a guy who had bought pipe to make a handrail for his company but he had some left over so he sold it cheap online. Though, the 66mm steel pipe was from a company that sells all sorts of steel pipe, tube, sheet, and fittings. Maybe they just had extra stock they wanted to get rid of so sold it cheap online.

I'd advise against buying the seamed steel pipe as the seam is really annoying when you want to shoot projectiles that are a close fit in the barrel. Perhaps ring a few local businesses and ask if they sell any pipe by the metre; they may have some scraps or off-cuts that you could buy.

Otherwise, check a scrap-yard or other businesses that buy metal from people and pay them per gram or kilogram. They should sell you the pipe at just a bit above scrap metal price, meaning you're paying solely for what the metal is worth and not what the pipe is worth.

There are a few Dutch and French members on this forum who might have better suggestions for where to find cheap pipe.

[Alex345]

I will try to cancel the order for the pipe, if i'm too late i'll just buy it ofcourse. And if not i'll try to find the right barrel and weld it to a steel fitting

Any Dutch members are free to hop in and help XD

[Alex345]

Well the company was closed during the weekend so i called this morning and it was already made for me, i did not pay anything in advance nor did i leave any contact information... But i'm an honest guy, so i'll pick it up tomorrow and see what it's gonna cost me :p

But AT LEAST i have my barrel xD