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Cheetah223
September 6th, 2008, 05:49 PM
I'm building a housing for my video camera using the simple pipe-with-a-cap method, almost everyone I see making housings use PVC, and I understand that PVC is pressure rated so the argument of why PVC is used isn't an issue for me. The issue is that Home Depot only has ABS pipe large enough to fit my camera (4"...and that's cutting it close) I picked up two feet to start the job on but I can't find any information relating to pressure handled by ABS ANYWHERE online, short of buying the ASTM specs for $50 to download.

Does anyone know how much pressure 4" sch 40 cellular core ABS can hold? It'll need to hold up and be useable at 100' max. Should I toss it in a dumpster and travel farther until I get my hands on PVC?

350xfire
September 6th, 2008, 06:33 PM
I don' think you'll have a problaem. 100' is about 45 psi and that's not really much. Just make sure the clear window can handle it.

Lone Frogman
September 6th, 2008, 07:10 PM
Dump it.

4 "PVC 40 is 220 psi, 4" PVC 80 is 320 psi. ABS is used for non pressure.

Cheetah223
September 6th, 2008, 07:13 PM
I'm only curious because there's always an operating pressure and a bursting pressure..I figure 100fsw is closer to 60psi, though I may have the math wrong. Just to keep it safe I want an operating pressure over 100psi, and a bursting pressure higher than that. I don't want to cut it close with a $500 camera inside..As for the window, I may not even put one on. I'm using it with a bullet cam, so I'm just going to run a wire through a gland like a canister light to the external camera and just use the actual camcorder as a recording medium..

EDIT: Frogman, you posted as I was typing..Like I said, I know the pressures and differences between ABS and PVC, I don't really care that PVC is pressure rated and ABS isn't, as long as ABS is strong enough..I'm hoping someone has used ABS before. Plenty of can lights seem to have ABS canisters from pictures..

fdog
September 6th, 2008, 07:18 PM
If you're only going to 100', then just use a Pelican Micro-case, like the Pelican 1020 (http://www.all-pelican-cases-4-less.com/detail_pelican_1020.html).

The clear ones are good for peace of mind. They'll take the depth. Don't ask me how I know, I just know they will.


All the best, James

spectrum
September 6th, 2008, 07:49 PM
I can't imagine a 4 inch schedule ABS cylinder being bothered at 100 feet .

Pete

Cheetah223
September 6th, 2008, 09:06 PM
I thought about a Pelican case, but on top of not being sure if they'd take the pressure, I need to fit my camera as well as a battery and a ton of wires into the case, and the only pelican cases I can find that are big enough in all the dimensions to fit everything are WAY too big in at least one other dimension for what I want. I'm using the pipe to keep the size down, my camera fits perfectly, can't even rattle when it's slid into the 4" pipe.

Packhorse
September 6th, 2008, 10:16 PM
..I figure 100fsw is closer to 60psi, though I may have the math wrong...
You are correct and wrong :rofl3:

100ft is about 60 psi absolute but since you will not be forming a vacuum in your housing before you dive or sealing it in outerspace the pressure differential will be about 45psi. or 14.5 psi per 33ft

350xfire
September 6th, 2008, 11:16 PM
Or it takes 2.31 feet of water column per psi, thus, 100/2.31 = 43.2. About 45... Of course, that is for fresh water, so a salt water correction may be closer to 45 psi...

merxlin
September 7th, 2008, 12:25 AM
One note about the 4" ABS pipe: It is a foam core pipe with an ABS inner and outer shell. It is very strong, but I am not sure how drilling or attachments will stand up.

Cheetah223
September 7th, 2008, 04:59 AM
...since you will not be forming a vacuum in your housing before you dive or sealing it in outerspace...

Good call, guess I need to think a little deeper into things before I speak haha. :lotsalove:

As for drilling, I'm hoping to heat it up and stretch a ring around one end and drill clamps to that instead of into the pressure vessel, and the solid endcap I got seems to be solid ABS as opposed to having the cellular core like the pipe does..I should be able to tell that when I drill it for the gland, and I'll obviously do a couple of dry tests before I throw anything but wires inside the housing to be sure..

