PVC Housing: Please Evaluate My Design!

[makomike]

Yeah, good point about light! Got caught up in theory rather that reality. With your other post, I too was concerned with the flex of the pvc. I think it would depend on how connections were made. I have seen pvc do a lot of flexing in the pool business. Effluent pressure between a pump and filter run around 20 psi and you can definitely see the pipe flex, especially at start-up when pressure may reach 30 psi. In older system where the pipe has been there a while, it is permanently distorted. Schedule 80 pvc would make me more comfortable. Again, the connections or seals would be the factor.

visiting family in your area before heading to Maui and would love to dive. Got any diving around your parts. Heading home to Indiana in a couple of days and won't be able to dive for a month. I'm getting the shakes just thinking about going that long without getting wet.

never been to Hawaii. The wife and I are very excited.

 

[V. G. McGillicuddy]

Thank you all for your opinions!
After reading your posts, I think I will use the clamps instead of the plug. And using the remote to power up is an excellent idea that never ocurred to me.
As for the veiwfinder, I was just going to rig up some kind of sight on top of the tube to give me a general idea what the camera was seeing. And for the handles, I will probably glue or strap them onto the outside so as not to compromise watertightness with screws/bolts.
I just thought of another idea. What if I used two end caps (each with a window in it) and instead of clamping them to the PVC body, I could figure out a way to clamp them onto each other and squeeze it tight, like a lens guard on a rifle scope? That way, the body itself will remain uncompromised, and If one of the windows gets scratched, I can replace it easily. Any thoughts on that?

One last thing: What is "Fatigue Life?"

Thanks Again,

V. G. McG.

 

[diversteve]

I just thought of another idea. What if I used two end caps (each with a window in it) and instead of clamping them to the PVC body, I could figure out a way to clamp them onto each other and squeeze it tight, like a lens guard on a rifle scope? That way, the body itself will remain uncompromised, and If one of the windows gets scratched, I can replace it easily. Any thoughts on that?

I'd get away from the idea of using end-caps with windows in them. You're just adding complexity - and more potential leak points - for no apparent reason. Any poly/plex that's 1/2" thick will stand up to the pressure just fine. You can have someone in a machine shop cut you a couple of circles if need be, although I'm thinking you can buy them pre-finished somewhere online. Plus realistically you should probably fix the front cap semi-permanently to the housing, the likelihood of scratching it is pretty small - especially if you extend it's mounting out past it's edge slightly - not too much or your camcorder will vignette(film the edge of the housing at extreme wide angle)

Ikelite used to do what you're describing on their early tube housings. They had a long metal strap that ran the full length of the housing with clamps fastened on each end. I occasionally see them on eBay. They're black with clear endcaps - they predate the red metal cast housings. I think the tubes were aluminum.

btw, Ikelite sells a lot of useful parts that may be of some help to you. Including a clear molded housing that looks like it might work for small cameras. Here:

http://www.ikelite.com/web_pages/parts_index.html

 

[diversteve]

visiting family in your area before heading to Maui and would love to dive. Got any diving around your parts. Heading home to Indiana in a couple of days and won't be able to dive for a month. I'm getting the shakes just thinking about going that long without getting wet.

never been to Hawaii. The wife and I are very excited.

Mike,

There is some local lake diving around Phoenix. The best is probably Lake Pleasant, just a few miles north of Phoenix. There are other lakes to the east of Phoenix, but I've read recently that the viz is way below normal - like 5'. If you do decide to dive here, it's full 7MM now, Pleasant is fed by snow run-off - sounds crazy in the desert, but you know we do have this little hole to the north called the Grand Canyon here.

I don't lake dive, but if you wanted to try it, there's a group from a local LDS, Scuba Specialties - www.scubaspecialties.com - they post their events on their forum there. They often do a Thurs. night dive.

You're going to like Maui. It's the same, maybe better viz than you're used to. I've seen what the DM estimated was 120' viz off Molokini one year.

Must do dives once you're settled: Molokini Backwall including Shark Condos - during whale season - I think now thru April - the humpbacks sing and it affects your body, the Cathedrals at Lanai, Sharkfin at Lanai. the St. Anthony wreck - the turtles have taken to sleeping on it's deck this year. I've never had a bad dive in Hawaii.
My buddy was just there in August, they swam with Mantas on a dusk dive inside Molokini Crater, somehow Ed Robinson guessed they would be there.

Apologies to V.G. for hijacking his thread briefly.

 

[Nostromo]

V.G.

Fatigue life is the number of times something can withstand stress cycles of a given severity. For example, lets say you end up gluing some plex onto the end of a PVC tube and successfully pressure test it to eighty feet. Later due to repeated cycles of pressure loading the seal could fail at reduced depth. Typically Engineers will build something to withstand 150% of the load it's expected to normally endure. Most materials have an infinite fatigue life below a certain value. A good example of fatigue life in action is when a fifteen year old aluminum scuba tank explodes while being filled. That's what a hydro tests for.

Anyway, my point was that what you got away with today might just not fly a year from now. I would guess, (and I stress the term "guess") that as I and several others mentioned above that the amount of available light will keep you above any depth that would seriously fatigue a well built housing.

e.a.e.

 

[diversteve]

V.G.

You should hook up with the guy in reply 3 of this post. He just made a housing using PVC for under $30. And he's in Wisconsin also.

http://www.scubaboard.com/showthread.php?t=116026

 

[WetDawg]

You have re-invented The Aqua-Vault Universal Camcorder Housing


http://www.atmoseal-eng.com/aqv.htm


I have one, it's great. It's the cheapest solution for an U/W housing I could find.

Never took it below 100' though. Seems like it would be fine.

 

[diversteve]

You have re-invented The Aqua-Vault Universal Camcorder Housing


http://www.atmoseal-eng.com/aqv.htm


I have one, it's great. It's the cheapest solution for an U/W housing I could find.

Never took it below 100' though. Seems like it would be fine.

Cheapest solution I've seen lately is the Nemo-100 on eBay:

http://cgi.ebay.com/NEW-low-cost-Un...oryZ4703QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

They start at $129.

 

[V. G. McGillicuddy]

Thanks all, you have been of great help! And also, in all likelihood, you have saved my camera from being flooded.

Next stop: Fleet Farm.

Thanks Again,
V. G. McG.

 

[ChrisA]

You will need a large wrench to tighten down the cleanout plug. They must be very tight to be waterproof. You would also need a vice to hold the housing. Bring teflon tape too. "hand tight" will not work.

About the window. The main reason for leaks is that the plastic flexes. A 6 inch end cap will have something like 200 pounds of force on it or much more if you go deep.

If you have a peir nearby you can test the housing without even getting wet. Just lower it into the water with a rope