Build log: New CAP water gun

[Drenchenator]

Nice find, Ben! I'm sure many people will find it useful.

Ben and I were talking about the lack of pressure-rating fittings at Lowes and Home Depot. It was kinda funny that they sold pressure-rated pipe yet no fittings. The big difference was the length of pipe on the fitting that overlaps onto the pipe. Pressure-rated fittings have more length to these sockets; non-rated, less.

[Silence]

This is actually a pretty thorny issue. It's no longer easy to recommend just going out to a hardware store and buying the right fittings, and ordering them from an obscure seller online may be a little too much to ask. It's strange how we immediately write off all thoughts of using cellular core pipe, but fittings are easy to gloss over. I'm not sure how to deal with the issue.

I'd at least feel better if plumbing stores like Noland's offered pressure-rated pipe (I'm not sure whether or not they do). Or maybe we could decide that it just doesn't matter for our use and recommend cell core pipe. In fact, given the heights of some buildings that likely use cell core pipe, and given 14.7 PSI per 30 feet of elevation, non-pressure rated pipe might be okay in the end. Interesting.

[SSCBen]

It is unusual that Lowes and Hope Depot have no problem stocking pressure rated pipe but stock few pressure rated fittings. The only consistent large pressure rated I've seen there are caps. The cap I'm going to use in CP45 is pressure rated. As to why... your guess is as good as mine. There doesn't seem to be much logic put into what parts are available.

One thing to consider is that DWV doesn't necessarily mean not for pressure. For example, the 4 inch pipe used in Supercannon II is DWV but clearly has a pressure rating (check out the picture). DWV fittings seem to just have shorter sockets in most cases, so I assume they can hold pressure rather decently, just less than would PW fittings. DWV often just means no pressure rating is provided. I'm sure if we did the same test procedure that they did to determine the rating of the pipe we could determine the rating of a DWV fitting.

Cellular core pipe is definitely weaker so I don't recommend using it in any circumstance. But you're right that tall building probably do use it and it probably does hold a good deal of pressure. I bet pipe manufacturers give each pipe and fitting a certain minimum in pressure rating because of things like that and ignorant spudders who don't know about pressure rating. They don't want to deal with lawsuits. Of course, that's just speculation.

If someone wants to use DWV fittings that's their choice. Since we're using water the safety is improved, at least in part of the water gun, so I think it's acceptable depending on the design. With that being said I'd never recommend using DWV if you have access to other pipes. If you have to order parts, oh well, it happens.

This design I don't think is for everyone so I'm not too worried about asking people too much. The $70 regulator and $70 air tank should turn most people away.

[Silence]

I've done a bit of searching and it looks like, in terms of strength, the order is:
Schedule 120 > Schedule 80 > Schedule 40 > Schedule 40 DWV > cellular core DWV > thinwall

I'm just wondering if we should have a specific recommendation when buying pipe, that is, a recommendation of something other than pressure rated pipe. I feel at lower diamter things really don't matter, but with 2" pipe and above there could definitely be some concerns.

Edit: Here's an informative post on the subject.

[SSCBen]

Informative thread. Seems to verify my thoughts that DWV just has a lower pressure rating. Given that I don't see a point in using pressures above 60 PSI in most water guns I think DWV is safe but can't be highly recommended.

A few things in that thread are a little off like how density somehow determines strength. I thought the strength of the material determined the strength. I know what they mean, but it's poor and misleading word choice.

Another thing to note is that thinwall can be fairly strong, so the bottom end of that spectrum varies. I have some thinwall 1/2 inch and 3/4 inch that still have respectable pressure ratings. I use them for structural parts mainly. The 1/2 inch thinwall is great to mount Nerf barrels in to prevent them from being damaged.

[Drenchenator]

Nice find! I never really though much of the difference between DWV and schedule 40 pipe until now. I guess the smallest things can make big differences at times, though fortunately enough DWV is still good for most of our applications. I don't trust it for anything involving high pressures now though.

