| Author |
 Topic  |
|
yo_tyler
Apprentice
Canada
87 Posts |
 Posted - Nov 10 2005 : 10:41:32 AM
|
I need to build a cheep underwater camera that can withstand being down to 66 feet (~40PSI, 3atm). I think i know how i will build a shell for it, but i need to test it to see if it will withstand the pressures. What is the best way to do this? The camera is just one of the $20 walmart vga cameras, so if it does get wet, or implode, its not the end of the world. Also, the shell will be small, only about 4x8x6 cm.
"If the women don't find you hansome, they should at least find you handy" -Red Green |
|
|
Alessandro
Apprentece
Australia
18 Posts |
Posted - Nov 10 2005 : 3:38:23 PM
|
Tie a rock to the shell to make it sink, then a attach a long piece of rope to it. Get someone to take you out on a boat or something, and lower the thing 18m into the sea, leave it there a few minutes, pull it back up and see if it leaks.
"I have not failed. I've just found 10,000 ways that won't work. -Thomas Edison.
www.freewebs.com/sci-stuff |
 |
|
|
yo_tyler
Apprentice
Canada
87 Posts |
Posted - Nov 10 2005 : 7:01:41 PM
|
Well thats exactly what im trying to aviod doing, becouse i mind as well just take it with me when i scuba. i think i have a plan: if i can pressureise the inside to 3atm, and no air getets out, then no water should get in.
"If the women don't find you hansome, they should at least find you handy" -Red Green |
|
|
|
Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Nov 11 2005 : 09:16:35 AM
|
40 PSI isn't too big of a deal. I would get some ABS pipe, two end caps, and then some Lexan. Insert camera into pipe, glue one end cap on. The 2nd end cap would be the screw on type. You would cut an area to install your Lexan window, placing the window on the OUTSIDE of the cap and sealing it (use nuts and bolts to hold it in place). Should be good to at least 100 feet.
|
|
|
|
yo_tyler
Apprentice
Canada
87 Posts |
Posted - Nov 11 2005 : 11:42:34 AM
|
pipe is what i figured i wold use. the only problem is grinding a flat centrer hole in the end cap and then attaching the lexan. would a glue route be be better than a bolt-and-gasket method? And will 1/8 inch lexan be thick enough, because i have a leftover 1/2^2 foot?
"If the women don't find you hansome, they should at least find you handy" -Red Green |
|
|
|
Kale
Nobel Prize Winner
Canada
795 Posts |
Posted - Nov 11 2005 : 5:05:42 PM
|
Maybe layer the lexan to bring the strength up? Depending on how much you have...
|
|
|
|
yo_tyler
Apprentice
Canada
87 Posts |
Posted - Nov 11 2005 : 6:10:59 PM
|
layering the lexan would leave a thin layer of water between the lexan. with somany co-efficients of refraction. the camera wouldnt be able to focus.
"If the women don't find you hansome, they should at least find you handy" -Red Green |
|
|
|
cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Nov 12 2005 : 12:39:45 PM
|
you could cut everyhtign but the threads off of the endcap and use it in conjucntion with a couple 0 rings to hold the lexan in the hole.
AS for the double pane idea, if you put 2 together then seal the joint, no water would leak in.
http://daxter12.topcities.com <Updated:July |
|
|
|
Kale
Nobel Prize Winner
Canada
795 Posts |
Posted - Nov 12 2005 : 2:56:21 PM
|
quote:
layering the lexan would leave a thin layer of water between the lexan. with somany co-efficients of refraction. the camera wouldnt be able to focus.
"If the women don't find you hansome, they should at least find you handy" -Red Green
Actually I'd be more worried about partial filling between layers. Drops and streaks will corrupt the image the most. Layering is definately a last-ditch idea, but if you seal the layers well you MIGHT be able to get away with it. I'd recommend gasket sealing compound around the outer edges of each layer, and compress the stack tighly. Again though, it's just another thing that can go wrong, so you might just want to buy thicker Lexan. 
|
|
|
|
yo_tyler
Apprentice
Canada
87 Posts |
Posted - Nov 12 2005 : 5:57:44 PM
|
Ok, today i bought some 4" ABS, two endcaps (one removeable), the cheep-o camera, and called IPP.