Only thing I worry about at this point, PVC won't burn, at least not as hot as I've been able to get it, it just melts and boils and extinguishes any flame as soon as the source is taken away...So throwing it in the oven to make it malleable doesn't concern me too much. ABS is an entirely new beast to me - if I toss it in a 400* oven for a few minutes, am I going to be burning down the house, or gassing myself when I open the oven to pull it out?

Lone Frogman
September 7th, 2008, 07:18 AM
Good call, guess I need to think a little deeper into things before I speak haha. :lotsalove:

As for drilling, I'm hoping to heat it up and stretch a ring around one end and drill clamps to that instead of into the pressure vessel, and the solid endcap I got seems to be solid ABS as opposed to having the cellular core like the pipe does..I should be able to tell that when I drill it for the gland, and I'll obviously do a couple of dry tests before I throw anything but wires inside the housing to be sure..

Only thing I worry about at this point, PVC won't burn, at least not as hot as I've been able to get it, it just melts and boils and extinguishes any flame as soon as the source is taken away...So throwing it in the oven to make it malleable doesn't concern me too much. ABS is an entirely new beast to me - if I toss it in a 400* oven for a few minutes, am I going to be burning down the house, or gassing myself when I open the oven to pull it out?

He's a link on PVC SAFETY OF PVC IN ACCIDENTAL FIRE (http://www.vec.gr.jp/english/library/fire/1.html)

Cheetah223
September 7th, 2008, 04:19 PM
I appreciate the effort and the information, but again - maybe I didn't make it clear in my original post - I'm working with ABS, *not* PVC, and therefore am not interested in what the capabilities of PVC are. I had to drive 50 miles to get my hands on ABS big enough to fit my camera, and PVC is going to be somewhere beyond that - so PVC isn't an option...I'm looking for relevant information to the materials I've got to work with.. :hm:

Lone Frogman
September 8th, 2008, 06:11 AM
I never tried to heat ABS in a oven. But I have seen ABS get really flexible just laying in the hot summer sun.

cwkline
September 8th, 2008, 11:44 AM
I would try to get some ABS Sch 40 pipe, and not rely on the foam core. You might want to try an RV shop, as I believe that is what they still use.
You also need to remember that ABS breaks down quickly and can become brittle with exposure to sunlight. It also can become very brittle when exposed to cold temps.
You may want to consider PVC Sch 80.
Just a plumbers point of view.

micklock
September 8th, 2008, 11:57 AM
Does anyone know how much pressure 4" sch 40 cellular core ABS can hold? It'll need to hold up and be useable at 100' max. Should I toss it in a dumpster and travel farther until I get my hands on PVC?

Check with a local golf course, we have up to 6" schedule 80 pvc. They might have some scraps laying around.

treasurehunter
September 8th, 2008, 04:42 PM
I'm a plumbing contractor and only use abs for drain pipes. I know pvc is really out of the way for you but you should consider not only the pipe but the glue used for abs not sure it will hold up to that kind of presure,it might but with an expensive gadjet inside i'd be careful. Second there are two kind of pvc Pressure and drainage. And each kind has the proper glue for its purpose. The problem with the pvc of that size is cost and you will have to buy at least 12 feet also the pipe can be brittle if knock hard.

Cheetah223
September 8th, 2008, 07:11 PM
Thanks for the ideas on getting my hands on PVC, and the information on ABS. PVC is no stranger to me, my dad owns a plumbing company, so I've got about eight years experience dealing with PVC, but we never used ABS, hence all the questions dealing with ABS. I'll get in touch with my dad and see if he can get me a couple feet of 4" sch 80 and come up with a reasonable way to mail it from Montana to SoCal, it seems like a gamble if I go through with the ABS..

couv
September 8th, 2008, 08:33 PM
You are correct and wrong :rofl3:

100ft is about 60 psi absolute but since you will not be forming a vacuum in your housing before you dive or sealing it in outerspace the pressure differential will be about 45psi. or 14.5 psi per 33ft

Right,

Each foot of sea water exerts .445 psi
Each foot of fresh water exerts .432 psi

When estimating, just use 1/2 lb per foot.

