DIY Video Housing a success...

[The Horn]

Way to go looks really nice. Any Idea where it might be leaking from? I opted for just the one removable end, how do you like the two?

Glad you got your pictures up, took me forever......

 

[Bobby_M]

I was wondering where the leak might be coming from as well. With 6" PVC, I'd recommend moving up to 4 latches on the lid just to ensure that the plane of the lid doesn't flex. I guess you can look at the O-ring's profile all the way around the circumference to determine if you're getting equal pressure.

The other place might be the pipe to coupling joint. I'd throw a bead of 3M 5200 or 5 minute epoxy on both to rule it out.

Finally, unscrew the latches and put a drop of the same sealant in the hole before retightening.

I also found one removable end fine, but the one benefit to two is being able to repair/polish both. However, the detriment is having a whole other O-ring point of failure to worry about.

I figured that if my fixed window is damaged, I'll flip my cam tray around. At least I know I can polish the removable end.

Bobby

 

[The Horn]

How tight are your latches? I downloaded a page from the manufacturer and set up my spring latches for 50 psi or the middle setting. Perhaps there is some flex to the coverplates?

Bobby, have you polished the lense yet? If so did you just use a buffing wheel and the correct acrylic buffing compound? if so what did you use?

 

[Bobby_M]

No, I haven't polished the lense at all. I've been careful enough so far that I haven't gotten any scratches.

Bobby

 

[kelpman]

I just now started reading through this thread on homebuilt housings.
I too was dismayed a few years ago when I wanted to put my video camera in the sea. I made mine over 4 years ago and it has been all over the world with me to over 120 ft.
I use JVC cameras and luckily, they all use the same IR code for stop/start and zoom in/out. I used a neodymium magnet in my glove to control the operations. Being that JVC controls with the same code I have 2 housings and swap the controller in both using velcro.

http://www.markwilson.com/SEAVIEW/seaview.html
http://www.markwilson.com/
However; the bummer was that if you pause for more than 3 minutes the camera shuts down and you must restart it physically with the switch. I have since used Ikelite control arms and have dumped the magnet switch. I figured that if people with 10K dollar cameras trusted them, why not I?

I admire everyone who has taken the time to build their own housings. It is one thing to shoot video, but another to know that you built the unit and it works well.

In response to a thread on magnets. Digital tape needs a minimum of 2000 gauss to even begin to erase a tape. DV is embedded fairly deep. Degaussers use alternating magnetism to erase tapes. Direct magnetism to a video tape does very little if anything. You may get a few dropouts here and there if you have old or substandard tapes but that is about it. Even with the pro degaussers, we find they don't erase the DVs very well. I used the magnets without worry and never had a problem.

The only problem that I encountered with the system before the control arms, is a few drops of saltwater from my glove or moisture in the housing. My older JVC would shutdown from condensation. A pack of Dessicant in the housing works great.

Weighting is an issue on international trips. I have industrial strength velcro on the outside of the housing. I take the hard weights from the resorts and put the velcro strips through them. There are many options, none are pretty but they work.

On my larger housing, I actually use 2 3 lb softweights on the inside. I like the housing a small bit positive.

I enjoyed reading the threads! I will be building another one soon for my new camera. I am getting some superbright LED's and building in a light system. I'm also putting a sealed lead acid battery in the housing to run the camera and lights on. (I hate recharging the @#$ camera.) I figure that if I have the weight the dang thing, I may as well put in something useful!

 

[Guba]

Great looking camera, Kelpman!
My design is much like yours, I think. I, too, chose a two-windowed design with both of them removeable. When I travel, I also have to attach weights to the outside. Instead of velcro, I use zip ties to attach hard weights to points under the handles. Due to their shape, the weights fit snug and don't rattle or move. I too use a magnetically actuated electrical system to start/stop my camera. Instead of a modified remote, however, I use a simpe solenoid to "punch the buttons". It works.
I've just recently tried to tackle the lighting problem. The photos in my gallery show what I've done. The lights are 9-element LED's. They're "off the shelf" flashlights but have a broad, soft beam pattern and seals with threaded aluminum connections. I modified them with additional seals and have tested them to a 4 atmosphere equivalent pressure and they've held up. They haven't been underwater yet, and I can't wait to take them on a practice dive.
Glad that you've joined the forum. Welcome!

 

[MichiganDiver]

What are some of the methods of attachment of your handle brackets to the housing? I am looking for something reliable and mechanically strong. I am considering gluing a piece of PVC to the outside to double the wall thickness, then inserting some threaded inserts to make the handle removable. But, there might be too much shear on such an attachment. My second thought is to run a strap through the handle bracket (somehow) and around the entire housing.

Let's hear what you've done and what your experiences have been.

 

[MichiganDiver]

I know the question was asked earlier in the thread, but I don't know if it was answered: what is the crushing pressure of PVC pipe? The pipe sometimes comes stamped with a pressure, but I think that pressure is for the fluid inside the pipe. I wrote to Harvel Plastics (www.harvel.com), and they were kind enough to send me a table. I have extracted the relevant values for 4 in. and 6 in. schedule 40 and schedule 80 PVC pipe. The complete table can be downloaded at http://www.harvel.com/tech-support-eng-neg.asp, but you need to register on their website first.

Note that pressure is expressed in pounds per square inch (psi) or inches of (fresh) water. Salt water has a density of about 64 pounds per cubic foot, which translates to a pressure increase of 0.44 psi for every foot of depth.

Diameter Schedule 40 Schedule 80
4" 190 psi (3487 in H20) 451 psi (12482 in H2O)
6" 90 (2491) 343 (9493)

These pressures should be considered as ultimate pressures, and an appropriate safety factor should be applied. Also, the factors are determined at 70 F. See the Harvel link for appropriate derating factors and more complete information.

[if someone can help me format that table better, I'd appreciate it :huh: ]

 

[Guba]

MichiganDiver, thanks for the data on the crushing pressures. I'm getting ready to build a version two with 4 in pipe, and it's reassuring to know there is an ample margin of safety pressure-wise. Unless my math is flawed, at 130 feet the pressure should be about 60 psi (around four atmospheres), so even six in PVC is okay. Glad to hear that since that's what I built my version one out of.
As for as handles, there are lots of ways to attach them, but I chose something like what you mentioned. I first glued a section of PVC to the attachment points on the body so I could use longer screws without going all the way through the housing wall itself. I then shaped a bar of aluminum to that it went completely around the housing, attaching with screws on the top and bottom. It's very secure and strong, but the handle isn't easily removed. Therefore, I kept it a bit narrow to facilitate easy packing and transport. Future versions will probably have detachable handles.
I have pix in my gallery, so you might take a look.

 

[kelpman]

Have you been to www.superbrightleds.com?

We were looking at some of the calcs on the new leds
http://www.cree.com/products/xlamp_new.asp

However; be careful with the viewing angle. I'm still working out the angles and the distances to get the best "flood" at 1-4 feet distance. I may need a diffuser.