copper aph

[coolocat]

Hello people I'm back.

Just finished building a copper aph today and just had to post.
Its all made out of half inch copper piping and brass compression fittings except for the pressure chamber its made out of pvc. I thought about the copper chamber and decided against it as I wasn't sure how I'd do it (any ideas on a copper chamber would be helpful)
Its just finished and I'm letting the pvc cement dry so I haven't tested it yet.
I also have some pics of the construction process so I can write a guide on how its built if ye want (even though the pic alone might be enough) just let me know

I plan on adding another pressure chamber as the one at the moment is fairly small.

Anyway heres a pic and any comments/questions are welcome

http://i288.photobucket.com/albums/l.../Image0051.jpg

[cantab]

How come you did the PC like that? I mean it will work fine I expect, but even by homemade standards that doesn't look like the easiest of shapes to use.

[Ben]

Looking good. The PC seems extremely tall and you'd probably find the balance at different angles to feel weird. I'd suggest finding some wider pipe and using that.

If you could write a guide I would very greatly appreciate it. While to you and me a simple picture is all that's necessary, most people have no idea where to start. So it's not just me who'd appreciate it.

[Silence]

Looks good. Fortunately, those fittings are removable, so you could easily use another type of pressure chamber if necessary. It looks like you're using thin PVC right now.

[coolocat]

yeah the pc is extremely tall (a foot to be exact) The pvc i used was 1 and a half inch and in the plumbing store where I got it they said it would work fine for what i was using it for so fingers crossed . Anyways I was just wondering should I email you the guide Ben or just post it here on the forums

Finally I don't know if this has been done before (it might have been i haven't checked) but I made the pump seal out of a rubber tap washer that i cut to size using the copper pipe and then heated it and flattened it so it would mushroom out and then screwed it on the top like a plunger i thought it wouldn't seal but i worked perfectly. I plan on making a pump using an o ring as well its just that i had none.

anyway heres a pic of the pump:
http://i288.photobucket.com/albums/l.../Image0062.jpg

[Ben]

You can email it to me or post it here. Whatever works best for you is fine.

I haven't seen a pump made like that but it seems to be an interesting method. The picture's blurry but I understand what you did.

[Drenchenator]

Nice homemade!

That's an interesting method to make a pump seal. How'd you get the idea?

Did you test the gun yet? If so, how far did it shoot?

We don't have a lot of stuff about copper APHs, so a guide will be great.

[coolocat]

Thanks for the feedback guys . I was at home and found these rubber tap washers in my dads van and decided that instead of using o rings that I use these would use these instead it takes a bit of heating to melt the rubber slightly and then flatten it out but once you do it works perfectly so its really just trial and error until you get a good seal.

I think I'll email you the guide Ben as it would be easier for me to do as I'm still stuck in the olden days of dial up connection lol and uploading photos takes a long time. I'll mail it tomorrow sometime.
Also I've made a change to the water gun since the last few pics. I've changed the pc to a fizzy drinks bottle as the other chamber was leaking air out the top and it was hurting the range and shot time.

Anyways heres some stats for now. :cool
Pc capacity = 2000mls
range = 50 feet
nozzle size = 1/4 inch
output = about 300mls /second roughly 10x (I think don't hold me to that)
shot time = about 6 seconds

Heres a pic of the water gun with the new pressure chamber:

http://i288.photobucket.com/albums/l.../Image0048.jpg


I post some shot pics tommorrow as well

[aEx155]

I can't really tell from the picture, but I really want to know how you attached the bottle. Did you just thread it into the tee-joint, or did you glue it or something? I've been able to do it before, but it'd be nice to have another way to attach bottles in case I ever need to again.

I did something similar with a rubber stopper, a small wood screw, and a wooden dowel. Your way seems much better. Do you know how much pressure the seal can hold? I might do something similar to solve a pump problem I have.

[cantab]

Same here on wanting to know how the bottle's attached. Thanks for tips on the pump.

Also, it's good to hear you're getting good performance with quite small diameter pipe. I was going to go larger on the barrel for mine, 22mm or about 5/6 inch, but it seems I may not need to. OTOH if I do, it may be good to compare.