Here is some more just about useless information.


Sea water weighs 64 lbs per cubic foot
Fresh water weighs 62.4 lbs per cubic foot

c

pdh
September 13th, 2008, 05:23 AM
I appreciate the effort and the information, but again - maybe I didn't make it clear in my original post - I'm working with ABS, *not* PVC, and therefore am not interested in what the capabilities of PVC are. I had to drive 50 miles to get my hands on ABS big enough to fit my camera, and PVC is going to be somewhere beyond that - so PVC isn't an option...I'm looking for relevant information to the materials I've got to work with.. :hm:

Cheetah, I made a housing from ABS. The reason was I found it much easier to glue than PVC as it melts using that Acetone based glue. I don't think the burst pressures quoted before in this thread are going to be an issue. Pressure is different when trying to crush things as opposed to trying to explode them and my ABS housing went to 42 metres with no problems and I'm sure would have gone a lot deeper. I currently make housings from Perspex (acrylic) and is not pressure rated at all and which would probably explode with fairly low pressures in them but managed to get to 146 metres before breaking (and that was the end plate, not the tube). See my page below - the Mark I and Mark II are all ABS. The Mark III is all acrylic.

Paul's Homemade Underwater Video Housing (http://www2.mrc-lmb.cam.ac.uk/personal/pdh/housing/index.html)

At 42 metres on the James Barrie in Scapa Flow - no lights (http://www2.mrc-lmb.cam.ac.uk/personal/pdh/scapa/Movies/James%20Barrie.mov)

My advice is try it. It will probably work well, within sensible depth limits.

regards Paul.

dave4868
September 13th, 2008, 07:28 AM
I'm only curious because there's always an operating pressure and a bursting pressure..I figure 100fsw is closer to 60psi, though I may have the math wrong. Just to keep it safe I want an operating pressure over 100psi, and a bursting pressure higher than that. I don't want to cut it close with a $500 camera inside..As for the window, I may not even put one on. I'm using it with a bullet cam, so I'm just going to run a wire through a gland like a canister light to the external camera and just use the actual camcorder as a recording medium

Since you already have the 4" ABS and might not be able to get PVC cheap, I'd suggest you go ahead and build the housing and pressure-test it empty until you're satisfied it won't fail. I'd test it to about twice the expected working pressure for piece of mind. A big pressure pot might not be around, but maybe you've got some deep water nearby.... :D

I agree with (pdh) Paul's statement that crush pressure strength will be different than burst pressure strength.

(By the way, very nice page of homemade housings, Paul!)

Out of curiosity, Cheetah223, why aren't you using the optics of the video camera itself? Not working or not sensitive enough in low light?

Dave C

Cheetah223
September 13th, 2008, 01:50 PM
The main reason I'm using the helmet camera instead of the video camera itself is because I have it. I bought the helmet camera before I went to Iraq so I could have video on patrol and during raids and such and not have to worry about fumbling with a camera at all. It worked well in that environment, and it's (supposedly) waterproof to 100ft. I'll be among the first to admit that I've still got plenty to deal with just diving, so at least for now I don't want to add handling a camera to the equation..

dave4868
September 13th, 2008, 05:29 PM
The main reason I'm using the helmet camera instead of the video camera itself is because I have it. I bought the helmet camera before I went to Iraq so I could have video on patrol and during raids and such and not have to worry about fumbling with a camera at all. It worked well in that environment, and it's (supposedly) waterproof to 100ft. I'll be among the first to admit that I've still got plenty to deal with just diving, so at least for now I don't want to add handling a camera to the equation..