They guy at IPP said that 1/8" would hold way more than 40psi. The camera cost me $32 but it is better quality that i expected, and talkes 640x480 pics.I'm off to open the camera and solder wires to the shutter btn. On monday ill go back to lumberworld to get them to cut the pipe to size. I need to figure out how to attach the lexan to one of the caps.
"If the women don't find you hansome, they should at least find you handy" -Red Green |
|
|
|
Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Nov 14 2005 : 09:00:13 AM
|
The removable pipe cap is generally called a "cleanout". They usually have a raised square section to be gripped by a wrench. I would grind that off, then grind out the circle leaving about 1/2" as a flange to attach the Lexan. Thick Lexan is easy to get. Just cut it to size, drill a bunch of holes around the outside edge, and bolt it on. Use sealant in all the bolt holes and between the Lexan and the ABS. Since the Lexan is bolted to the OUTSIDE of the cleanout, the pressure of the water will push it inwards and improve the seal.
|
|
|
|
yo_tyler
Apprentice
Canada
87 Posts |
Posted - Nov 14 2005 : 12:50:15 PM
|
What i got where test caps. there like an end cap, but not ment to be permenent. It wasn't worth the $7 for the end cap, and $20 for the cleanout. Im going to cement one cap on, and the other will have the window, and just gets pushed on the and caulked to keep any water out. the calc cam be peeled off when i need to open it. The window will get a gasket, and an epoxy seal, then will be bolted to the cap. Other features will be a piece of 3/4" pvc for a sight, and a handle on the bottom for holding, and to clip a short teather too. I'll be working on it lots today, becouse i want to test it on wendsday, so i'll post pictures tonight.
"If the women don't find you hansome, they should at least find you handy" -Red Green |
|
|
|
cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Nov 14 2005 : 6:34:02 PM
|
$20 for a cleanout!? Even in Canadian currency that seems a bit much.
I bet if you looked around a bit, you could find one for half the price.
http://daxter12.topcities.com <Updated:July |
|
|
|
yo_tyler
Apprentice
Canada
87 Posts |
Posted - Nov 14 2005 : 8:21:24 PM
|
Yup, thats why i didn't get it. $18.99 for the cap and the part the cap threds into. the regualar end caps were $8.99. So i bought the temp caps for 4.99 ea.
"If the women don't find you hansome, they should at least find you handy" -Red Green |
|
|
|
Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Nov 15 2005 : 11:16:30 AM
|
If you are talking about the thin orange or blue plastic test caps, they won't work. They are not actually made of ABS, adn thus will not glue to the pipe. They are also very thin and too flexable to bolt on the Lexan window.
I don't know where you are shopping, but $20 for a cleanout is about $12 too much. Instead of buying at a hardware store, go to a real plumbing store that deals with contractors.
I'm not sure how you are going to use epoxy in place of a gasket. Epoxy dries hard, while a gasket must remain soft. Hard epoxy will crack if anything flexes and cause a leak. You need to use caulking/gasket, bolts, and maybe o-rings to seal the heads of the bolts. Look at how a diving bell is constructed.
|
|
|
|
yo_tyler
Apprentice
Canada
87 Posts |
Posted - Nov 15 2005 : 11:49:06 AM
|
OK, I'm returning the temp caps, and I'm going to call all the plumbing stores to see what the real things will cost. The window will have a gasket between the lexan and abs, and the gasket gets put on the inside of the bolts. once bolted ill use some flexible plastic epoxy to seal all around the edge of the window. In order to control the shutter, i soldered two wires onto the switch, and will run them outside of the enclosure, onto a large button. What is the wire insulation made of? Would it be pvc? i need to figure out what kind of glue to use to seal the hole it will come out of.
"If the women don't find you hansome, they should at least find you handy" -Red Green |
|
|
|
Topic |
|
Pressure tank ideas