Thin wall seems too much like a structural element to me. I know you can move water through it, but the second some static pressure builds, it's liable to fail. It's rigid enough, and that's in my opinion it's major advantage.

[SSCBen]

Drenchenator, here's another page you might find useful: http://www.spudfiles.com/spud_wiki/inde ... _Rated_PVC

It's all about identifying pressure rated PVC pipe and fittings. I should probably make it into a sticky.

[Silence]

Schedule 40 > Schedule 40 DWV > cellular core DWV

Now I'm wondering: What's the difference between Schedule 40 DWV and regular pipe? Unless DWV is cell core, which makes it identical to the next item in the listing, I don't know what the difference could be. That said, there's not much information out there so I probably jumped to some conclusion about the order.

Ben, are you sure DWV isn't cell core?

[SSCBen]

DWV can really be anything. It can be pressure-rated like the pipe in Supercannon II. It can be simply less strong pipe or fittings. It can be cellular core as well. DWV is ambiguous, but largely simply less strong pipe and fittings. If you have a DWV fitting with long socket holes from what I've read you can essentially accept it to be pressure rated because there's often no other difference between fittings.

[Drenchenator]

Drenchenator, here's another page you might find useful: http://www.spudfiles.com/spud_wiki/i...sure_Rated_PVC

It's all about identifying pressure rated PVC pipe and fittings. I should probably make it into a sticky.

Another good find. The section about identifying by looks clears up some vague little details I saw from before like the socket depth among others. I'd make it a sticky, or just add it to the PVC reference sticky.

[SSCBen]

I still haven't received the regulator shipment or a reply back to my email about the regulator shipment. I've sent another email to a bunch more addresses I found on their website and hopefully I'll get some sort of response. I've also emailed Captain Slug to ask how long shipping took for him.

If I don't get a response back in a few days I'm going to tell PayPal to give me my money back.

[SSCBen]

I called the phone number given in my email. Turns out that number was changed and I got some guy who never heard of Centerflag Paintball products.

More digging later, I found a number for the owner of Centerflag so I gave him a call and left a message. This number is still working and seem to be correct. Hopefully he'll get back to me soon.

After doing some searching I learned that Centerflag is essentially shut down at this point likely as a result of high gas prices. So it's not looking promising. I'll probably ask PayPal to give me my money back and then use a Palmer Stabilizer.

[Drenchenator]

That doesn't sound good. Are you still going to get the paintball regulator at this point, or have plans changed?

Have you thought about having a structure to this gun? It looks like there are going to be a lot of parts just seeming floating around; a solid structure will hold it together well.

[SSCBen]

I'm definitely going to use some sort of paintball regulator, but perhaps not that specific regulator. The cheapest Palmer Stabilizer seems plenty adequate. I'm going to give the Centerflag people one more day before I tell PayPal to give me my money back because I never received any product.

A structure will be made from wood from what I'm planning at the moment. Something basic should work.

Edit: I've asked PayPal to give me my money back. Hopefully I'll have some money back soon because I'm low on funds and this project and my others can not continue without more money. Google should pay me in a few days but I want to save that money for hosting and domain costs.

[SSCBen]

More time is being wasted as I wait for PayPal's response. The seller isn't responding so I assume no one checks that email any longer and my money is still deposited in the account so I'll get it back. On July 5th if the seller doesn't respond the case will be decided in my favor, so I'll know then if I get any money back.

Interestingly, my email to Palmer Pursuit hasn't been responded either so I'm going to give a call to them tomorrow. I don't know if they're slow or what, but I'll need to know the maximum flow capability of the regulator to know if it's adequate. Paintball is very different from water guns, after all.

Edit: A Palmer Stabilizer can regulate pressure down to 0 PSI so I won't need a second regulator with one. That's actually very good for my design because it'll make it lighter and smaller. It'll be slightly more expensive than the old CenterFlag regulator but it's probably worthwhile.