First, I feel indebted to you for your service! You have my deepest respect and appreciation!

Regarding waterproof ratings, they're often "static" ratings which may be significantly better than the actual failure potential under dynamic conditions.

If you want to "bullet proof" your bullet camera, you might make a separate housing for it out of 2" PVC like the one I made for my towed/drop camera (see image below).

Dave C

http://www.scubaboard.com/gallery/data/500/medium/Towed_UW_video_camera_and_housing_R900.jpg

helimvee
September 13th, 2008, 08:58 PM
Paul, very nice work on the website and the housings. When do you find time to dive?

What kind of RC are you in to? I was flying a heli, until I discovered flying (scuba) underwater.

-Andrew

pdh
September 14th, 2008, 12:15 PM
Paul, very nice work on the website and the housings. When do you find time to dive?

What kind of RC are you in to? I was flying a heli, until I discovered flying (scuba) underwater.

-Andrew

Planes and Helis when I get the time. I'm also building the scratch 1/8 Tiger tank which will be fully RC - follow the links.

I don't watch much TV and I have a heater in my shed - that leaves cold nights to make stuff and go diving at the weekends :D Current project is also a very fast DPV - Think X-scooter or Gavin. 10" diameter thick wall PVC pipe (only because it was free - ABS would do :D) - 24 volts - 750 watts - electronic speed control. It should get to 100 metres if I'm lucky. Cost is around $600 so 1/10 the price of buying one. I'll post some pics once it's done.

P.

Old Skool Diver
September 14th, 2008, 09:33 PM
I would not reccomend ABS. In the early 70"s, I worked at Bamboo Reef in San Francisco. Al Gidding built housings there from aluminum and PVC. The ABS is too brittle. Order 2 feet of PVC online or go to a plumbing store. We also used to cut dome ports from the dome of a ships compass ( they weren't electronic then). If you can find one, just cut it on a band saw. Far better than a flat port.

pranam
September 30th, 2008, 10:37 PM
HI
i'm just novice in underwater video filming, so i build my own 4" video housing using PVC 40, even added my dive lilghts it works great till now, So i been thinking HOW could add some MECHANICAL controls in it, ikelite parts had been extremely difficult to get.
Thanks for help

gert7to3
October 5th, 2008, 09:05 PM
Here's an ABS plumbing spec sheet:

www.nibco.com/assets/ABSGUIDE.pdf

A google seach on ABS plastic fire properties turned up a yahoo post that said:

"The aging characteristics of the polymers are largely influenced by the polybutadiene content, and it is normal to include antioxidants in the composition. On the other hand, while the cost of producing ABS is roughly twice the cost of producing polystyrene, ABS is considered superior for its hardness, gloss, toughness, and electrical insulation properties. However, it will be degraded (dissolve) when exposed to acetone. ABS is flammable when it is exposed to high temperatures, such as a wood fire. It will "boil", then burst spectacularly into intense, hot flames.

So if you keep your oven below the ignition point of wood, you'll be ok.

Instead of trying to heat shrink a boss made of ABS around your housing body, why not just cut off the end of a PVC end cap and use the remaining band?

Cheetah223
October 6th, 2008, 12:54 AM
Awesome, thanks for the heads up gert, it covered the idea of heating it for sure, the link says it self ignites over 800*, so I'd definitely be in the clear to take it up to a couple hundred to mold it, but you also make a very good point about just hacking up an end cap and using it instead of stretching the pipe on my own. This is why I love having access to other people's minds :D

couv
October 15th, 2008, 09:08 PM
Just an interesting tid bit. I just looked at one of my store bought dive lights (Underwater Kinetics) and the info placard reads, "Lexan/ABS Construction."

rivrdiving
October 15th, 2008, 09:40 PM
I figure you could make a test housing and take it on a dive and see what happens,
Sounds like a good reason to make a dive to me..LOL
Ron

jbcpok
October 20th, 2008, 07:28 PM
What would the test housing look like? Do you think it could be water proof?


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