One other thing I would say - I'm sure you could make all the sections of piping smaller. All those 2-inch bits could go down to 1 1/2 inch easily I reckon. I believe compression fittings do not require you to grip the pipe to connect or disconnect (like threaded connections do), so you can reduce it to very little pipe showing. This will make the gun lighter and more compact.
Of course the size is also determined by the pump stroke. Shortening the gun will probably shorten that also. Some would consider that a drawback.

What have you used for the nozzle?

Oh, and finally, obvious snag with copper guns - what's the empty weight?

[coolocat]

The bottle is attached using plain old super glue (loctite is the brand) but it works extremely well and doesn't leak or anything.I had a minor mishap today where i pumped to much and the bottle burst at the top but the super glue never gave way at the bottom i was amazed I just replaced the bottle.

http://i288.photobucket.com/albums/l.../Image0052.jpg

In compression fittings there is a little groove at the top of the tee joint can you see it in the pic below if you drill out the hole at the top of the bottle and make it a little bigger it will fit into this groove. Then just apply superglue to the groove and push the bottle onto it.
I find if you layer glue along the outside of where the bottle and the tee are joined it will stick better. (sorry if this is confusing just tell me and I will post detailed pic of it being done )

http://i288.photobucket.com/albums/l.../Image0050.jpg
aEx155 I'm not sure what pressure the pump seal will hold all I can say is that it seems to work without leak and it works quite well so sorry

Cantab now that I think about it I suppose I could have reduced the length of the pipe I used I was kind of following the measurements used in Bens aph guide.
In the nozzle I used a 1/4 inch air coupler and a threaded reducing bush to reduce down to a 1/4 inch (I'm not sure if that sounds right I'm not so good on terminology I just went in to my local plumbing store asked how to reduce fron half inch to 1/4 inch and this is what they gave me lol 0
The empty weight of the gun is about a kilogram and a half.

Finally here are some shot pics

http://i288.photobucket.com/albums/l...aterstream.jpg

http://i288.photobucket.com/albums/l.../riotblast.jpg

[Ben]

That's looking pretty powerful. You should be able to improve range by trying some different nozzle diameters. The nozzle you're using right now is breaking up fairly early so I'd imagine a larger one would be better.

Weird that the bottle broke before the glue connection to. I would have expected the opposite.

I don't know if you've email me the guide but I haven't received anything. If you're done feel free to email it to me.

[Silence]

Those streams look rather turbulent, which is surprising considering you're using manufactured pieces. I'm not sure what can be done about that; a laminator may help a little but probably not too much.

Bottles have much thicker plastic around the neck than, say, around the side. That said, yours exploded at the very end, where the thick plastic stands are. Now that I think about it, most cylindrical plastic containers do have weak points in the very center of the end without the lid. Epoxy might be able to strengthen that well.

[aEx155]

Those shot pics are really good. Like SilentGuy said, a laminating or a conical nozzle should help even the flow out; otherwise, you're not getting as much performance as you could.

Originally Posted by SilentGuy

Bottles have much thicker plastic around the neck than, say, around the side. That said, yours exploded at the very end, where the thick plastic stands are. Now that I think about it, most cylindrical plastic containers do have weak points in the very center of the end without the lid. Epoxy might be able to strengthen that well.

I don't think epoxy would help; I believe epoxy is good for holding things together, but I'm not sure of it's tensile strength

I remember some time back on a bottle rocket site (buy do I reference those a lot...) that in order to strengthen a bottle, a guy wrapped it in some type of fishing line that didn't stretch, then rubbed it in some kind of glue to hold it in place. Another method was to use carbon fiber meshing and whatever adhesive the goes with it wrapped around the bottle.

Basically, if you're into strengthening the bottle, using something that has a high tensile strength and use glue to hold it in place; otherwise, use lower pressures.

[Silence]

I understand your point - that slathering the outside of the weak point with glue isn't going to help because the pressure can push it out anyway. But epoxy still bonds to (most) plastics better than anything (not that there aren't exceptions). The best solution would be a metal or plastic disc/object epoxied to the inside of the bottle. It would obviously be hard to maneuver into place, though.